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1.
Artículo en Inglés | MEDLINE | ID: mdl-37527356

RESUMEN

ABSTRACT: Collecting and reporting accurate disaster mortality data are critical to informing disaster response and recovery efforts. The National Association of Medical Examiners convened an ad hoc committee to provide recommendations for the documentation and certification of disaster-related deaths. This article provides definitions for disasters and direct, indirect, and partially attributable disaster-related deaths; discusses jurisdiction for disaster-related deaths; offers recommendations for medical examiners/coroners (ME/Cs) for indicating the involvement of the disaster on the death certificate; discusses the role of the ME/C and non-ME/C in documenting and certifying disaster-related deaths; identifies existing systems for helping to identify the role of disaster on the death certificate; and describes disaster-related deaths that may require amendments of death certificates. The recommendations provided in this article seek to increase ME/C's understanding of disaster-related deaths and promote uniformity in how to document these deaths on the death certificate.

3.
Neuropathol Appl Neurobiol ; 48(1): e12746, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34164845

RESUMEN

AIMS: Hippocampal findings are implicated in the pathogenesis of sudden unexplained death in childhood (SUDC), although some studies have identified similar findings in sudden explained death in childhood (SEDC) cases. We blindly reviewed hippocampal histology in SUDC and SEDC controls. METHODS: Hippocampal haematoxylin and eosin (H&E) slides (n = 67; 36 SUDC, 31 controls) from clinical and forensic collaborators were evaluated by nine blinded reviewers: three board-certified forensic pathologists, three neuropathologists and three dual-certified neuropathologists/forensic pathologists. RESULTS: Among nine reviewers, about 50% of hippocampal sections were rated as abnormal (52.5% SUDC, 53.0% controls), with no difference by cause of death (COD) (p = 0.16) or febrile seizure history (p = 0.90). There was little agreement among nine reviewers on whether a slide was within normal range (Fleiss' κ = 0.014, p = 0.47). Within reviewer groups, there were no findings more frequent in SUDC compared with controls, with variability in pyramidal neuron and dentate gyrus findings. Across reviewer groups, there was concordance for bilamination and granule cell loss. Neither SUDC (51.2%) nor control (55.9%) slides were considered contributory to determining COD (p = 0.41). CONCLUSIONS: The lack of an association of hippocampal findings in SUDC and controls, as well as inconsistency of observations by multiple blinded reviewers, indicates discrepancy with previous studies and an inability to reliably identify hippocampal maldevelopment associated with sudden death (HMASD). These findings underscore a need for larger studies to standardise evaluation of hippocampal findings, identifying the range of normal variation and changes unrelated to SUDC or febrile seizures. Molecular studies may help identify novel immunohistological markers that inform on COD.


Asunto(s)
Neuropatología , Convulsiones Febriles , Encéfalo/patología , Niño , Muerte Súbita/patología , Hipocampo/patología , Humanos , Convulsiones Febriles/complicaciones , Convulsiones Febriles/patología
4.
Nat Biotechnol ; 39(2): 169-173, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33169034

RESUMEN

We engineered a machine learning approach, MSHub, to enable auto-deconvolution of gas chromatography-mass spectrometry (GC-MS) data. We then designed workflows to enable the community to store, process, share, annotate, compare and perform molecular networking of GC-MS data within the Global Natural Product Social (GNPS) Molecular Networking analysis platform. MSHub/GNPS performs auto-deconvolution of compound fragmentation patterns via unsupervised non-negative matrix factorization and quantifies the reproducibility of fragmentation patterns across samples.


Asunto(s)
Algoritmos , Cromatografía de Gases y Espectrometría de Masas , Metabolómica , Animales , Anuros , Humanos
5.
JAMA Netw Open ; 3(10): e2023262, 2020 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-33125496

RESUMEN

Importance: The true incidence of sudden unexplained death in childhood (SUDC), already the fifth leading category of death among toddlers by current US Centers for Disease Control and Prevention estimates, is potentially veiled by the varied certification processes by medicolegal investigative offices across the United States. Objective: To evaluate the frequency of SUDC incidence, understand its epidemiology, and assess the consistency of death certification among medical examiner and coroner offices in the US death investigation system. Design, Setting, and Participants: In this case series, 2 of 13 forensic pathologists (FPs) conducted masked reviews of 100 cases enrolled in the SUDC Registry and Research Collaborative (SUDCRRC). Children who died aged 11 months to 18 years from 36 US states, Canada, and the United Kingdom had been posthumously enrolled in the SUDCRRC by family members from 2014 to 2017. Comprehensive data from medicolegal investigative offices, clinical offices, and family members were reviewed. Data analysis was conducted from December 2014 to June 2020. Main Outcomes and Measures: Certified cause of death (COD) characterized as explained (accidental or natural) or unexplained, as determined by SUDCRRC masked review process. Results: In this study of 100 cases of SUDC (mean [SD] age, 32.1 [31.8] months; 58 [58.0%] boys; 82 [82.0%] White children; 92 [92.0%] from the United States), the original pathologist certified 43 cases (43.0%) as explained COD and 57 (57.0%) as unexplained COD. The SUDCRRC review process led to the following certifications: 16 (16.0%) were explained, 7 (7.0%) were undetermined because of insufficient data, and 77 (77.0%) were unexplained. Experts disagreed with the original COD in 40 cases (40.0%). These data suggest that SUDC incidence is higher than the current Centers for Disease Control and Prevention estimate (ie, 392 deaths in 2018). Conclusions and Relevance: To our knowledge, this is the first comprehensive masked forensic pathology review process of sudden unexpected pediatric deaths, and it suggests that SUDC may often go unrecognized in US death investigations. Some unexpected pediatric deaths may be erroneously attributed to a natural or accidental COD, negatively affecting surveillance, research, public health funding, and medical care of surviving family members. To further address the challenges of accurate and consistent death certification in SUDC, future studies are warranted.


Asunto(s)
Síndrome de Brugada/etiología , Causas de Muerte/tendencias , Certificado de Defunción , Síndrome de Brugada/epidemiología , Canadá/epidemiología , Preescolar , Testimonio de Experto , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Oportunidad Relativa , Factores de Riesgo , Estados Unidos/epidemiología
6.
J Nat Prod ; 83(6): 1810-1816, 2020 06 26.
Artículo en Inglés | MEDLINE | ID: mdl-32510948

RESUMEN

Pierce's disease of grapevine and citrus huanglongbing are caused by the bacterial pathogens Xylella fastidiosa and Candidatus Liberibacter asiaticus (CLas), respectively. Both pathogens reside within the plant vascular system, occluding water and nutrient transport, leading to a decrease in productivity and fruit marketability and ultimately death of their hosts. Field observations of apparently healthy plants in disease-affected vineyards and groves led to the hypothesis that natural products from endophytes may inhibit these bacterial pathogens. Previously, we showed that the natural product radicinin from Cochliobolus sp. inhibits X. fastidiosa. Herein we describe a chemical synthesis of deoxyradicinin and establish it as an inhibitor of both X. fastidiosa and Liberibacter crescens, a culturable surrogate for CLas. The key to this three-step route is a zinc-mediated enolate C-acylation, which allows for direct introduction of the propenyl side chain without extraneous redox manipulations.


Asunto(s)
Antibacterianos/síntesis química , Antibacterianos/farmacología , Liberibacter/efectos de los fármacos , Pironas/síntesis química , Pironas/farmacología , Xylella/efectos de los fármacos , Acetilación , Citrus , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Oxidación-Reducción , Enfermedades de las Plantas/microbiología , Pironas/química , Solubilidad , Vitis
7.
Appl Environ Microbiol ; 86(8)2020 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-32086307

RESUMEN

Huanglongbing (HLB) is a destructive citrus disease that is lethal to all commercial citrus plants, making it the most serious citrus disease and one of the most serious plant diseases. Because of the severity of HLB and the paucity of effective control measures, we structured this study to encompass the entirety of the citrus microbiome and the chemistries associated with that microbial community. We describe the spatial niche diversity of bacteria and fungi associated with citrus roots, stems, and leaves using traditional microbial culturing integrated with culture-independent methods. Using the culturable sector of the citrus microbiome, we created a microbial repository using a high-throughput bulk culturing and microbial identification pipeline. We integrated an in vitro agar diffusion inhibition bioassay into our culturing pipeline that queried the repository for antimicrobial activity against Liberibacter crescens, a culturable surrogate for the nonculturable "Candidatus Liberibacter asiaticus" bacterium associated with HLB. We identified microbes with robust inhibitory activity against L. crescens that include the fungi Cladosporium cladosporioides and Epicoccum nigrum and bacterial species of Pantoea, Bacillus, and Curtobacterium Purified bioactive natural products with anti-"Ca. Liberibacter asiaticus" activity were identified from the fungus C. cladosporioides Bioassay-guided fractionation of an organic extract of C. cladosporioides yielded the natural products cladosporols A, C, and D as the active agents against L. crescens This work serves as a foundation for unraveling the complex chemistries associated with the citrus microbiome to begin to understand the functional roles of members of the microbiome, with the long-term goal of developing anti-"Ca Liberibacter asiaticus" bioinoculants that thrive in the citrus holosystem.IMPORTANCE Globally, citrus is threatened by huanglongbing (HLB), and the lack of effective control measures is a major concern of farmers, markets, and consumers. There is compelling evidence that plant health is a function of the activities of the plant's associated microbiome. Using Liberibacter crescens, a culturable surrogate for the unculturable HLB-associated bacterium "Candidatus Liberibacter asiaticus," we tested the hypothesis that members of the citrus microbiome produce potential anti-"Ca Liberibacter asiaticus" natural products with potential anti-"Ca Liberibacter asiaticus" activity. A subset of isolates obtained from the microbiome inhibited L. crescens growth in an agar diffusion inhibition assay. Further fractionation experiments linked the inhibitory activity of the fungus Cladosporium cladosporioides to the fungus-produced natural products cladosporols A, C, and D, demonstrating dose-dependent antagonism to L. crescens.


Asunto(s)
Citrus/microbiología , Microbiota , Enfermedades de las Plantas/microbiología , Rhizobiaceae/aislamiento & purificación , Rhizobiaceae/fisiología , Microbiología del Suelo , Fenómenos Fisiológicos Bacterianos , Hongos/fisiología
8.
J Nat Prod ; 83(3): 693-705, 2020 03 27.
Artículo en Inglés | MEDLINE | ID: mdl-31971803

RESUMEN

Sarcophyton glaucum is one of the most abundant and chemically studied soft corals with over 100 natural products reported in the literature, primarily cembrane diterpenoids. Yet, wide variation in the chemistry observed from S. glaucum over the past 50 years has led to its reputation as a capricious producer of bioactive metabolites. Recent molecular phylogenetic analysis revealed that S. glaucum is not a single species but a complex of at least seven genetically distinct species not distinguishable using traditional taxonomic criteria. We hypothesized that perceived intraspecific chemical variation observed in S. glaucum was actually due to differences between cryptic species (interspecific variation). To test this hypothesis, we collected Sarcophyton samples in Palau, performed molecular phylogenetic analysis, and prepared chemical profiles of sample extracts using gas chromatography-flame ionization detection. Both unsupervised (principal component analysis) and supervised (linear discriminant analysis) statistical analyses of these profiles revealed a strong relationship between cryptic species membership and chemical profiles. Liquid chromatography with tandem mass spectrometry-based analysis using feature-based molecular networking permitted identification of the chemical drivers of this difference between clades, including cembranoid diterpenes (2R,11R,12R)-isosarcophytoxide (5), (2S,11R,12R)-isosarcophytoxide (6), and isosarcophine (7). Our results suggest that early chemical studies of Sarcophyton may have unknowingly conflated different cryptic species of S. glaucum, leading to apparently idiosyncratic chemical variation.


Asunto(s)
Antozoos/química , Antozoos/clasificación , Diterpenos/química , Animales , Estructura Molecular , Palau , Filogenia , Metabolismo Secundario
9.
Mar Drugs ; 16(4)2018 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-29659509

RESUMEN

Antartin (1), a new zizaane-type sesquiterpene, was isolated from Streptomyces sp. SCO736. The chemical structure of 1 was assigned from the interpretation of 1D and 2D NMR in addition to mass spectrometric data. The relative stereochemistry of 1 was determined by analysis of NOE data, while the absolute stereochemistry was decided based on a comparison of experimental and calculated electronic circular dichroism (ECD) spectra. Antartin (1) showed cytotoxicity against A549, H1299, and U87 cancer cell lines by causing cell cycle arrest at the G1 phase.


Asunto(s)
Citotoxinas/química , Sesquiterpenos/química , Streptomyces/química , Células A549 , Regiones Antárticas , Línea Celular Tumoral , Dicroismo Circular , Citotoxinas/farmacología , Fase G1/efectos de los fármacos , Sedimentos Geológicos/microbiología , Humanos , Espectroscopía de Resonancia Magnética/métodos , Sesquiterpenos/farmacología
10.
Open Forum Infect Dis ; 4(1): ofw277, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28480269

RESUMEN

BACKGROUND: Globicatella sanguinis is an uncommon pathogen that may be misdiagnosed as viridans group streptococci. We review the literature of Globicatella and report 2 clinical cases in which catalase-negative Gram-positive cocci resembling viridans group streptococci with elevated minimum inhibitory concentrations (MICs) to ceftriaxone were inconsistently identified phenotypically, with further molecular characterization and ultimate identification of G sanguinis. METHODS: Two clinical strains (from 2 obese women; 1 with a prosthetic hip infection and the other with bacteremia) were analyzed with standard identification methods, followed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry, 16S recombinant ribonucleic acid (rRNA), and sodA polymerase chain reaction (PCR). The existing medical literature on Globicatella also was reviewed. RESULTS: Standard phenotypic methods failed to consistently identify the isolates. 16S PCR yielded sequences that confirmed Globicatella species. sodA sequencing provided species-level identification of G sanguinis. The review of literature reveals G sanguinis as an increasingly reported cause of infections of the urine, meninges, and blood. To our knowledge, this is the first reported case of an orthopedic infection caused by Globicatella sanguinis. A review of the 37 known cases of G sanguinis infection revealed that 83% of patients are female, and 89% are at the extremes of age (<5 or >65 years). CONCLUSIONS: Globicatella sanguinis, an uncommon pathogen with elevated minimum inhibitory concentrations to third-generation cephalosporins, is difficult to identify by phenotypic methods and typically causes infections in females at the extremes of age. It may colonize skin or mucosal surfaces. Advanced molecular techniques utilizing 16S rRNA with sodA PCR accurately identify G sanguinis.

11.
Bioorg Med Chem ; 23(21): 7007-14, 2015 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-26439661

RESUMEN

Nordihydroguaiaretic acid (NDGA) is a natural polyphenol with a broad spectrum of pharmacological properties. However, its usefulness is hindered by the lack of understanding of its pharmacological and toxicological pathways. Previously we showed that oxidative cyclisation of NDGA at physiological pH forms a dibenzocyclooctadiene that may have therapeutic benefits whilst oxidation to an ortho-quinone likely mediates toxicological properties. NDGA analogues with higher propensity to cyclise under physiologically relevant conditions might have pharmacological implications, which motivated this study. We synthesized a series of NDGA analogues which were designed to investigate the structural features which influence the intramolecular cyclisation process and help to understand the mechanism of NDGA's autoxidative conversion to a dibenzocyclooctadiene lignan. We determined the ability of the NDGA analogues investigated to form dibenzocyclooctadienes and evaluated the oxidative stability at pH 7.4 of the analogues and the stability of any dibenzocyclooctadienes formed from the NDGA analogues. We found among our group of analogues the catechols were less stable than phenols, a single catechol-substituted ring is insufficient to form a dibenzocyclooctadiene lignan, and only compounds possessing a di-catechol could form dibenzocyclooctadienes. This suggests that quinone formation may not be necessary for cyclisation to occur and the intramolecular cyclisation likely involves a radical-mediated rather than an electrophilic substitution process. We also determined that the catechol dibenzocyclooctadienes autoxidised at comparable rates to the parent catechol. This suggests that assigning in vitro biological activity to the NDGA dibenzocyclooctadiene is premature and requires additional study.


Asunto(s)
Antioxidantes/química , Masoprocol/análogos & derivados , Antioxidantes/síntesis química , Antioxidantes/metabolismo , Ciclización , Cinética , Masoprocol/síntesis química , Masoprocol/metabolismo , Oxidación-Reducción , Quinonas/química
12.
Phytochemistry ; 116: 130-137, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25892412

RESUMEN

The fastidious phytopathogenic bacterium, Xylella fastidiosa, poses a substantial threat to many economically important crops, causing devastating diseases including Pierce's Disease of grapevine. Grapevines (Vitis vinifera L.) planted in an area under Pierce's Disease pressure often display differences in disease severity and symptom expression, with apparently healthy vines growing alongside the dying ones, despite the fact that all the vines are genetic clones of one another. Under the hypothesis that endophytic microbes might be responsible for this non-genetic resistance to X. fastidiosa, endophytic fungi were isolated from vineyard cvs. 'Chardonnay' and 'Cabernet Sauvignon' grown under high Pierce's Disease pressure. A Cochliobolus sp. isolated from a Cabernet Sauvignon grapevine inhibited the growth of X. fastidiosa in vitro. Bioassay-guided isolation of an organic extract of Cochliobolus sp. yielded the natural product radicinin as the major active compound. Radicinin also inhibited proteases isolated from the culture supernatant of X. fastidiosa. In order to assess structure-activity relationships, three semi-synthetic derivatives of radicinin were prepared and tested for activity against X. fastidiosa in vitro. Assay results of these derivatives are consistent with enzyme inactivation by conjugate addition to carbon-10 of radicinin, as proposed previously.


Asunto(s)
Ascomicetos/química , Pironas/farmacología , Vitis/microbiología , Xylella/efectos de los fármacos , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Enfermedades de las Plantas/microbiología , Pironas/química , Pironas/aislamiento & purificación , Relación Estructura-Actividad
13.
Food Sci Nutr ; 2(4): 351-60, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25473492

RESUMEN

Sweet potato proteins have been shown to possess antioxidant and antidiabetic properties in vivo. The ability of a protein to exhibit systemic effects is somewhat unusual as proteins are typically susceptible to digestive enzymes. This study was undertaken to better understand how digestive enzymes affect sweet potato proteins. Two fractions of industrially processed sweet potato peel, containing 6.8% and 8.5% protein and 80.5% and 83.3% carbohydrate, were used as a source of protein. Sweet potato proteins were incubated with pepsin, trypsin, and chymotrypsin and protein breakdown was visualized with SDS-PAGE. After pepsin digestion, samples were assayed for amylase inhibitory activity. Sporamin, the major storage protein in sweet potatoes, which functions as a trypsin inhibitor as well, exhibited resistance to pepsin, trypsin, and chymotrypsin. Sporamin from blanched peel of orange sweet potatoes was less resistant to pepsin digestion than sporamin from outer peel and from extract of the white-skinned Caiapo sweet potato. Trypsin inhibitory activity remained after simulated gastric digestion, with the Caiapo potato protein and peel samples exhibiting higher inhibitory activity compared to the blanched peel sample. Amylase and chymotrypsin inhibitory activity was not present in any of the samples after digestion.

14.
J Food Sci ; 77(11): E307-12, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23163903

RESUMEN

UNLABELLED: Proteins isolated from sweet potatoes (Ipomoea batatas) have been shown to possess antidiabetic, antioxidant, and antiproliferative properties. The objective of this study was to chemically optimize a process for extracting proteins from sweet potato peel. The extraction procedure involved mixing peel with saline solvent to dissolve proteins and then precipitating with CaCl(2). Quadratic and segmented models were used to determine the optimum NaCl concentration and peel to solvent ratio to maximize protein solubility while minimizing solvent usage. A segmented model was also used to optimize the concentration of CaCl(2) used for precipitation. The highest yield was obtained by mixing blanched peelings with 59.7 mL of 0.025 mM NaCl per g peel and then precipitating with 6.8 mM CaCl(2). The results of this study show that potentially valuable proteins can be extracted from peel generated during processing of sweet potatoes and industrial costs can be minimized by using these optimum conditions. PRACTICAL APPLICATION: Potentially valuable proteins can be extracted from sweet potato peel, a waste product of sweet potato processing.


Asunto(s)
Manipulación de Alimentos/métodos , Ipomoea batatas/química , Proteínas de Plantas/aislamiento & purificación , Electroforesis en Gel de Poliacrilamida , Modelos Lineales
15.
Fetal Pediatr Pathol ; 31(5): 319-23, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22432966

RESUMEN

Hypertensive disease (HD) during pregnancy includes chronic hypertension (HTN), gestational hypertension (GH), and preeclampsia/eclampsia (PEC). Differences between types of HD have not been well studied. Clinicopathologic features were compared between the HD groups and controls. HD was associated with lower Apgar scores, intrauterine growth restriction, IUGR, and delivery at an earlier gestational age (GA). IUGR was less common in the GH group, gestational age was lowest in the PEC. As expected, HD is associated with placental lesions of malperfusion, younger GA, and increased incidence of IUGR and controls showed less chronic and more "acute" lesions (ACA, MEC). Finally, comparisons of the HD groups showed differences only in GA and IUGR in the GH group as compared to the HTN and PEC groups. This suggests that GH may be associated with less severe clinical disease while showing similar pathologic features.


Asunto(s)
Eclampsia/patología , Hipertensión/patología , Enfermedades Placentarias/patología , Placenta/patología , Preeclampsia/patología , Complicaciones Cardiovasculares del Embarazo/patología , Adulto , Puntaje de Apgar , Enfermedad Crónica , Comorbilidad , Eclampsia/epidemiología , Femenino , Retardo del Crecimiento Fetal/epidemiología , Retardo del Crecimiento Fetal/patología , Edad Gestacional , Humanos , Hipertensión/epidemiología , Recién Nacido , Ciudad de Nueva York/epidemiología , Trabajo de Parto Prematuro/epidemiología , Enfermedades Placentarias/epidemiología , Preeclampsia/epidemiología , Embarazo , Complicaciones Cardiovasculares del Embarazo/epidemiología , Nacimiento Prematuro/epidemiología
16.
Bioorg Med Chem ; 19(22): 6557-62, 2011 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-21745747

RESUMEN

Three new depsipeptides, fijimycins A-C (1-3), together with the known etamycin A (4), were isolated and identified from the fermentation broth of strain CNS-575, a Streptomyces sp. cultured from a marine sediment sample collected off Nasese, Fiji. The planar structures of the new fijimycins were assigned by combined interpretation of NMR and MS/MS spectroscopic data. These assignments were complicated by the fact that 1-3 occurred as complex amide conformational mixtures. The absolute configurations of the component amino acids were established using the Marfey's method. Fijimycins A-C, and etamycin A, were shown to possess significant in vitro antibacterial activity against three methicillin-resistant Staphylococcus aureus (MRSA) strains with MIC(100) values between 4 and 16 µg mL(-1).


Asunto(s)
Antibacterianos/aislamiento & purificación , Antibacterianos/metabolismo , Depsipéptidos/biosíntesis , Depsipéptidos/aislamiento & purificación , Streptomyces/química , Streptomyces/metabolismo , Antibacterianos/química , Antibacterianos/farmacología , Depsipéptidos/química , Depsipéptidos/farmacología , Fermentación , Fiji , Macrólidos/química , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Resonancia Magnética Nuclear Biomolecular , Espectrometría de Masas en Tándem
17.
Appl Environ Microbiol ; 77(11): 3617-25, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21498757

RESUMEN

Bacteria of the genus Frankia are mycelium-forming actinomycetes that are found as nitrogen-fixing facultative symbionts of actinorhizal plants. Although soil-dwelling actinomycetes are well-known producers of bioactive compounds, the genus Frankia has largely gone uninvestigated for this potential. Bioinformatic analysis of the genome sequences of Frankia strains ACN14a, CcI3, and EAN1pec revealed an unexpected number of secondary metabolic biosynthesis gene clusters. Our analysis led to the identification of at least 65 biosynthetic gene clusters, the vast majority of which appear to be unique and for which products have not been observed or characterized. More than 25 secondary metabolite structures or structure fragments were predicted, and these are expected to include cyclic peptides, siderophores, pigments, signaling molecules, and specialized lipids. Outside the hopanoid gene locus, no cluster could be convincingly demonstrated to be responsible for the few secondary metabolites previously isolated from other Frankia strains. Few clusters were shared among the three species, demonstrating species-specific biosynthetic diversity. Proteomic analysis of Frankia sp. strains CcI3 and EAN1pec showed that significant and diverse secondary metabolic activity was expressed in laboratory cultures. In addition, several prominent signals in the mass range of peptide natural products were observed in Frankia sp. CcI3 by intact-cell matrix-assisted laser desorption-ionization mass spectrometry (MALDI-MS). This work supports the value of bioinformatic investigation in natural products biosynthesis using genomic information and presents a clear roadmap for natural products discovery in the Frankia genus.


Asunto(s)
Productos Biológicos/biosíntesis , Vías Biosintéticas/genética , Frankia/genética , Frankia/metabolismo , Genómica , Proteómica , Familia de Multigenes
18.
Anal Chem ; 83(3): 1048-52, 2011 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-21192729

RESUMEN

Inhibitors of quinone reductase-2 (NQO2; QR-2) can have antimalarial activity and antitumor activities or can function as chemoprevention agents by preventing the metabolic activation of toxic quinones such as menadione. To expedite the search for new natural product inhibitors of QR-2, we developed a screening assay based on ultrafiltration liquid chromatography-mass spectrometry that is compatible with complex samples such as bacterial or botanical extracts. Human QR-2 was prepared recombinantly, and the known QR-2 inhibitor, resveratrol, was used as a positive control and as a competitive ligand to eliminate false positives. Ultrafiltration LC-MS screening of extracts of marine sediment bacteria resulted in the discovery of tetrangulol methyl ether as an inhibitor of QR-2. When applied to the screening of hop extracts from the botanical, Humulus lupulus L., xanthohumol and xanthohumol D were identified as ligands of QR-2. Inhibition of QR-2 by these ligands was confirmed using a functional enzyme assay. Furthermore, binding of xanthohumol and xanthohumol D to the active site of QR-2 was confirmed using X-ray crystallography. Ultrafiltration LC-MS was shown to be a useful assay for the discovery of inhibitors of QR-2 in complex matrixes such as extracts of bacteria and botanicals.


Asunto(s)
Productos Biológicos/análisis , Cromatografía Liquida/métodos , Inhibidores Enzimáticos/análisis , Flavonoides/análisis , Humulus/química , Espectrometría de Masas/métodos , NAD(P)H Deshidrogenasa (Quinona)/antagonistas & inhibidores , Productos Biológicos/farmacología , Cristalografía por Rayos X , Evaluación Preclínica de Medicamentos , Inhibidores Enzimáticos/farmacología , Filtración , Flavonoides/farmacología , Humanos , Modelos Moleculares , Estructura Molecular , Propiofenonas/análisis , Propiofenonas/farmacología
19.
J Antibiot (Tokyo) ; 63(5): 219-24, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-20339399

RESUMEN

The alarming rise of hospital- and community-associated methicillin-resistant Staphylococcus aureus (HA- and CA-MRSA) infections has prompted a desperate search for novel antibiotics. We discovered the streptogramin etamycin produced by an actinomycete species isolated from the coast of Fiji, the first time this antibiotic has been identified from a marine microbe. Etamycin was extracted and purified from this strain (CNS-575) and identified as a three-rotamer species by 2D NMR spectroscopy. Etamycin demonstrated potent activity against HA- and CA-MRSA in microbroth dilution assays, with minimum inhibitory concentrations (MIC) as low as 1-2 mg l(-1) against HA- and CA-MRSA strains. Furthermore, etamycin was also active against other Gram-positive and several Gram-negative pathogens and was found to be non-cytotoxic at concentrations more than 20-fold above MIC. Etamycin displayed favorable time-kill kinetics compared with the first-line MRSA antibiotic, vancomycin, and also conferred significant protection from mortality in a murine model of systemic lethal MRSA infection. These data emphasize the utility of the marine environment as a relatively untapped source of antibiotics against major drug-resistant human pathogens. These studies will also guide future isolation and preclinical development of depsipeptide anti-MRSA compounds from marine-derived actinomycetes.


Asunto(s)
Antibacterianos/farmacología , Macrólidos/farmacología , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Actinobacteria/metabolismo , Animales , Antibacterianos/química , Antibacterianos/aislamiento & purificación , Antibacterianos/uso terapéutico , Femenino , Macrólidos/química , Macrólidos/aislamiento & purificación , Macrólidos/uso terapéutico , Espectroscopía de Resonancia Magnética , Ratones , Pruebas de Sensibilidad Microbiana , Infecciones Estafilocócicas/tratamiento farmacológico
20.
Org Lett ; 11(23): 5422-4, 2009 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-19883103

RESUMEN

Chemical examination of the secondary metabolites of a marine Saccharomonospora sp., isolated from marine sediments collected at the mouth of the La Jolla Submarine Canyon, yielded the unprecedented alkaloid lodopyridone (1). The low proton-to-carbon ratio of 1 precluded structure elucidation by NMR spectroscopic methods, thus the structure was defined by X-ray crystallography. Lodopyridone is cytotoxic to HCT-116 human colon cancer cells with IC(50) = 3.6 microM.


Asunto(s)
Actinobacteria/química , Alcaloides/aislamiento & purificación , Antineoplásicos/aislamiento & purificación , Alcaloides/química , Alcaloides/farmacología , Antineoplásicos/química , Antineoplásicos/farmacología , Cristalografía por Rayos X , Ensayos de Selección de Medicamentos Antitumorales , Células HCT116 , Humanos , Biología Marina , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Conformación Molecular , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular
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