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The accurate prediction of protein-ligand binding affinity belongs to one of the central goals in computer-based drug design. Molecular dynamics (MD)-based free energy calculations have become increasingly popular in this respect due to their accuracy and solid theoretical basis. Here, we present a combined study which encompasses experimental and computational studies on two series of factor Xa ligands, which enclose a broad chemical space including large modifications of the central scaffold. Using this integrated approach, we identified several new ligands with different heterocyclic scaffolds different from the previously identified indole-2-carboxamides that show superior or similar affinity. Furthermore, the so far underexplored terminal alkyne moiety proved to be a suitable non-classical bioisosteric replacement for the higher halogen-π aryl interactions. With this challenging example, we demonstrated the ability of the MD-based non-equilibrium free energy calculation approach for guiding crucial modifications in the lead optimization process, such as scaffold replacement and single-site modifications at molecular interaction hot spots.

Purpose Preeclampsia occurs in up to 15% of pregnancies and constitutes a major risk factor for cardiovascular disease. This observational cohort study aimed to examine the association between preeclamptic pregnancies and cardiovascular outcomes as well as primary and specialized care utilization after delivery. Methods Using statutory claims data we identified women with singleton live births between 2010 and 2017. Main outcomes included the occurrence of either hypertension or cardiovascular disease after one or more preeclamptic pregnancies, number of contacts to a general practitioner or cardiologist after delivery and prescribed antihypertensive medication. Data were analyzed using Cox proportional hazard regression models adjusted for maternal age, diabetes, dyslipidemia, and obesity. Results The study cohort consisted of 181,574 women with 240,698 births. Women who experienced preeclampsia once had an increased risk for cardiovascular (hazard ratio, HR = 1.29) or hypertensive (HR = 4.13) events. In women affected by recurrent preeclampsia, risks were even higher to develop cardiovascular disease (HR = 1.53) or hypertension (HR = 6.01). In the following years after delivery, general practitioners were seen frequently, whereas cardiologists were consulted rarely (0.3 and 2.4%). Conclusion Women affected by preeclampsia experience an increased risk of developing chronic hypertension and cardiovascular disease, especially those with recurrent preeclampsia. Future medical guidelines should take this potential risk into account.

The selective activation of sp3 carbon–hydrogen bonds in the presence of multiple C–H bonds is challenging and remains of supreme importance in chemical research. Late-stage modification of complex molecules via sp3 C–H activation is of high prevalence in organic synthesis. Herein, we describe the activation of a C(sp3)–H bond in the α-position to an amine via a carbanion intermediate. In the presence of several α-amine sites, only one specific position is selectively activated. Applying this protocol, the proposed carbanion intermediate was effectively trapped with different electrophiles such as deuterium (D+), tritium (T+), or carbonyl compounds compiling over 50 examples. Further, this methodology was used to install deuterium or tritium in different drug-derivatives (>10 drugs) at a selected position in a late-stage functionalization. In addition, the protocol is suitable for a gram-scale synthesis, and a detailed mechanistic investigation has been carried out to support our hypothesis.

The spread of antimicrobial resistance (AMR) is becoming a more and more important global threat to human health. With regard to current medical needs, penetration into the site of infection represents the major challenge in the treatment of infections caused by Gram-positive bacteria.

Seven new polyketides, termed veramycins, were isolated from a Streptomyces sp. from the Sanofi microbial strain collection along with their known congeners NFAT-133 and TM-123. Veramycin A, an α-pyrone congener of TM-123 and NFAT-133 showed an increased baseline deoxy-glucose uptake in the absence of insulin in a modified L6 rat skeletal muscle cell line (L6 GLUT4 AS160-like cells). In addition, both compounds slightly increased the sensitivity to insulin in this cell line. Total syntheses of NFAT-133, TM-123 and veramycin A were accomplished starting from a central building block, which bears the three contiguous stereogenic centers of this polyketide family. Our approach enables an efficient, selective and flexible access to all possible isomers of the stereotriad for further exploration of this series as a potential anti-diabetic lead structure as exemplified by the synthesis of an NFAT-133 epimer. Finally, the corresponding biosynthetic gene cluster (BGC) was identified by genome sequencing and gene inactivation. Based on feeding experiments, a biosynthetic pathway was proposed, which enabled access to new veramycin A analogs by precursor-directed biosynthesis.

The recently discovered natural product (NP) (+)-floyocidin B with antimicrobial activity against Mycobacterium tuberculosis displays a hitherto unknown dihydroisoquinolinone scaffold in the class of the epoxyquinone NPs. The 4,5-regioselective functionalization of 2-chloropyridines was identified as a suitable strategy leading to the total syntheses of (+)-floyocidin B and analogs. In this paper, we present the long and winding evolution process to the final synthetic pathway, including model systems for route scouting and elucidation of side products, which enabled us to understand the unique reactivity of this unprecedented scaffold. A special focus was laid on method studies with different 2-chloropyridines, disclosing an unexpected effect of the 2-chloro substituent on the regioselectivity compared to 2-unsubstituted or carbon-substituted pyridines. Finally, a head-to-head comparison with the previously described synthesis of all four stereoisomers of the NP (−)-avicennone C revealed significant differences in the reactivity of these structurally closely related scaffolds.

Zusammenfassung Einleitung Multigen-Assays werden zunehmend als Entscheidungshilfe für eine Chemotherapie beim Mammakarzinom verwendet. Wir stellen hier den 21-Gen-Recurrence-Score (RS) von Patientinnen mit Brustkrebs vor, die routinemäßig in Deutschland untersucht wurden. Patientinnen und Methoden 4695 Patientinnen mit hormonrezeptorpositivem und HER2-negativem Brustkrebs im Frühstadium (pT1–3, pN0–1, M0) wurden einer retrospektiven Analyse unterzogen. Bei diesen Patientinnen wurde in Deutschland zwischen November 2015 und Juli 2018 der Genexpressionstest Oncotype DX zur Ermittlung des Recurrence-Scores durchgeführt. Die Klassifikation der RS-Gruppen erfolgte gemäß der TAILORx Studie (RS: 0–10; 11–25; 26–100). Ergebnisse Von diesen Patientinnen wurden 21 % in die niedrige RS-Gruppe, 63 % in die mittlere RS-Gruppe, und 15 % in die hohe RS-Gruppe eingeteilt. 1772 (81 %) von 2175 Patientinnen im Alter von über 50 Jahren und ohne Lymphknotenbefall wurden entweder in die niedrige oder die mittlere RS-Gruppe eingeteilt. Der Prozentsatz an Patientinnen mit einem niedrigen oder mittleren RS betrug 90 % bei Patientinnen ohne Lymphknotenbefall (1284 von 1432 Patientinnen), 79 % bei Patientinnen mit einem hohen (≥ 20 %) Ki-67-Wert (1829 von 2310 Patientinnen), 86 % bzw. 70 % bei Patientinnen mit G2- bzw. G3-Tumoren (3244 von 3762 Patientinnen bzw. 368 von 522 Patientinnen), 88 % bei Patientinnen mit einem Tumordurchmesser von > 5 cm (140 von 159 Patientinnen) und 82 % bei Patientinnen ohne Lymphknotenbefall, aber mit einem hohen klinischen Risiko (1110 von 1352). Schlussfolgerung Die Verteilung des 21-Gens RS bei deutschen Patientinnen, die in der klinischen Routinepraxis getestet wurden, deutet darauf hin, dass gemäß den Ergebnissen der TAILORx-Studie die Chemotherapie bei den meisten dieser Patientinnen keinen Nutzen hat.

Preeclampsia is associated with a substantially increased long-term risk for cardiovascular, cerebrovascular and renal disease. It remains unclear whether and to which extent specialized medical postpartum care is sought. We aimed to assess current utilization of postpartum primary and specialized care and medication prescription behavior in women who experienced preeclampsia. This retrospective observational study based on statutory claims data included 193,205 women with 258,344 singleton live births between 2010 and 2017 in Southern Germany. Postpartum care was evaluated by analyzing and comparing the frequency of medical consultations in primary and specialized care and prescriptions for antihypertensive medication among women with and without preeclampsia up to 7.5 years after delivery. Gynecologists and general practitioners were the main health care providers for all women. Although specialized postpartum care was sought by more women after preeclampsia, the effect size indices revealed no considerable association between a history of preeclampsia and the utilization of specialized outpatient aftercare (e.g. 2% vs. 0.6% of patients with and without preeclampsia who consulted a nephrologist during the first year postpartum, r = 0.042). Preeclampsia was associated with an increased risk to take any antihypertensive medication after delivery (HR 2.7 [2.6; 2.8]). Postpartum referral to specialized outpatient care and quarterly prescriptions of antihypertensives following preeclampsia failed to match the early and rapidly increased incidence and risk of hypertension. These data highlight the missed opportunity to implement a reasonable follow-up strategy and prevention management in order to achieve long-term clinical benefits.

Herein, we describe the myxobacterial natural product Corramycin isolated from Corallococcus coralloides. The linear peptide structure contains an unprecedented (2R,3S)-γ-N-methyl-β-hydroxy-histidine moiety. Corramycin exhibits anti-Gram-negative activity against Escherichia coli (E. coli) and is taken up via two transporter systems, SbmA and YejABEF. Furthermore, the Corramycin biosynthetic gene cluster (BGC) was identified and a biosynthesis model was proposed involving a 12-modular non-ribosomal peptide synthetase/polyketide synthase. Bioinformatic analysis of the BGC combined with the development of a total synthesis route allowed for the elucidation of the molecule's absolute configuration. Importantly, intravenous administration of 20 mg kg

Herein, we describe the myxobacterial natural product Corramycin (1) isolated from Corallococcus coralloides (C. coralloides). Corramycin is a linear peptide containing an unprecedented (2R,3S)  N-methyl-β-hydroxy histidine moiety and exhibiting anti-Gram-negative activity against Escherichia coli. Moreover, we describe the Corramycin biosynthetic gene cluster (BGC) and propose a biosynthesis model involving a 12-modular non-ribosomal peptide synthetase (NRPS)/polyketide synthase (PKS). Bioinformatic analysis of the BGC combined with the development of a total synthesis route allowed for the elucidation of the molecule’s absolute configuration. Furthermore, we show that the uptake of Corramycin in E. coli depends on two transporter systems, SbmA and YejABEF. Importantly, intravenous administration of 30 mg kg 1 of Corramycin in an E. coli mouse infection model resulted in significantly reduced colony forming units (CFU) and in 60 % survival of animals, with no toxic effects observed in vitro or in vivo. Corramycin is thus an intriguing innovative starting point to develop a potent antibacterial drug against hospital acquired infections.

With progress in genome sequencing and data sharing, 1,000s of bacterial genomes are publicly available. Genome mining-using bioinformatics tools in terms of biosynthetic gene cluster (BGC) identification, analysis, and rating-has become a key technology to explore the capabilities for natural product (NP) biosynthesis. Comprehensively, analyzing the genetic potential of the phylum Bacteroidetes revealed Chitinophaga as the most talented genus in terms of BGC abundance and diversity. Guided by the computational predictions, we conducted a metabolomics and bioactivity driven NP discovery program on 25 Chitinophaga strains. High numbers of strain-specific metabolite buckets confirmed the upfront predicted biosynthetic potential and revealed a tremendous uncharted chemical space. Mining this data set, we isolated the new iron chelating nonribosomally synthesized cyclic tetradeca- and pentadecalipodepsipeptide antibiotics chitinopeptins with activity against Candida, produced by C. eiseniae DSM 22224 and C. flava KCTC 62435, respectively.

Increasingly sensitive analytical instruments and robust downstream data processing tools have revolutionized natural product research over the past decade. A molecular networking-guided survey led...

Background Multigene assays are being used increasingly to aid in decision-making about chemotherapy in breast cancer. Here, we present the 21-gene recurrence score (RS) of patients tested in routine clinical practice in Germany. Patients and Methods In a retrospective analysis, 4695 patients with hormone receptor-positive and HER2-negative early breast cancer (pT1 – 3, pN0 – 1, M0) were included in whom RS testing was conducted in Germany between November 2015 and July 2018. RS groups as defined in the TAILORx trial (RS result 0 – 10; 11 – 25; 26 – 100) were used. Results Of these patients, 21% were assigned to the low RS group, 63% to the midrange RS group, and 15% to the high RS group. 1772 (81%) of 2175 node-negative patients over 50 years of age were grouped either into the low RS group or the midrange RS group. The portion of patients with a low or midrange RS was 90% among node-positive patients (1284 of 1432 patients), 79% among patients with Ki-67-high (≥ 20%) tumors (1829 of 2310 patients), 86% vs. 70% among patients with G2 and G3 tumors (3244 of 3762 patients and 368 of 522 patients), respectively, 88% among patients with a tumor size of > 5 cm (140 of 159 patients), and 82% among node-negative patients at high clinical risk (1110 of 1352). Conclusions The distribution of the 21-gene RS in German patients that were tested in routine clinical practice indicates that, according to the results of the TAILORx trial, chemotherapy may not be beneficial in most of these.

Protease inhibitors represent a promising therapeutic option for the treatment of parasitic diseases such as malaria and human African trypanosomiasis. Falcitidin was the first member of a new class of inhibitors of falcipain-2, a cysteine protease of the malaria parasite Plasmodium falciparum. Using a metabolomics dataset of 25 Chitinophaga strains for molecular networking enabled identification of over 30 natural analogues of falcitidin. Based on MS/MS spectra, they vary in their amino acid chain length, sequence, acyl residue, and C-terminal functionalization; therefore, they were grouped into the four falcitidin peptide families A-D. The isolation, characterization, and absolute structure elucidation of two falcitidin-related pentapeptide aldehyde analogues by extensive MS/MS spectrometry and NMR spectroscopy in combination with advanced Marfey’s analysis was in agreement with the in silico analysis of the corresponding biosynthetic gene cluster. Total synthesis of chosen pentapeptide analogues followed by in vitro testing against a panel of proteases revealed selective parasitic cysteine protease inhibition and, additionally, low-micromolar inhibition of α-chymotrypsin. The pentapeptides investigated here showed superior inhibitory activity compared to falcitidin.

The isotopic labelling of small molecules is integral to drug development and for understanding biochemical processes. The preparation of carbon-labelled α-amino acids remains difficult and time consuming, with established methods involving label incorporation at an early stage of synthesis. This explains the high cost and scarcity of C-labelled products and presents a major challenge in

a-Amino acids are among the essential chemical building blocks of life. These structures are embedded in many small molecule pharmaceuticals and are the primary components of peptide-based therapeutics and biologics. Isotopically labeled a-amino acids and their derivatives have widespread use in structural and mechanistic biochemistry, quantitative proteomics, absorption distribution metabolism and excretion (ADME) profiling, and as imaging agents in positron emission tomography (PET) techniques. The preparation of carbon-labeled a-amino acids remains difficult and time consuming, with established methods involving label incorporation at an early stage of synthesis. This explains the high cost and scarcity of C-labeled products and presents a major challenge in 11C applications (11C t1/2 = 20 min). Here we report that simple aldehydes catalyze the isotopic carboxylate exchange of native a-amino acids with *CO2 (* = 14, 13, 11). Proteinogenic a-amino acids and many non-natural variants containing diverse functional groups undergo labeling. The reaction likely proceeds via the trapping of *CO2 by imine-carboxylate intermediates to generate aminomalonates that are prone to monodecarboxylation. Tempering catalyst electrophilicity was key to preventing irreversible aldehyde consumption. The pre-generation of the imine carboxylate intermediate allows for the rapid and late-stage 11C-radiolabeling of a-amino acids in the presence of 11CO2.

Tuberculosis represents one of the ten most common courses of death worldwide and the emergence of multidrug-resistant M. tuberculosis makes the discovery of novel anti-tuberculosis active structures an urgent priority. Here, we show that (+)-floyocidin B representing the first example of a novel dihydroisoquinoline class of fungus-derived natural products, displays promising antitubercular hit properties. (+)-Floyocidin B was identified by activity-guided extract screening and its structure was unambiguously determined by total synthesis. The absolute configuration was deduced from a key synthesis intermediate by single crystal X-ray diffraction analysis. A hit series was generated by the isolation of further natural congeners and the synthesis of analogs of (+)-floyocidin B. Extensive biological and physicochemical profiling of this series revealed first structure-activity relationships and set the basis for further optimization and development of this novel antitubercular scaffold.

Protease inhibitors represent a promising therapeutic option for the treatment of parasitic diseases such as malaria and human African trypanosomiasis. Falcitidin was the first member of a new class of inhibitors of falcipain-2, a cysteine protease of the malaria parasite Plasmodium falciparum. Using a metabolomics dataset of 25 Chitinophaga strains for molecular networking enabled identification of over 30 natural analogs of falcitidin. Based on MS/MS spectra, they vary in their amino acid chain length, sequence, acyl residue, and C-terminal functionalization; therefore, they were grouped into the four falcitidin peptide families A-D. The isolation, characterization and absolute structure elucidation of two falcitidin-related pentapeptide aldehyde analogs by extensive MS/MS spectrometry and NMR spectroscopy in combination with advanced Marfey’s analysis was in agreement with the in silico analysis of the corresponding biosynthetic gene cluster. Total synthesis of chosen pentapeptide analogs followed by in vitro testing against a panel of proteases revealed selective parasitic cysteine protease inhibition and additionally low-micromolar inhibition of α-chymotrypsin. The pentapeptides investigated here showed superior inhibitory activity compared to falcitidin.

The selective activation of sp3 carbon-hydrogen bonds in presence of multiple C¬-H bonds is challenging and remains of supreme importance in chemical research. Herein, we describe the activation of a C(sp3) H bond in α position to an amine via a carbanion intermediate. In the presence of several α amine sites, only one specific position is selectively activated. Applying this protocol, the proposed carbanion intermediate was effectively trapped with different electrophiles such as deuterium (D+), tritium (T+), or carbonyl compounds compiling over 50 examples. Further, this methodology was used to install deuterium or tritium in different drug derivatives (> 10 drugs) at a selected position in a late-stage functionalization. In addition, the protocol is suitable for a gram-scale synthesis and a detailed mechanistic investigation has been carried out to support our hypothesis.

Comprehensive genomic profiling and biomarker-based therapeutic strategies are currently used in clinical trials and in innovative health care systems including the center for personalized medicine network. Systematic assessments of patient-reported outcomes are warranted to gain insight into the perspective of patients and their relatives during biomarker-based therapies. In the present study, we focused on health-related quality of life (HRQoL), psychosocial situation, and physical symptoms in patients treated at the Center for Personalized Medicine Tübingen. First, we retrospectively evaluated symptom burden of n=265 (neuro-)oncological patients in the Molecular Tumor Board (MTB). Sixty percent of patients reported at least 1 neurological symptom, and psychosocial burden/unmet needs were high (overall 156/265; 59%, patients with malignant tumors n=86/106; 81%, Fisher’s exact, p < 0.0001). We therefore developed an app by 14 expert rounds and pretesting including validated assessments of HRoL, symptom und psychological burden and tested it in a pilot study. We conducted a structured interview with users 3 months afterwards to assess the app’s usability and feasibility. The interview was transcribed and analyzed according to a qualitative content analysis. So far, a total of 10 patients and caregivers have been enrolled in this pilot study. They reported that (i) the app is compatible with their daily routine (median 9.3, range 0-10), that (ii) they are more aware of their health status, which was rated as positive, and that (iii) completing app-based questionnaires was easier compared to paper questionnaires. Two patients reported technical problems, which were resolved timely. The pilot study proved feasibility and acceptance of the app. The app might optimize symptom burden assessment, adapted to the patients’ profiles. The next step is to prospectively compare HRQoL before and after start of targeted therapy in a multicenter study.

Emerging antimicrobial resistance urges the discovery of antibiotics with unexplored, resistance-breaking mechanisms. Armeniaspirols represent a novel class of antibiotics with a unique spiro[4.4]non-8-ene scaffold and potent activities against Gram-positive pathogens. We report a concise total synthesis of (±) armeniaspirol A in six steps with a yield of 20.3% that includes the formation of the spirocycle through a copper-catalyzed radical cross-coupling reaction. In mechanistic biological experiments, armeniaspirol A exerted potent membrane depolarization, accounting for the pH-dependent antibiotic activity. Armeniaspirol A also disrupted the membrane potential and decreased oxygen consumption in mitochondria. In planar lipid bilayers and in unilamellar vesicles, armeniaspirol A transported protons across membranes in a protein-independent manner, demonstrating that armeniaspirol A acted as a protonophore. We provide evidence that this mechanism might account for the antibiotic activity of multiple chloropyrrole-containing natural products isolated from various origins that share a 4-acylphenol moiety coupled to chloropyrrole as a joint pharmacophore. We additionally describe an efflux-mediated mechanism of resistance against armeniaspirols., The antibiotic armeniaspirol A depolarized bacterial and mammalian cell membranes through a protonophore activity, that accounts for its potent antibiotic effects. A total synthesis of (±) armeniaspirol A was achieved in six steps.

With progress in genome sequencing and data sharing, 1000s of bacterial genomes are publicly available. Genome mining – using bioinformatics tools in terms of biosynthetic gene cluster (BGC) identification, analysis and rating – has become a key technology to explore the capabilities for natural product (NP) biosynthesis. Comprehensively, analyzing the genetic potential of the phylum Bacteroidetes revealed Chitinophaga as the most talented genus in terms of BGC abundance and diversity. Guided by the computational predictions, we conducted a metabolomics and bioactivity driven NP discovery program on 25 Chitinophaga strains. High numbers of peerless strain-specific metabolite buckets confirmed the upfront predicted biosynthetic potential and revealed a tremendous uncharted chemical space. Sourcing this dataset, we isolated the new iron chelating nonribosomally-synthesized cyclic tetradeca- and pentadecalipodepsipeptide antibiotics chitinopeptins with activity against Candida, produced by C. eiseniae DSM 22224 and C. flava KCTC 62435, respectively.TeaserCombination of omics-technologies revealed taxonomical hotspots for specialized metabolites within Bacteroidetes.

Background Mental disorders are common during the peripartum period and may have far-reaching consequences for both mother and child. Unfortunately, most antenatal care systems do not provide any structured screening for maternal mental health. As a consequence, mental illnesses are often overlooked and not treated adequately. If correctly diagnosed, cognitive behavioral therapy is currently the treatment of choice for mental illnesses. In addition, mindfulness-based interventions (MBIs) seem to represent a promising treatment option for anxiety and depression during the peripartum period. Considering the internet’s increasing omnipresence, MBIs can also be offered electronically via a (tablet) computer or smartphone (electronically based MBI = eMBI). Objective The current study aims to examine the clinical effectiveness and cost-effectiveness of an eMBI (the mindmom application) developed by an interdisciplinary team of gynecologists, psychologists, and midwives, teaching pregnant women how to deal with stress, pregnancy-related anxiety, and depressive symptoms. The study sample consists of pregnant women in their third trimester who screened positive for emotional distress. The mindmom study is a bicentric prospective randomized controlled trial (RCT), which is currently conducted at the University women’s hospitals of Heidelberg and Tübingen, Germany. Methods Within the scope of the routine prenatal care, pregnant women attending routine pregnancy care in Baden-Wuerttemberg, Germany, are invited to participate in a screening for mental distress based on the Edinburgh Postnatal Depression Scale (EPDS). Women with an EPDS screening result > 9 will be referred to one of the mindmom coordinating study centers and are offered counseling either face-to-face or via videotelephony. After an initial psychological counseling, women are invited to participate in an eMBI in their last pregnancy trimester. The study will enroll N = 280 study participants (N = 140 per group), who are randomized 1:1 into the intervention (IG) or control group (treatment as usual = TAU). All participants are requested to complete a total of 7 digital assessments (5 visits pre- and 2 follow-up visits postpartum), involving self-report questionnaires, sociodemographic and medical data, physiological measures, and morning cortisol profiles. The primary outcome will be depressive and anxiety symptoms, measured by the Edinburgh Postnatal Depression Scale, the State Trait Anxiety Questionnaire, and the Pregnancy-Related Anxiety Questionnaire. Secondary outcomes include mindfulness, satisfaction with birth, quality of life, fetal attachment, bonding, mode of delivery, and cost-effectiveness. Discussion This is the first German RCT to examine the (cost-)effectiveness of an eMBI on maternal mental health during pregnancy. If successful, the mindmom app represents a low-threshold and cost-effective help for psychologically distressed women during pregnancy, thereby reducing the negative impact on perinatal health outcome. Trial registration Deutsches Register Klinischer Studien, German Clinical Trials Register DRKS00017210. Registered on 13 January 2020. Retrospectively registered.

All four possible stereoisomers of the natural product (-)-avicennone C were synthesized using two different methods for ring closure. The absolute stereochemistry was elucidated unambiguously by comparison of the analytical data with those of the reported natural product and by single X-ray crystal diffraction of synthetic intermediates. The proposed structure needed to be revised with regard to the absolute configuration of the stereogenic center bearing the secondary hydroxyl group. The reported synthesis offers a flexible, selective, and efficient access to all possible stereoisomers and may be of value for the stereoselective synthesis of other epoxyquinone natural products.

Increasingly sensitive analytical instruments and robust downstream data processing tools have revolutionized natural product research over the past decade. A molecular networking-guided survey led to the identification of 33 new cyclic lipopeptides (CLPs) from the culture broth of the proteobacterium

Hydrogen isotopically labelled compounds are essential diagnostic tools in drug research and development, as they provide vital information about the biological metabolism of drug candidates and their metabolites. Herein we report a photoredox-initiated hydrogen atom transfer (HAT) protocol which efficiently and selectively introduces deuterium or tritium at C(sp3 )-H bonds, utilizing heavy water (D2 O or T2 O) as the hydrogen isotope source, and a guanidine base. This protocol has been successfully applied to the incorporation of deuterium in several amino acids (lysine, glycine and proline) and small peptides. Finally, the method has been applied to tritium, because tritium-labelled peptides are essential for application in biological experiments, such as ligand-binding assays, or absorption, distribution, metabolism, and excretion (ADME) studies.

Armeniaspirols are potent antibiotics containing an unusual spiro[4.4]non-8-ene moiety. Herein, we describe the cloning and functional analysis of the armeniaspirol biosynthetic gene cluster. Gene-inactivation studies and subsequent isolation of previously unknown biosynthetic intermediates shed light on intriguing biosynthetic details. Remarkably, deletion of ams15, which encodes a protein bearing a flavin-binding domain, led to the accumulation of several non-spiro intermediates with various numbers of chlorine substitutions on the pyrrole moiety. The di- and trichloropyrrole species were converted by Streptomyces albus expressing Ams15 into mono- and dichlorinated spiro derivatives, respectively. In addition, in vitro conversion of these non-spiro intermediates into des-N-methyl spiro intermediates by the cell lysate of the same recombinant strain proved Ams15 to be responsible for spiro formation through oxidative dehalogenation.

The spread of multidrug-resistant Gram-negative bacteria is an increasing threat to human health, because novel compound classes for the development of antibiotics have not been discovered for decades. Antimicrobial peptides (AMPs) may provide a much-needed breakthrough because these immunity-related defense molecules protect many eukaryotes against Gram-negative pathogens. Recent concepts in evolutionary immunology predict the presence of potent AMPs in insects that have adapted to survive in habitats with extreme microbial contamination. For example, the saprophagous and coprophagous maggots of the drone fly Eristalis tenax (Diptera) can flourish in polluted aquatic habitats, such as sewage tanks and farmyard liquid manure storage pits. We used next-generation sequencing to screen the E. tenax immunity-related transcriptome for AMPs that are synthesized in response to the injection of bacterial lipopolysaccharide. We identified 22 AMPs and selected nine for larger-scale synthesis to test their activity against a broad spectrum of pathogens, including multidrug-resistant Gram-negative bacteria. Two cecropin-like peptides (EtCec1-a and EtCec2-a) and a diptericin-like peptide (EtDip) displayed strong activity against the pathogens, even under simulated physiological conditions, and also achieved a good therapeutic window. Therefore, these AMPs could be used as leads for the development of novel antibiotics.

Background Peripartum depression and anxiety disorders are highly prevalent and are correlated with adverse maternal and neonatal outcomes. Antenatal care in Germany does not yet include structured screening and effective low-threshold treatment options for women facing peripartum depression and anxiety disorders. Mindfulness-based interventions (MBIs) are increasingly becoming a focus of interest for the management of such patients. Studies have shown a decrease in pregnancy-related stress and anxiety in expectant mothers following mindfulness programs. Objective The aim of this study was to explore the clinical effectiveness of a 1-week electronic course of mindfulness on prenatal depression and anxiety in hospitalized, high-risk pregnant women. We hypothesized that participating in a 1-week electronic MBI (eMBI) could alleviate symptoms of depression and anxiety during the hospital stay. Methods A prospective pilot study with an explorative study design was conducted from January to May 2019 in a sample of 68 women hospitalized due to high-risk pregnancies. After enrolling into the study, the participants were given access to an eMBI app on how to deal with stress, anxiety, and symptoms of depression. Psychometric parameters were assessed via electronic questionnaires comprising the Edinburgh Postnatal Depression Scale (EPDS), State-Trait Anxiety Inventory (STAI-S), and abridged version of the Pregnancy-Related Anxiety Questionnaire (PRAQ-R). Results We observed a high prevalence of peripartum depression and anxiety among hospitalized high-risk pregnant women: 39% (26/67) of the study participants in the first assessment and 41% (16/39) of the participants in the second assessment achieved EPDS scores above the cutoff value for minor/major depression. The number of participants with anxiety levels above the cutoff value (66% [45/68] of the participants in the first assessment and 67% [26/39] of the participants in the second assessment) was significantly more than that of the participants with anxiety levels below the cutoff value, as measured with the STAI-S. After completing the 1-week electronic course on mindfulness, the participants showed a significant reduction in the mean state anxiety levels (P Conclusions Peripartum anxiety and depression represent a relevant health issue in hospitalized pregnant patients. Short-term eMBIs could have the potential to reduce anxiety levels and pregnancy-related anxiety. However, we observed that compliance to eMBI seems to be related to lower symptoms of pregnancy-related stress among high-risk patients. eMBIs represent accessible mental health resources at reduced costs and can be adapted for hospitalized patients during pregnancy.

BACKGROUND Peripartum depression and anxiety disorders are highly prevalent and are correlated with adverse maternal and neonatal outcomes. Antenatal care in Germany does not yet include structured screening and effective low-threshold treatment options for women facing peripartum depression and anxiety disorders. Mindfulness-based interventions (MBIs) are increasingly becoming a focus of interest for the management of such patients. Studies have shown a decrease in pregnancy-related stress and anxiety in expectant mothers following mindfulness programs. OBJECTIVE The aim of this study was to explore the clinical effectiveness of a 1-week electronic course of mindfulness on prenatal depression and anxiety in hospitalized, high-risk pregnant women. We hypothesized that participating in a 1-week electronic MBI (eMBI) could alleviate symptoms of depression and anxiety during the hospital stay. METHODS A prospective pilot study with an explorative study design was conducted from January to May 2019 in a sample of 68 women hospitalized due to high-risk pregnancies. After enrolling into the study, the participants were given access to an eMBI app on how to deal with stress, anxiety, and symptoms of depression. Psychometric parameters were assessed via electronic questionnaires comprising the Edinburgh Postnatal Depression Scale (EPDS), State-Trait Anxiety Inventory (STAI-S), and abridged version of the Pregnancy-Related Anxiety Questionnaire (PRAQ-R). RESULTS We observed a high prevalence of peripartum depression and anxiety among hospitalized high-risk pregnant women: 39% (26/67) of the study participants in the first assessment and 41% (16/39) of the participants in the second assessment achieved EPDS scores above the cutoff value for minor/major depression. The number of participants with anxiety levels above the cutoff value (66% [45/68] of the participants in the first assessment and 67% [26/39] of the participants in the second assessment) was significantly more than that of the participants with anxiety levels below the cutoff value, as measured with the STAI-S. After completing the 1-week electronic course on mindfulness, the participants showed a significant reduction in the mean state anxiety levels (PP CONCLUSIONS Peripartum anxiety and depression represent a relevant health issue in hospitalized pregnant patients. Short-term eMBIs could have the potential to reduce anxiety levels and pregnancy-related anxiety. However, we observed that compliance to eMBI seems to be related to lower symptoms of pregnancy-related stress among high-risk patients. eMBIs represent accessible mental health resources at reduced costs and can be adapted for hospitalized patients during pregnancy.

The spread of antibiotic-resistant human pathogens and the declining number of novel antibiotics in the development pipeline is a global challenge that has fueled the demand for alternative options. The search for novel drug candidates has expanded to include not only antibiotics but also adjuvants capable of restoring antibiotic susceptibility in multidrug-resistant (MDR) pathogens. Insect-derived antimicrobial peptides (AMPs) can potentially fulfil both of these functions. We tested two coleoptericins and one coleoptericin-like peptides from the invasive harlequin ladybird Harmonia axyridis against a panel of human pathogens. The AMPs displayed little or no activity when tested alone but were active even against clinical MDR isolates of the Gram-negative ESKAPE strains when tested in combination with polymyxin derivatives, such as the reserve antibiotic colistin, at levels below the minimal inhibitory concentration. Assuming intracellular targets of the AMPs, our data indicate that colistin potentiates the activity of the AMPs. All three AMPs achieved good in vitro therapeutic indices and high intrahepatic stability but low plasma stability, suggesting they could be developed as adjuvants for topical delivery or administration by inhalation for anti-infective therapy to reduce the necessary dose of colistin (and thus its side effects) or to prevent development of colistin resistance in MDR pathogens.

Telomycin (TEM) is a cyclic depsipeptide antibiotic active against Gram-positive bacteria. In this study, five new natural telomycin analogues produced by Streptomyces canus ATCC 12646 were identified. To understand the biosynthetic machinery of telomycin and to generate more analogues by pathway engineering, the TEM biosynthesis gene cluster has been characterized from S. canus ATCC 12646: it spans approximately 80.5 kb and consists of 34 genes encoding fatty acid ligase, nonribosomal peptide synthetases (NRPSs), regulators, transporters, and tailoring enzymes. The gene cluster was heterologously expressed in Streptomyces albus J1074 setting the stage for convenient biosynthetic engineering, mutasynthesis, and production optimization. Moreover, in-frame deletions of one hydroxylase and two P450 monooxygenase genes resulted in the production of novel telomycin derivatives, revealing these genes to be responsible for the specific modification by hydroxylation of three amino acids found in the TEM backbone. Surprisingly, natural lipopeptide telomycin precursors were identified when characterizing an unusual precursor deacylation mechanism during telomycin maturation. By in vivo gene inactivation and in vitro biochemical characterization of the recombinant enzyme Tem25, the maturation process was shown to involve the cleavage of previously unknown telomycin precursor-lipopeptides, to yield 6-methylheptanoic acid and telomycins. These lipopeptides were isolated from an inactivation mutant of tem25 encoding a (de)acylase, structurally elucidated, and then shown to be deacylated by recombinant Tem25. The TEM precursor and several semisynthetic lipopeptide TEM derivatives showed rapid bactericidal killing and were active against several multidrug-resistant (MDR) Gram-positive pathogens, opening the path to future chemical optimization of telomycin for pharmaceutical application.

New for old—TB drug development Tuberculosis (TB) is a global health threat for which there is only lengthy drug treatment. Patients need to consume multiple tablets over several months and frequently fail to complete their treatment. Consequently, drug-resistant strains of the pathogen have emerged, which add to the threat. Kling et al. revisited a natural product called griselimycin, extracted from the same organism that produced the prototype anti-TB drug, streptomycin. Unmodified griselimycin has poor pharmacological properties. However, one synthetic derivative had improved oral uptake and penetrated cells of the immune system that harbor the TB mycobacterium. In combination with other drugs, the griselimycin derivative showed high potency in mice with TB. Science , this issue p. 1106

Microbial natural products are a rich source of bioactive molecules to serve as drug leads and/or biological tools. We investigated a little-explored myxobacterial genus, Nannocystis sp., and discovered a novel 21-membered macrocyclic scaffold that is composed of a tripeptide and a polyketide part with an epoxyamide moiety. The relative and absolute configurations of the nine stereocenters was determined by NMR spectroscopy, molecular dynamics calculations, chemical degradation, and X-ray crystallography. The compound, named nannocystin A (1), was found to inhibit cell proliferation at low nanomolar concentrations through the early induction of apoptosis. The mode of action of 1 could not be matched to that of standard drugs by transcriptional profiling and biochemical experiments. An initial investigation of the structure-activity relationship based on seven analogues demonstrated the importance of the epoxide moiety for high activity.

A series of imidazo[1,2-a]indeno[1,2-e]pyrazin-4-ones that potently inhibit M. tuberculosis glutamine synthetase (GlnA1) has been identified by high throughput screening. Exploration of this series was performed owing to a short chemistry program. Despite possibly nanomolar inhibitions, none of these compounds was active on whole cell Mtb, suggesting that GlnA1 may not be a suitable target to find new anti-tubercular drugs.

The total synthesis of the naturally occurring antibiotic GE81112A, a densely functionalized tetrapeptide, is reported. Comparison of spectral data with those of the natural product and the lack of biological activity of the synthesized compound led us to revise the published configuration of the 3‐hydroxypipecolic acid moiety. This hypothesis was fully validated by the synthesis of the corresponding epimer.

The spread of antibiotic-resistant human pathogens and the declining number of novel antibiotics in the development pipeline is a global challenge that has fueled the demand for alternative options. The search for novel drug candidates has expanded to include not only antibiotics but also adjuvants capable of restoring antibiotic susceptibility in multidrug-resistant (MDR) pathogens. Insect-derived antimicrobial peptides (AMPs) can potentially fulfil both of these functions. We tested two coleoptericins and one coleoptericin-like peptides from the invasive harlequin ladybird Harmonia axyridis against a panel of human pathogens. The AMPs displayed little or no activity when tested alone but were active even against clinical MDR isolates of the Gram-negative ESKAPE strains when tested in combination with polymyxin derivatives, such as the reserve antibiotic colistin, at levels below the minimal inhibitory concentration. Assuming intracellular targets of the AMPs, our data indicate that colistin potentiates the activity of the AMPs. All three AMPs achieved good in vitro therapeutic indices and high intrahepatic stability but low plasma stability, suggesting they could be developed as adjuvants for topical delivery or administration by inhalation for anti-infective therapy to reduce the necessary dose of colistin (and thus its side effects) or to prevent development of colistin resistance in MDR pathogens.

Covering: up to March 2013 In addition to their prominent role in basic biological and chemical research, natural products are a rich source of commercial products for the pharmaceutical and other industries. Industrial natural product chemistry is of fundamental importance for successful product development, as the vast majority (ca. 80%) of commercial drugs derived from natural products require synthetic efforts, either to enable economical access to bulk material, and/or to optimize drug properties through structural modifications. This review aims to illustrate issues on the pathway from lead to product, and how they have been successfully addressed by modern natural product chemistry. It is focused on natural products of current relevance that are, or are intended to be, used as pharmaceuticals.

Summary In vitro reconstitution and biochemical analysis of natural product biosynthetic pathways remains a challenging endeavor, especially if megaenzymes of the nonribosomal peptide synthetase (NRPS) type are involved. In theory, all biosynthetic steps may be deciphered using mass spectrometry (MS)-based analyses of both the carrier protein-coupled intermediates and the free intermediates. We here report the "total biosynthesis" of the pyrrolo[4,2]benzodiazepine scaffold tomaymycin using an in vitro reconstituted NRPS system. Proteoforms were analyzed by liquid chromatography (LC)-MS to decipher every step of the biosynthesis on its respective megasynthetase with up to 170 kDa in size. To the best of our knowledge, this is the first report of a comprehensive analysis of virtually all chemical steps involved in the biosynthesis of nonribosomally synthesized natural products. The study includes experiments to determine substrate specificities of the corresponding A-domains in competition assays by analyzing the adenylation step as well as the transfer to the respective carrier protein domain.

Seven new halogenated peptides termed svetamycins A-G (1-7) have been isolated from laboratory cultures of a Streptomyces sp. Svetamycins A-D, F, and G are cyclic depsipeptides, whereas svetamycin E is a linear analogue of svetamycin C. Their structures were determined using extensive spectroscopic analysis, and their stereochemical configuration was established by a combination of NMR data, quantum mechanical calculations, and chemical derivatizations. Svetamycins are characterized by the presence of a hydroxyl acetic acid and five amino acids including a rare 4,5-dihydroxy-2,3,4,5-tetrahydropyridazine-3-carboxylic acid, a g-halogenated piperazic acid, and a novel d-methylated piperazic acid in svetamycins B-C, E, and G. Moreover, isotope-labeled substrate feeding experiments demonstrated ornithine as the precursor of piperazic acid and that methylation at the d position of the piperazyl scaffold is S-adenosyl-l-methionine (SAM)-dependent. Svetamycin G, the most potent antimicrobial of this suite of compounds, inhibited the growth of Mycobacterium smegmatis with an MIC80 value of 2 mg/mL.

Griselimycin (GM) and methylgriselimycin (MGM), naturally produced by microorganisms of the genus Streptomyces, are cyclic depsipeptides composed of ten amino acids. They exhibit antibacterial activity against mycobacterium species by inhibiting the sliding clamp of prokaryotic DNA polymerase III and are therefore considered as potential anti-tuberculosis drugs. The difference between both peptides is the presence of L -(R)-4-methylproline in MGM instead of L -proline in GM at position 8 of the amino acid sequence. Methylation increases both metabolic stability and activity of MGM compared to GM. To get deeper insight into the structure-activity relationship we determined the solution structure of the cyclic part of methylgriselimycin using rotating frame nuclear Overhauser effect (ROE) distance restraints and residual dipolar couplings (RDC). The structure of methylgriselimycin in solution is compared to the structure of griselimycin in a co-crystal with DNA polymerase III subunit beta. As a result a highly defined structural model of methylgriselimycin is obtained which shows related characteristics to the bound griselimycin.

Mature thrombin activatable fibrinolysis inhibitor (TAFIa) is a carboxypeptidase that stabilizes fibrin clots by removing C-terminal arginines and lysines from partially degraded fibrin. Inhibition of TAFIa stimulates the degradation of fibrin clots and may help to prevent thrombosis. Applying a lead finding approach based on literature-mining, we discovered that anabaenopeptins, cyclic peptides produced by cyanobacteria, were potent inhibitors of TAFIa with IC50 values as low as 1.5 nM. We describe the isolation and structure elucidation of 20 anabaenopeptins, including 13 novel congeners, as well as their pronounced structure-activity relationships (SAR) with respect to inhibition of TAFIa. Crystal structures of the anabaenopeptins B, C and F bound to the surrogate protease carboxypeptidase B revealed the binding modes of these large (~850 Da) compounds in detail and explained the observed SAR, i.e. the strong dependence of the potency on a basic (Arg, Lys) exocyclic residue that addressed the S1’ binding pocket, and a broad tolerance towards substitutions in the pentacyclic ring that acted as a plug of the active site.

A high throughput phenotypic screening against Mycobacterium smegmatis led us to the discovery of a new class of bacteriostatic, highly hydrophobic antitubercular quinazolinones that potently inhibited the in vitro growth of either extracellular or intramacrophagic M. tuberculosis (Mtb), via modulation of an unidentified but yet novel target. Optimization of the initial hit compound culminated in the identification of potent but poorly soluble Mtb growth inhibitors, three of which were progressed to in vivo efficacy studies. Despite nanomolar in vitro potency and attractive PK properties, none of these compounds was convincingly potent in our in vivo mouse tuberculosis models. This lack of efficacy may be linked to the poor drug-likeness of the test molecules and/or to the properties of the target.

In an antibiotic lead discovery program, the known strain Streptomyces armeniacus DSM19369 has been found to produce three new natural products when cultivated on a malt-containing medium. The challenging structural elucidation of the isolated compounds was achieved by using three independent methods, that is, chemical degradation followed by NMR spectroscopy, a computer-assisted structure prediction algorithm, and X-ray crystallography. The compounds, named armeniaspirol A-C (2-4), exhibit a compact, hitherto unprecedented chlorinated spiro[4.4]non-8-ene scaffold. Labeling experiments with [1-(13)C] acetate, [1,2-(13)C2] acetate, and [U-(13)C] proline suggest a biosynthesis through a rare two-chain mechanism. Armeniaspirols displayed moderate to high in vitro activities against gram-positive pathogens such as methicillin-resistant S. aureus (MRSA) or vancomycin resistant E. faecium (VRE). As analogue 2 was active in vivo in an MRSA sepsis model, and showed no development of resistance in a serial passaging experiment, it represents a new antibiotic lead structure.