Olga Genilloud - Academia.edu (original) (raw)

Papers by Olga Genilloud

BioMed Research International, 2015

Concern over the reports of antibiotic-resistant bacterial infections in hospitals and in the com... more Concern over the reports of antibiotic-resistant bacterial infections in hospitals and in the community has been publicized in the media, accompanied by comments on the risk that we may soon run out of antibiotics as a way to control infectious disease. Infections caused byEnterococcus faecium, Staphylococcus aureus, Klebsiellaspecies,Clostridium difficile, Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli, and otherEnterobacteriaceaespecies represent a major public health burden. Despite the pharmaceutical sector’s lack of interest in the topic in the last decade, microbial natural products continue to represent one of the most interesting sources for discovering and developing novel antibacterials. Research in microbial natural product screening and development is currently benefiting from progress that has been made in other related fields (microbial ecology, analytical chemistry, genomics, molecular biology, and synthetic biology). In this paper, we review how no...

International Journal of Molecular Sciences

Sleeping sickness or African trypanosomiasis is a serious health concern with an added socio-econ... more Sleeping sickness or African trypanosomiasis is a serious health concern with an added socio-economic impact in sub-Saharan Africa due to direct infection in both humans and their domestic livestock. There is no vaccine available against African trypanosomes and its treatment relies only on chemotherapy. Although the current drugs are effective, most of them are far from the modern concept of a drug in terms of toxicity, specificity and therapeutic regime. In a search for new molecules with trypanocidal activity, a high throughput screening of 2000 microbial extracts was performed. Fractionation of one of these extracts, belonging to a culture of the fungus Amesia sp., yielded a new member of the curvicollide family that has been designated as curvicollide D. The new compound showed an inhibitory concentration 50 (IC50) 16-fold lower in Trypanosoma brucei than in human cells. Moreover, it induced cell cycle arrest and disruption of the nucleolar structure. Finally, we showed that cu...

Antibiotics, 2020

An antifungal lipodepsipeptide was obtained from cultures of the fungus Foliophoma fallens CF-236... more An antifungal lipodepsipeptide was obtained from cultures of the fungus Foliophoma fallens CF-236885. Its structure, elucidated by HRMS and NMR spectroscopy, contained Gly, Thr, Asn, β-Ala, Orn, Ala, two Ser residues, and 3-hydroxy-4-methylhexadecanoic acid. The absolute configuration of its amino acid residues was determined using Marfey’s analysis and J-based configuration analysis helped to establish the relative configuration of the 3-hydroxy-4-methylhexadecanoic acid moiety. A literature search retrieved a patent describing antibiotic TKR2999 (1), whose non-disclosed structure was confirmed to be identical to that found for our compound, according to its physicochemical properties and NMR spectra. Compound 1 displayed potent antifungal activity against Aspergillus fumigatus and a panel of Candida strains.

Marine Drugs, 2019

As part of our continuing efforts to discover new bioactive compounds from microbial sources, a r... more As part of our continuing efforts to discover new bioactive compounds from microbial sources, a reinvestigation of extracts of scaled-up cultures of the marine-derived Streptomyces sp. strain CA-271078 resulted in the isolation and structural elucidation of four new napyradiomycins (1–3, 5). The known napyradiomycin SC (4), whose structural details had not been previously described in detail, and another ten related known compounds (6–15). The structures of the new napyradiomycins were characterized by HRMS and 1D- and 2D-NMR spectroscopies and their relative configurations were established through a combination of molecular modelling with nOe and coupling constants NMR analysis. The absolute configuration of each compound is also proposed based on biosynthetic arguments and the comparison of specific rotation data with those of related compounds. Among the new compounds, 1 was determined to be the first non-halogenated member of napyradiomycin A series containing a functionalized p...

Metabolites, 2019

Fungi are one of the most prolific sources of microbial secondary metabolites. The production of ... more Fungi are one of the most prolific sources of microbial secondary metabolites. The production of new metabolites can be achieved using multiple fermentation conditions and by adding small-molecule effectors, including epigenetic modifiers. In the framework of our Natural Product screening programme targeting the discovery of new antimicrobial compounds, we applied multiple fermentation conditions and adsorptive polymeric resins on a large collection of fungal endophytes, to increase and stimulate their fungal secondary metabolite production. During this work the endophytic fungus Dimorphosporicola tragani CF-090383 showed antimicrobial activity only when grown in presence of adsorptive polymeric resins. In addition, seven epigenetic modifiers were added to fermentations of this endophytic fungus, in an attempt to activate its cryptic pathways as well as to analyse the metabolites produced under these conditions. D. tragani was seen to produce three different mycotoxin dendrodolides ...

Antibiotics, 2018

The current spread of multi-drug resistance in a number of key pathogens and the lack of therapeu... more The current spread of multi-drug resistance in a number of key pathogens and the lack of therapeutic solutions in development to address most of the emerging infections in the clinic that are difficult to treat have become major concerns. Microbial natural products represent one of the most important sources for the discovery of potential new antibiotics and actinomycetes have been one of the most relevant groups that are prolific producers of these bioactive compounds. Advances in genome sequencing and bioinformatic tools have collected a wealth of knowledge on the biosynthesis of these molecules. This has revealed the broad untapped biosynthetic diversity of actinomycetes, with large genomes and the capacity to produce more molecules than previously estimated, opening new opportunities to identify the novel classes of compounds that are awaiting to be discovered. Comparative genomics, metabolomics and proteomics and the development of new analysis and genetic engineering tools pro...

Biology and Biotechnology of Actinobacteria, 2017

The use of general descriptive names, registered names, trademarks, service marks, etc. in this p... more The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Scientific reports, Jan 27, 2018

Native plant communities from arid areas present distinctive characteristics to survive in extrem... more Native plant communities from arid areas present distinctive characteristics to survive in extreme conditions. The large number of poorly studied endemic plants represents a unique potential source for the discovery of novel fungal symbionts as well as host-specific endophytes not yet described. The addition of adsorptive polymeric resins in fungal fermentations has been seen to promote the production of new secondary metabolites and is a tool used consistently to generate new compounds with potential biological activities. A total of 349 fungal strains isolated from 63 selected plant species from arid ecosystems located in the southeast of the Iberian Peninsula, were characterized morphologically as well as based on their ITS/28S ribosomal gene sequences. The fungal community isolated was distributed among 19 orders including Basidiomycetes and Ascomycetes, being Pleosporales the most abundant order. In total, 107 different genera were identified being Neocamarosporium the genus mo...

Marine drugs, Jan 16, 2018

Phocoenamicins B and C (and), together with the known spirotetronate phocoenamicin (), were isola... more Phocoenamicins B and C (and), together with the known spirotetronate phocoenamicin (), were isolated from cultures ofsp. The acetone extract from a culture of this strain, isolated from marine sediments collected in the Canary Islands, displayed activity against methicillin-resistant(MRSA),H37Ra and. Bioassay-guided fractionation of this extract using SP207ss column chromatography and preparative reversed-phased HPLC led to the isolation of the new compoundsandbelonging to the spirotetronate class of polyketides. Their structures were determined using a combination of HRMS, 1D and 2D NMR experiments and comparison with the spectra reported for phocoenamicin. Antibacterial activity tests of the pure compounds against these pathogens revealed minimal inhibitory concentration (MIC) values ranging from 4 to 64 µg/mL for MRSA, and 16 to 32 µg/mL forH37Ra, with no significant activity found againstand vancomycin-resistant(VRE) at concentrations below 128 µg/mL, and weak activity detected ...

Natural Product Reports, 2017

An update on last ten years of actinomycetes antibiotic discovery, including recent key molecules... more An update on last ten years of actinomycetes antibiotic discovery, including recent key molecules in clinical development and overlooked compounds discovered using novel strategies.

Frontiers in pharmacology, 2017

Nitric-oxide synthase, the enzyme responsible for mammalian nitric oxide generation, and cytochro... more Nitric-oxide synthase, the enzyme responsible for mammalian nitric oxide generation, and cytochrome P450, the major enzymes involved in drug metabolism, share striking similarities. Therefore, it makes sense that cytochrome P450 drug mediated biotransformations might play an important role in the pharmacological modulation of nitric oxide synthase. In this work, we have undertaken an integrated in vitro assessment of the hepatic metabolism and nitric oxide modulation of previously described dual inhibitors (imidazoles and macrolides) of these enzymes in order assess the implication of CYP450 activities over production of nitric oxide. In vitro systems based in human liver microsomes and activated mouse macrophages were developed for these purposes. Additionally in vitro production the hepatic metabolites of dual inhibitor, roxithromycin, was investigated achieving the identification and isolation of main hepatic biotransformation products. Our results suggested that for some macroli...

Frontiers in microbiology, 2017

In this report, we describe a High-Throughput Screening (HTS) to identify compounds that inhibit ... more In this report, we describe a High-Throughput Screening (HTS) to identify compounds that inhibit biofilm formation or cause the disintegration of an already formed biofilm using the Salmonella Enteritidis 3934 strain. Initially, we developed a new methodology for growing Salmonella biofilms suitable for HTS platforms. The biomass associated with biofilm at the solid-liquid interface was quantified by staining both with resazurin and crystal violet, to detect living cells and total biofilm mass, respectively. For a pilot project, a subset of 1120 extracts from the Fundación MEDINA's collection was examined to identify molecules with antibiofilm activity. This is the first validated HTS assay of microbial natural product extracts which allows for the detection of four types of activities which are not mutually exclusive: inhibition of biofilm formation, detachment of the preformed biofilm and antimicrobial activity against planktonic cells or biofilm embedded cells. Currently, sev...

Frontiers in microbiology, 2017

Ramoplanin is a glycolipodepsipeptide antibiotic obtained from fermentation of Actinoplanes sp. A... more Ramoplanin is a glycolipodepsipeptide antibiotic obtained from fermentation of Actinoplanes sp. ATCC 33076 that exhibits activity against clinically important multi-drug-resistant, Gram-positive pathogens including vancomycin-resistant Enterococcus (VRE), methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-intermediate resistant Clostridium difficile. It disrupts bacterial cell wall through a unique mechanism of action by sequestering the peptidoglycan intermediate Lipid II and therefore does not show cross-resistance with other antibiotics. However, while demonstrating excellent antimicrobial activity in systemic use in animal models of infection, ramoplanin presents low local tolerability when injected intravenously. As a consequence of this limitation, new derivatives are desirable to overcome this issue. During a natural product screening program developed to discover compounds that disrupt bacterial cell wall synthesis by inhibiting peptidoglycan transglycosylati...

Journal of Natural Products, 2017

S1 Overlapped HSQC spectra of hormonemate B (2) and erythritol, showing the 'alditol' region. Blu... more S1 Overlapped HSQC spectra of hormonemate B (2) and erythritol, showing the 'alditol' region. Blue and red signals correspond to hormonemate B whereas green and pink are those of a standard of erythritol. S2 Overlapped HSQC spectra of hormonemate (5) and D-mannitol, showing the 'alditol' region. Blue and red signals correspond to hormonemate whereas green and pink are those of a standard of D-mannitol. S3 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate A (1). S4 Zoom shot of the 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate A (1). S5 13 C-NMR (125 MHz, methanol-d4) spectrum of hormonemate A (1). S6 HSQC (methanol-d4) spectrum of hormonemate A (1). S7 HMBC (methanol-d4) spectrum of hormonemate A (1). S8 COSY (methanol-d4) spectrum of hormonemate A (1). S9 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate B (2). S10 Zoom shot of the 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate B (2). S11 13 C-NMR (125 MHz, methanol-d4) spectrum of hormonemate B (2). S12 HSQC (methanol-d4) spectrum of hormonemate B (2). S13 HMBC (methanol-d4) spectrum of hormonemate B (2). S14 COSY (methanol-d4) spectrum of hormonemate B (2). S15 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate C (3). S16 Zoom shot of the 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate C (3). S17 13 C-NMR (125 MHz, methanol-d4) spectrum of hormonemate C (3). S18 HSQC (methanol-d4) spectrum of hormonemate C (3). S19 HMBC (methanol-d4) spectrum of hormonemate C (3). S20 COSY (methanol-d4) spectrum of hormonemate C (3). S21 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate D (4). S22 Zoom shot of the 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate D (4). S23 13 C-NMR (125 MHz, methanol-d4) spectrum of hormonemate D (4). S24 HSQC (methanol-d4) spectrum of hormonemate D (4). S25 HMBC (methanol-d4) spectrum of hormonemate D (4). S26 COSY (methanol-d4) spectrum of hormonemate D (4). S27 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate (5). S28 Zoom shot of the 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate (5). S29 13 C-NMR (125 MHz, methanol-d4) spectrum of hormonemate (5). S30 HSQC (methanol-d4) spectrum of hormonemate (5). S31 HMBC (methanol-d4) spectrum of hormonemate (5). S32 COSY (methanol-d4) spectrum of hormonemate (5). S33 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate E (6). S34 Zoom shot of the 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate E (6). S35 13 C-NMR (125 MHz, methanol-d4) spectrum of hormonemate E (6). S36 HSQC (methanol-d4) spectrum of hormonemate E (6). S37 HMBC (methanol-d4) spectrum of hormonemate E (6). S38 COSY (methanol-d4) spectrum of hormonemate E (6).

Marine Drugs, 2016

A new napyradiomycin, MDN-0170 (1), was isolated from the culture broth of the marine-derived act... more A new napyradiomycin, MDN-0170 (1), was isolated from the culture broth of the marine-derived actinomycete strain CA-271078, together with three known related compounds identified as 4-dehydro-4a-dechloronapyradiomycin A1 (2), napyradiomycin A1 (3) and 3-chloro-6,8-dihydroxy-8-α-lapachone (4). The structure of the new compound was determined using a combination of spectroscopic techniques, including 1D and 2D NMR and electrospray-time of flight mass spectrometry (ESI-TOF MS). The relative configuration of compound 1, which contains two independent stereoclusters, has been established by molecular modelling in combination with nOe and coupling constant analyses. Biosynthetic arguments also allowed us to propose its absolute stereochemistry. The antimicrobial properties of the compounds isolated were evaluated against methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, Aspergillus fumigatus, and Candida albicans. The potent bioactivity previously reported for compounds 2 and 3 against methicillin-sensitive S. aureus has been extended to methicillin-resistant strains in this report.

Planta medica, Jan 5, 2016

During a high-throughput screening program focused on the discovery and characterization of new a... more During a high-throughput screening program focused on the discovery and characterization of new antifungal compounds, a total of 8320 extracts from Fundacion MEDINA's collection were screened against a panel of 6 fungal parasitic strains, namely Candida glabrata, Candida krusei, Candida parapsilosis, Candida tropicalis, Candida albicans, and Aspergillus fumigatus. A total of 127 extracts displayed antifungal properties and, after LC/MS dereplication, 10 were selected for further fractionation. Bioassay-guided fractionation from a 1-L fermentation of one of these extracts, belonging to the fungus Chaetopsina sp., led to the isolation of linoleyl sulphate (1), linolenyl sulphate (2), and oleyl sulphate (3) as the compounds responsible for the antifungal activity. These molecules were previously described as synthetic products with the ability to produce the allosteric inhibition of soybean lipoxygenase and human lipoxygenase.

Current Microbiology, 2016

Fifty four isolates of actinomycetes were collected from four different rhizospheric soils: 18 st... more Fifty four isolates of actinomycetes were collected from four different rhizospheric soils: 18 strains from palm tree bark and soil, 12 strains from an olive field soil, 9 strains from a coastal forest, and 15 strains from an agriculture soil situated in the Algerian-Tunisian border (Oum Tboul). Based on morphological and cultural characters, the isolates were classified as Streptomyces (42 strains), Micromonospora (4 strains), Pseudonocardia (1 strain), Actinomadura (1 strain), Nocardia (1 strain), and non-Streptomyces (5 strains). More than half of the isolates inhibited at least one tested pathogenic microorganisms in liquid culture. In addition, antimicrobial activities of some strains were tested on solid culture. Several bioactive compounds were identified by liquid chromatography joined with low-resolution mass spectroscopy (LC/MS) and analysed by MEDINA's database and by the dictionary of natural products Chapman & Hall. An interesting chlorinated compound with the molecular formula C20H37ClN2O4, produced by three different strains (SF1, SF2, and SF5), was subject of an attempted purification. However, it was demonstrated using confocal microscopy and LC/MS high resolution that this compound is produced only on solid culture. These three potential antimicrobial isolates showed high similarity with Streptomyces thinghirensis and Streptomyces lienomycini, in terms of morphological characteristics and 16S rRNA gene sequences (bootstrap 97 %). All these findings prove the high antimicrobial diversity of the studied soils. The potential of the selected and other relatively unexplored extreme environments constitute a source of interesting actinomycete strains producing several biologically active secondary metabolites.

BioMed Research International, 2015

Concern over the reports of antibiotic-resistant bacterial infections in hospitals and in the com... more Concern over the reports of antibiotic-resistant bacterial infections in hospitals and in the community has been publicized in the media, accompanied by comments on the risk that we may soon run out of antibiotics as a way to control infectious disease. Infections caused byEnterococcus faecium, Staphylococcus aureus, Klebsiellaspecies,Clostridium difficile, Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli, and otherEnterobacteriaceaespecies represent a major public health burden. Despite the pharmaceutical sector’s lack of interest in the topic in the last decade, microbial natural products continue to represent one of the most interesting sources for discovering and developing novel antibacterials. Research in microbial natural product screening and development is currently benefiting from progress that has been made in other related fields (microbial ecology, analytical chemistry, genomics, molecular biology, and synthetic biology). In this paper, we review how no...

International Journal of Molecular Sciences

Sleeping sickness or African trypanosomiasis is a serious health concern with an added socio-econ... more Sleeping sickness or African trypanosomiasis is a serious health concern with an added socio-economic impact in sub-Saharan Africa due to direct infection in both humans and their domestic livestock. There is no vaccine available against African trypanosomes and its treatment relies only on chemotherapy. Although the current drugs are effective, most of them are far from the modern concept of a drug in terms of toxicity, specificity and therapeutic regime. In a search for new molecules with trypanocidal activity, a high throughput screening of 2000 microbial extracts was performed. Fractionation of one of these extracts, belonging to a culture of the fungus Amesia sp., yielded a new member of the curvicollide family that has been designated as curvicollide D. The new compound showed an inhibitory concentration 50 (IC50) 16-fold lower in Trypanosoma brucei than in human cells. Moreover, it induced cell cycle arrest and disruption of the nucleolar structure. Finally, we showed that cu...

Antibiotics, 2020

An antifungal lipodepsipeptide was obtained from cultures of the fungus Foliophoma fallens CF-236... more An antifungal lipodepsipeptide was obtained from cultures of the fungus Foliophoma fallens CF-236885. Its structure, elucidated by HRMS and NMR spectroscopy, contained Gly, Thr, Asn, β-Ala, Orn, Ala, two Ser residues, and 3-hydroxy-4-methylhexadecanoic acid. The absolute configuration of its amino acid residues was determined using Marfey’s analysis and J-based configuration analysis helped to establish the relative configuration of the 3-hydroxy-4-methylhexadecanoic acid moiety. A literature search retrieved a patent describing antibiotic TKR2999 (1), whose non-disclosed structure was confirmed to be identical to that found for our compound, according to its physicochemical properties and NMR spectra. Compound 1 displayed potent antifungal activity against Aspergillus fumigatus and a panel of Candida strains.

Marine Drugs, 2019

As part of our continuing efforts to discover new bioactive compounds from microbial sources, a r... more As part of our continuing efforts to discover new bioactive compounds from microbial sources, a reinvestigation of extracts of scaled-up cultures of the marine-derived Streptomyces sp. strain CA-271078 resulted in the isolation and structural elucidation of four new napyradiomycins (1–3, 5). The known napyradiomycin SC (4), whose structural details had not been previously described in detail, and another ten related known compounds (6–15). The structures of the new napyradiomycins were characterized by HRMS and 1D- and 2D-NMR spectroscopies and their relative configurations were established through a combination of molecular modelling with nOe and coupling constants NMR analysis. The absolute configuration of each compound is also proposed based on biosynthetic arguments and the comparison of specific rotation data with those of related compounds. Among the new compounds, 1 was determined to be the first non-halogenated member of napyradiomycin A series containing a functionalized p...

Metabolites, 2019

Fungi are one of the most prolific sources of microbial secondary metabolites. The production of ... more Fungi are one of the most prolific sources of microbial secondary metabolites. The production of new metabolites can be achieved using multiple fermentation conditions and by adding small-molecule effectors, including epigenetic modifiers. In the framework of our Natural Product screening programme targeting the discovery of new antimicrobial compounds, we applied multiple fermentation conditions and adsorptive polymeric resins on a large collection of fungal endophytes, to increase and stimulate their fungal secondary metabolite production. During this work the endophytic fungus Dimorphosporicola tragani CF-090383 showed antimicrobial activity only when grown in presence of adsorptive polymeric resins. In addition, seven epigenetic modifiers were added to fermentations of this endophytic fungus, in an attempt to activate its cryptic pathways as well as to analyse the metabolites produced under these conditions. D. tragani was seen to produce three different mycotoxin dendrodolides ...

Antibiotics, 2018

The current spread of multi-drug resistance in a number of key pathogens and the lack of therapeu... more The current spread of multi-drug resistance in a number of key pathogens and the lack of therapeutic solutions in development to address most of the emerging infections in the clinic that are difficult to treat have become major concerns. Microbial natural products represent one of the most important sources for the discovery of potential new antibiotics and actinomycetes have been one of the most relevant groups that are prolific producers of these bioactive compounds. Advances in genome sequencing and bioinformatic tools have collected a wealth of knowledge on the biosynthesis of these molecules. This has revealed the broad untapped biosynthetic diversity of actinomycetes, with large genomes and the capacity to produce more molecules than previously estimated, opening new opportunities to identify the novel classes of compounds that are awaiting to be discovered. Comparative genomics, metabolomics and proteomics and the development of new analysis and genetic engineering tools pro...

Biology and Biotechnology of Actinobacteria, 2017

The use of general descriptive names, registered names, trademarks, service marks, etc. in this p... more The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Scientific reports, Jan 27, 2018

Native plant communities from arid areas present distinctive characteristics to survive in extrem... more Native plant communities from arid areas present distinctive characteristics to survive in extreme conditions. The large number of poorly studied endemic plants represents a unique potential source for the discovery of novel fungal symbionts as well as host-specific endophytes not yet described. The addition of adsorptive polymeric resins in fungal fermentations has been seen to promote the production of new secondary metabolites and is a tool used consistently to generate new compounds with potential biological activities. A total of 349 fungal strains isolated from 63 selected plant species from arid ecosystems located in the southeast of the Iberian Peninsula, were characterized morphologically as well as based on their ITS/28S ribosomal gene sequences. The fungal community isolated was distributed among 19 orders including Basidiomycetes and Ascomycetes, being Pleosporales the most abundant order. In total, 107 different genera were identified being Neocamarosporium the genus mo...

Marine drugs, Jan 16, 2018

Phocoenamicins B and C (and), together with the known spirotetronate phocoenamicin (), were isola... more Phocoenamicins B and C (and), together with the known spirotetronate phocoenamicin (), were isolated from cultures ofsp. The acetone extract from a culture of this strain, isolated from marine sediments collected in the Canary Islands, displayed activity against methicillin-resistant(MRSA),H37Ra and. Bioassay-guided fractionation of this extract using SP207ss column chromatography and preparative reversed-phased HPLC led to the isolation of the new compoundsandbelonging to the spirotetronate class of polyketides. Their structures were determined using a combination of HRMS, 1D and 2D NMR experiments and comparison with the spectra reported for phocoenamicin. Antibacterial activity tests of the pure compounds against these pathogens revealed minimal inhibitory concentration (MIC) values ranging from 4 to 64 µg/mL for MRSA, and 16 to 32 µg/mL forH37Ra, with no significant activity found againstand vancomycin-resistant(VRE) at concentrations below 128 µg/mL, and weak activity detected ...

Natural Product Reports, 2017

An update on last ten years of actinomycetes antibiotic discovery, including recent key molecules... more An update on last ten years of actinomycetes antibiotic discovery, including recent key molecules in clinical development and overlooked compounds discovered using novel strategies.

Frontiers in pharmacology, 2017

Nitric-oxide synthase, the enzyme responsible for mammalian nitric oxide generation, and cytochro... more Nitric-oxide synthase, the enzyme responsible for mammalian nitric oxide generation, and cytochrome P450, the major enzymes involved in drug metabolism, share striking similarities. Therefore, it makes sense that cytochrome P450 drug mediated biotransformations might play an important role in the pharmacological modulation of nitric oxide synthase. In this work, we have undertaken an integrated in vitro assessment of the hepatic metabolism and nitric oxide modulation of previously described dual inhibitors (imidazoles and macrolides) of these enzymes in order assess the implication of CYP450 activities over production of nitric oxide. In vitro systems based in human liver microsomes and activated mouse macrophages were developed for these purposes. Additionally in vitro production the hepatic metabolites of dual inhibitor, roxithromycin, was investigated achieving the identification and isolation of main hepatic biotransformation products. Our results suggested that for some macroli...

Frontiers in microbiology, 2017

In this report, we describe a High-Throughput Screening (HTS) to identify compounds that inhibit ... more In this report, we describe a High-Throughput Screening (HTS) to identify compounds that inhibit biofilm formation or cause the disintegration of an already formed biofilm using the Salmonella Enteritidis 3934 strain. Initially, we developed a new methodology for growing Salmonella biofilms suitable for HTS platforms. The biomass associated with biofilm at the solid-liquid interface was quantified by staining both with resazurin and crystal violet, to detect living cells and total biofilm mass, respectively. For a pilot project, a subset of 1120 extracts from the Fundación MEDINA's collection was examined to identify molecules with antibiofilm activity. This is the first validated HTS assay of microbial natural product extracts which allows for the detection of four types of activities which are not mutually exclusive: inhibition of biofilm formation, detachment of the preformed biofilm and antimicrobial activity against planktonic cells or biofilm embedded cells. Currently, sev...

Frontiers in microbiology, 2017

Ramoplanin is a glycolipodepsipeptide antibiotic obtained from fermentation of Actinoplanes sp. A... more Ramoplanin is a glycolipodepsipeptide antibiotic obtained from fermentation of Actinoplanes sp. ATCC 33076 that exhibits activity against clinically important multi-drug-resistant, Gram-positive pathogens including vancomycin-resistant Enterococcus (VRE), methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-intermediate resistant Clostridium difficile. It disrupts bacterial cell wall through a unique mechanism of action by sequestering the peptidoglycan intermediate Lipid II and therefore does not show cross-resistance with other antibiotics. However, while demonstrating excellent antimicrobial activity in systemic use in animal models of infection, ramoplanin presents low local tolerability when injected intravenously. As a consequence of this limitation, new derivatives are desirable to overcome this issue. During a natural product screening program developed to discover compounds that disrupt bacterial cell wall synthesis by inhibiting peptidoglycan transglycosylati...

Journal of Natural Products, 2017

S1 Overlapped HSQC spectra of hormonemate B (2) and erythritol, showing the 'alditol' region. Blu... more S1 Overlapped HSQC spectra of hormonemate B (2) and erythritol, showing the 'alditol' region. Blue and red signals correspond to hormonemate B whereas green and pink are those of a standard of erythritol. S2 Overlapped HSQC spectra of hormonemate (5) and D-mannitol, showing the 'alditol' region. Blue and red signals correspond to hormonemate whereas green and pink are those of a standard of D-mannitol. S3 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate A (1). S4 Zoom shot of the 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate A (1). S5 13 C-NMR (125 MHz, methanol-d4) spectrum of hormonemate A (1). S6 HSQC (methanol-d4) spectrum of hormonemate A (1). S7 HMBC (methanol-d4) spectrum of hormonemate A (1). S8 COSY (methanol-d4) spectrum of hormonemate A (1). S9 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate B (2). S10 Zoom shot of the 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate B (2). S11 13 C-NMR (125 MHz, methanol-d4) spectrum of hormonemate B (2). S12 HSQC (methanol-d4) spectrum of hormonemate B (2). S13 HMBC (methanol-d4) spectrum of hormonemate B (2). S14 COSY (methanol-d4) spectrum of hormonemate B (2). S15 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate C (3). S16 Zoom shot of the 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate C (3). S17 13 C-NMR (125 MHz, methanol-d4) spectrum of hormonemate C (3). S18 HSQC (methanol-d4) spectrum of hormonemate C (3). S19 HMBC (methanol-d4) spectrum of hormonemate C (3). S20 COSY (methanol-d4) spectrum of hormonemate C (3). S21 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate D (4). S22 Zoom shot of the 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate D (4). S23 13 C-NMR (125 MHz, methanol-d4) spectrum of hormonemate D (4). S24 HSQC (methanol-d4) spectrum of hormonemate D (4). S25 HMBC (methanol-d4) spectrum of hormonemate D (4). S26 COSY (methanol-d4) spectrum of hormonemate D (4). S27 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate (5). S28 Zoom shot of the 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate (5). S29 13 C-NMR (125 MHz, methanol-d4) spectrum of hormonemate (5). S30 HSQC (methanol-d4) spectrum of hormonemate (5). S31 HMBC (methanol-d4) spectrum of hormonemate (5). S32 COSY (methanol-d4) spectrum of hormonemate (5). S33 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate E (6). S34 Zoom shot of the 1 H-NMR (500 MHz, methanol-d4) spectrum of hormonemate E (6). S35 13 C-NMR (125 MHz, methanol-d4) spectrum of hormonemate E (6). S36 HSQC (methanol-d4) spectrum of hormonemate E (6). S37 HMBC (methanol-d4) spectrum of hormonemate E (6). S38 COSY (methanol-d4) spectrum of hormonemate E (6).

Marine Drugs, 2016

A new napyradiomycin, MDN-0170 (1), was isolated from the culture broth of the marine-derived act... more A new napyradiomycin, MDN-0170 (1), was isolated from the culture broth of the marine-derived actinomycete strain CA-271078, together with three known related compounds identified as 4-dehydro-4a-dechloronapyradiomycin A1 (2), napyradiomycin A1 (3) and 3-chloro-6,8-dihydroxy-8-α-lapachone (4). The structure of the new compound was determined using a combination of spectroscopic techniques, including 1D and 2D NMR and electrospray-time of flight mass spectrometry (ESI-TOF MS). The relative configuration of compound 1, which contains two independent stereoclusters, has been established by molecular modelling in combination with nOe and coupling constant analyses. Biosynthetic arguments also allowed us to propose its absolute stereochemistry. The antimicrobial properties of the compounds isolated were evaluated against methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, Aspergillus fumigatus, and Candida albicans. The potent bioactivity previously reported for compounds 2 and 3 against methicillin-sensitive S. aureus has been extended to methicillin-resistant strains in this report.

Planta medica, Jan 5, 2016

During a high-throughput screening program focused on the discovery and characterization of new a... more During a high-throughput screening program focused on the discovery and characterization of new antifungal compounds, a total of 8320 extracts from Fundacion MEDINA's collection were screened against a panel of 6 fungal parasitic strains, namely Candida glabrata, Candida krusei, Candida parapsilosis, Candida tropicalis, Candida albicans, and Aspergillus fumigatus. A total of 127 extracts displayed antifungal properties and, after LC/MS dereplication, 10 were selected for further fractionation. Bioassay-guided fractionation from a 1-L fermentation of one of these extracts, belonging to the fungus Chaetopsina sp., led to the isolation of linoleyl sulphate (1), linolenyl sulphate (2), and oleyl sulphate (3) as the compounds responsible for the antifungal activity. These molecules were previously described as synthetic products with the ability to produce the allosteric inhibition of soybean lipoxygenase and human lipoxygenase.

Current Microbiology, 2016

Fifty four isolates of actinomycetes were collected from four different rhizospheric soils: 18 st... more Fifty four isolates of actinomycetes were collected from four different rhizospheric soils: 18 strains from palm tree bark and soil, 12 strains from an olive field soil, 9 strains from a coastal forest, and 15 strains from an agriculture soil situated in the Algerian-Tunisian border (Oum Tboul). Based on morphological and cultural characters, the isolates were classified as Streptomyces (42 strains), Micromonospora (4 strains), Pseudonocardia (1 strain), Actinomadura (1 strain), Nocardia (1 strain), and non-Streptomyces (5 strains). More than half of the isolates inhibited at least one tested pathogenic microorganisms in liquid culture. In addition, antimicrobial activities of some strains were tested on solid culture. Several bioactive compounds were identified by liquid chromatography joined with low-resolution mass spectroscopy (LC/MS) and analysed by MEDINA's database and by the dictionary of natural products Chapman & Hall. An interesting chlorinated compound with the molecular formula C20H37ClN2O4, produced by three different strains (SF1, SF2, and SF5), was subject of an attempted purification. However, it was demonstrated using confocal microscopy and LC/MS high resolution that this compound is produced only on solid culture. These three potential antimicrobial isolates showed high similarity with Streptomyces thinghirensis and Streptomyces lienomycini, in terms of morphological characteristics and 16S rRNA gene sequences (bootstrap 97 %). All these findings prove the high antimicrobial diversity of the studied soils. The potential of the selected and other relatively unexplored extreme environments constitute a source of interesting actinomycete strains producing several biologically active secondary metabolites.