Randomized controlled phase 2 trial of hydroxychloroquine in childhood interstitial lung disease

Background No results of controlled trials are available for any of the few treatments offered to children with interstitial lung diseases (chILD). We evaluated hydroxychloroquine (HCQ) in a phase 2, prospective, multicentre, 1:1-randomized, double-blind, placebo-controlled, parallel-group/crossover trial. HCQ (START arm) or placebo were given for 4 weeks. Then all subjects received HCQ for another 4 weeks. In the STOP arm subjects already taking HCQ were randomized to 12 weeks of HCQ or placebo (= withdrawal of HCQ). Then all subjects stopped treatment and were observed for another 12 weeks. Results 26 subjects were included in the START arm, 9 in the STOP arm, of these four subjects participated in both arms. The primary endpoint, presence or absence of a response to treatment, assessed as oxygenation (calculated from a change in transcutaneous O 2 -saturation of ≥ 5%, respiratory rate ≥ 20% or level of respiratory support), did not differ between placebo and HCQ groups. Secondary endpoints including change of O 2 -saturation ≥ 3%, health related quality of life, pulmonary function and 6-min-walk-test distance, were not different between groups. Finally combining all placebo and all HCQ treatment periods did not identify significant treatment effects. Overall effect sizes were small. HCQ was well tolerated, adverse events were not different between placebo and HCQ. Conclusions Acknowledging important shortcomings of the study, including a small study population, the treatment duration, lack of outcomes like lung function testing below age of 6 years, the small effect size of HCQ treatment observed requires careful reassessments of prescriptions in everyday practice (EudraCT-Nr.: 2013-003714-40, www.clinicaltrialsregister.eu , registered 02.07.2013)

Recent advances in the field of bioactive tetronates

Covering: up to mid-2014 Over the last several decades, the number of pharmacologically active natural products has significantly increased and several natural product families have taken shape. This review highlights the family of tetronate and spirotetronate compounds, which show a vast structural and functional diversity. The rapid growth of this group has created the need for a comprehensive overview and classification system, which we have devised based on structural characteristics. An updated overview is provided based on known tetronates, intended to spur further research in this field by identifying common structural features and general principles of their biosynthesis. We also compare a selection of chemical syntheses of representative compounds belonging to individual subtypes, both in terms of their efficiency as well as the extent to which they are biomimetic. This review also summarizes progress in unraveling some of the principles underlying the potent and varied bioactivities of natural tetronate antibiotics, and in identifying and better understanding their structure–activity relationships and modes of action.DFG, EXC 314, Unifying Concepts in Catalysi

The albicidin resistance factor AlbD is a serine endopeptidase that hydrolyzes unusual oligoaromatic-type peptides

The para-aminobenzoic acid-containing peptide albicidin is a pathogenicity factor synthesized by Xanthomonas albilineans in infections of sugar cane. Albicidin is a nanomolar inhibitor of the bacterial DNA gyrase with a strong activity against various Gram-negative bacteria. The bacterium Pantoea dispersa expresses the hydrolase AlbD, conferring natural resistance against albicidin. We show that AlbD is a novel type of endopeptidase that catalyzes the cleavage of albicidin at a peptide backbone amide bond, thus abolishing its antimicrobial activity. Additionally, we determined the minimal cleavage motif of AlbD with substrates derived by chemical synthesis. Our results clearly identify AlbD as a unique endopeptidase that is the first member of a new subfamily of peptidases. Our findings provide the molecular basis for a natural detoxification mechanism, potentially rendering a new tool in biological chemistry approaches. (Résumé d'auteur

Full elucidation of the hitherto unknown structure of albicidin, a potent antibiotic produced by Xanthomonas albilineans

Albicidin is a potent DNA gyrase inhibitor produced by the sugarcane pathogenic bacterium Xanthomonas albilineans. As such, this molecule blocks the differentiation of chloroplasts, resulting in appearance of narrow white stripes on sugarcane leaves that are characteristic of leaf scald disease. Albicidin targets the bacterial gyrase by a mechanism that is different from the one of other DNA gyrases inhibitors like coumarins or quinolones [1]. It also exhibits antibacterial activity at nanomolar concentrations against Escherichia coli and to a lower extent against numerous Gram-negative and -positive human pathogenic bacteria [2].A decade of intense work was necessary to decipher albicidin's biosynthetic pathway and to elucidate its astonishing never-seen-before structure. Albicidin is produced by a hybrid PKS/NRPS (polyketide synthase/non ribosomal peptide synthetase) system. Such ribosome-independent systems consist of modular megasynthetases which operate in an assembly-line fashion to activate, modify and link mostly unusual aminoacid building blocks, finally resulting in complex bioactive peptide-like molecules. The structure of albicidin, which was predicted by former in silico sequence analyses of its PKS/NRPS gene cluster [3], was ascertained by means of mass spectrometry and nuclear magnetic resonance spectroscopy. We were able to demonstrate that albicidin exhibits a linear polyaromatic penta-peptidic structure containing the rare aminoacids para-aminobenzoate and cyanoalanine [4]. The determination of the structure of albicidin allowed the development of a protocol for the chemical synthesis of this complex molecule. Consequently, new research, such as structure-activity relationship studies, will now be possible [5].New insights into biosynthesis pathway and structural determination for albicidin will be presented. (Texte intégral

The gyrase inhibitor albicidin consists of p-aminobenzoic acids and cyanoalanine

Albicidin is a potent DNA gyrase inhibitor produced by the sugarcane pathogenic bacterium Xanthomonas albilineans. Here we report the elucidation of the hitherto unknown structure of albicidin, revealing a unique polyaromatic oligopeptide mainly composed of p-aminobenzoic acids. In vitro studies provide further insights into the biosynthetic machinery of albicidin. These findings will enable structural investigations on the inhibition mechanism of albicidin and its assessment as a highly effective antibacterial drug. (Résumé d'auteur

Full elucidation of the hitherto unknown structure of albicidin, a potent antibiotic produced by Xanthomonas albilineans

Albicidin is a potent DNA gyrase inhibitor produced by the sugarcane pathogenic bacterium Xanthomonas albilineans. As such, this molecule blocks the differentiation of chloroplasts, resulting in appearance of narrow white stripes on sugarcane leaves that are characteristic of leaf scald disease. Albicidin targets the bacterial gyrase by a mechanism that is different from the one of other DNA gyrases inhibitors like coumarins or quinolones [ 1). lt also exhibits antibacterial activity at nanomolar concentrations against Escherichia coti and to a lower extent against numerous Gram-negative and -positive human pathogenic bacteria [2]. A decade of intense work was necessary to decipher albicidin's biosynthetic pathway and to elucidate its astonishing never-seen-before structure. Albicidin is produced by a hybrid PKS/NRPS (polyketide synthase/non ribosomal peptide synthetase) system. Such ribosome- independent systems consist of modular megasynthetases which operate in an assembly-line fashion to activate, modify and link mostly unusual aminoacid bui lding blocks, finally resulting in complex bioactive peptide-like molecules. The structure of albicid in, which was predicted by former in silico sequence analyses of its PKS/N RPS gene cluster [3], was ascertained by means of mass spectrometry and nuclear magnetic resonance spectroscopy. We were able to demonstrate that albicidin exhibits a linear polyaromatic penta-peptid ic structure containing the rare aminoacids paraaminobenzoate and cyanoalanine [4]. The determination of the structure of albicidin allowed the development of a protocol for the chemical synthesis of this complex molecule. Consequently, new research, such as structure-activity relationship studies, will now be possible [5]. New insights into biosynthesis pathway and structural determination for albicidin will be presented. (Résumé d'auteur

Full elucidation of the hitherto unknown structure of albicidin, a potent antibiotic produced by Xanthomonas albilineans

Albicidin is a potent DNA gyrase inhibitor produced by the sugarcane pathogenic bacterium Xanthomonas albilineans. As such, this molecule blocks the differentiation of chloroplasts, resulting in appearance of narrow white stripes on sugarcane leaves that are characteristic of leaf scald disease. Albicidin targets the bacterial gyrase by a mechanism that is different from the one of other DNA gyrases inhibitors like coumarins or quinolones [1]. It also exhibits antibacterial activity at nanomolar concentrations against Escherichia coli and to a lower extent against numerous Gram-negative and -positive human pathogenic bacteria [2].A decade of intense work was necessary to decipher albicidin's biosynthetic pathway and to elucidate its astonishing never-seen-before structure. Albicidin is produced by a hybrid PKS/NRPS (polyketide synthase/non ribosomal peptide synthetase) system. Such ribosome-independent systems consist of modular megasynthetases which operate in an assembly-line fashion to activate, modify and link mostly unusual aminoacid building blocks, finally resulting in complex bioactive peptide-like molecules. The structure of albicidin, which was predicted by former in silico sequence analyses of its PKS/NRPS gene cluster [3], was ascertained by means of mass spectrometry and nuclear magnetic resonance spectroscopy. We were able to demonstrate that albicidin exhibits a linear polyaromatic penta-peptidic structure containing the rare aminoacids para-aminobenzoate and cyanoalanine [4]. The determination of the structure of albicidin allowed the development of a protocol for the chemical synthesis of this complex molecule. Consequently, new research, such as structure-activity relationship studies, will now be possible [5].New insights into biosynthesis pathway and structural determination for albicidin will be presented. (Texte intégral