Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 55
Filter
1.
Sensors (Basel) ; 24(5)2024 Feb 28.
Article in English | MEDLINE | ID: mdl-38475075

ABSTRACT

In photovoltaic power plant inspections, techniques for module assessment play a crucial role as they enhance fault detection and module characterization. One valuable technique is luminescence. The present paper introduces a novel technique termed passive luminescence. It enhances both electroluminescence and photoluminescence imaging acquisition in photovoltaic power plants under normal operation in high irradiance conditions. This technique is based on the development of an electronic board, which allows the polarity of the module to be changed, enabling the current generated by the photovoltaic string to be injected into the module and producing electroluminescence effects. Additionally, the board can bypass the module and set an open circuit, inducing photoluminescence emission using sunlight as an excitation source. The proper coordination of the board and an InGaAs camera with a bandpass filter has allowed for the integration of a lock-in technique, which has produced electroluminescence and photoluminescence pictures that can be used for fault detection.

2.
IEEE Rev Biomed Eng ; 16: 278-291, 2023.
Article in English | MEDLINE | ID: mdl-33961563

ABSTRACT

Medical and rehabilitation exoskeletons are being increasingly considered by therapists when choosing a treatment for individuals affected by lower limb impairments. Although all such exoskeletons seem to provide similar features and performance, there are, in practice, significant differences among them in terms of maximum walking speed, maximum torque, weight, autonomy, interaction with the user, or even the way to use it. In this review, the state of the art of the main commercial exoskeletons is described, while analyzing their properties, advantages, and disadvantages. Three groups are considered: complete exoskeletons, partial exoskeletons and open lines of research. A comparative analysis between them is performed while considering the main scientific and technical aspects to be improved. In conclusion to this analysis, the balance between feasibility and innovation in exoskeletons development is a design challenge. Commercial exoskeletons must fulfil standards whilst ensuring their safety and robustness. However, achieving a new generation of exoskeletons means a need to implement new hardware paradigms, and to enhance control strategies focused on assist-as-needed scheme. Finally, some aspects to improve current designs of the exoskeleton are presented.


Subject(s)
Exoskeleton Device , Humans , Lower Extremity
3.
Disabil Rehabil Assist Technol ; 18(4): 392-406, 2023 05.
Article in English | MEDLINE | ID: mdl-33332159

ABSTRACT

PURPOSE: To analyse the versatility and adaptability of commercially available exoskeletons for mobility assistance and their adaptation to diverse pathologies through a review of clinical trials in robotic lower limb training. DATA SOURCES: A computer-aided search in bibliographic databases (PubMed and Web of Science) of clinical trials published up to September 2020 was done. METHODS: To be selected for detailed review, clinical trials had to meet the following criteria: (1) a protocol was designed and approved, (2) participants were people with pathologies, and (3) the trials were not a single case study. Clinical trial data were collected, extracted, and analysed, considering: objectives, trial participants, number of sessions, pathologies involved, and conclusions. RESULTS: The search resulted in 312 potentially relevant studies of seven commercial exoskeletons, of which 135 passed the preliminary screening; and 69 studies were finally selected. Of the 69 clinical trials included in the review about 50% involved Spinal Cord Injury participants, while roughly 25% focussed on stroke and two trials corresponded to patients with both disorders. The rest were composed of neurological diseases and trauma disorders. CONCLUSIONS: The use of a single wearable robot for different medical conditions in various diseases is a challenge. Based on this comparative, the properties of the exoskeletons that improve the working ability with different pathologies and patient conditions have been evaluated. Suggestions were made for developing a new lower-limb exoskeleton based on various modules with a distributed control system to improve versatility in wearable technology for different gait pattern progression.Implications for rehabilitationWearable robotic exoskeletons for gait assistance have been analysed from the perspective of adaptation to different diseases.This paper emphasizes the importance of personalized therapies and adaptive assistive technology.Suggestions were made for a new modular exoskeleton capable of addressing the issue of low versatility characterizing currently wearable assistive technology.


Subject(s)
Exoskeleton Device , Robotics , Spinal Cord Injuries , Humans , Spinal Cord Injuries/rehabilitation , Lower Extremity , Gait
4.
Sensors (Basel) ; 22(23)2022 Nov 26.
Article in English | MEDLINE | ID: mdl-36501909

ABSTRACT

Within this paper, a PLC system that takes advantage of the loop resonance of an entire DC-PV string configured as a circular signal path is developed and implemented. Low cost and extremely simple transceivers intended to be installed within each PV module of a string have been designed and successfully tested. In addition, an anti-saturation coil has been conceived to avoid saturation of the core when the entire DC current of the string flows through it. Bi-directional half-duplex communication was successfully executed with up to a 1 MHz carrier frequency (150 kbps bitrate), using a simple ASK modulation scheme. The transmission and reception performance are presented, along with the overall system cost in comparison to the previous literature.


Subject(s)
Communication , Equipment Design
5.
J Pediatr Nurs ; 67: e71-e78, 2022.
Article in English | MEDLINE | ID: mdl-36192285

ABSTRACT

PURPOSE: Spinal Muscular Atrophy (SMA) Type II is a neurodegenerative disease that leads to progressive muscle weakness. It prevents children from walking and affects their respiratory function and their activity tolerance, among other health problems. We aimed to assess the activity tolerance showed by a child with SMA using a pediatric gait exoskeleton at home when walking and performing activities. DESIGN AND METHODS: This study presents the case of a 6-year-old boy with SMA Type II and respiratory failure who used a pediatric gait exoskeleton at home for a period of two months. A nursing assessment was done before and during the use of the device to evaluate the child's activity tolerance during the sessions. Nursing interviews, performance, vital signs, fatigue, field notes, and functional scales were analyzed. RESULTS: The nursing assessment showed a good activity tolerance of the child. Performance using the device improved over time; vital signs did not vary significantly during the sessions; fatigue perception decreased over time; and the child reached a higher score on some functional outcomes. CONCLUSIONS: A first step has been taken to evaluate the impact of exoskeleton technology in children with SMA Type II from the nursing point of view, exposing the potential of this technology for the care of children with neuromuscular diseases, and the need for more research on the topic. PRACTICE IMPLICATIONS: The information in this study will be useful to nurses to know the effects of gait exoskeletons in pediatric care of children with neuromuscular diseases like SMA.


Subject(s)
Exoskeleton Device , Muscular Atrophy, Spinal , Neurodegenerative Diseases , Spinal Muscular Atrophies of Childhood , Male , Child , Humans , Muscular Atrophy, Spinal/diagnosis , Spinal Muscular Atrophies of Childhood/diagnosis , Fatigue
6.
Enferm Infecc Microbiol Clin (Engl Ed) ; 40(3): 125-130, 2022 Mar.
Article in English | MEDLINE | ID: mdl-35249672

ABSTRACT

BACKGROUND: Clostridioides difficile infection (CDI) is a disease that is potentially preventable by vaccination. A good knowledge of its epidemiology, which can change over time, is warranted for prevention purposes and to help decision-making on the use of vaccines in public health programs. The objective of the research was to determine the epidemiology of healthcare-associated CDI (HA-CDI) and community-associated CDI (CA-CDI) in hospitalized patients in Spain using point prevalence data. METHODS: Point prevalence survey data on infections of hospitalized patients for years 2012-2019 were analyzed. HA-CDI and CA-CDI prevalence rates were calculated. Both HA-CDI and CA-CDI, as well as age group prevalence rates, were examined for trends. Patient comorbidities were tested for association to CDI. RESULTS: The prevalence of CDI in Spanish hospitals has grown exponentially from 14.1% in 2012 to 35.9% in 2019 (cases/10.000 hospitalized patients). Almost two thirds of the cases are of nosocomial onset. This increase was observed for HA-CDI and CA-CDI at an annual rate of 1.11% (CI 95% 1.08-1.15) and 1.09% (CI 95% 1.04-1.13), respectively. Patients 50 years old or older represent 87% of the total number of cases. Patients suffering from neoplasm (OR 1.39), immunodeficiency (OR 3.26), neutropenia (OR 3.70), cirrhosis (OR 1.92) and chronic renal failure (OR 1.91) have a significant increased risk of developing CDI, after adjusting for age. CONCLUSION: In Spain, the prevalence rate of both HA-CDI and CA-CDI have been increasing. Burden of CDI as well as clinical and epidemiological characteristics of CDI patients will help to support public health decision-making.


Subject(s)
Clostridioides difficile , Clostridium Infections , Cross Infection , Clostridium Infections/drug therapy , Clostridium Infections/epidemiology , Cross Infection/drug therapy , Cross Infection/epidemiology , Hospitals , Humans , Middle Aged , Spain/epidemiology
7.
Enferm. infecc. microbiol. clín. (Ed. impr.) ; 40(3): 1-6, Marzo, 2022. tab, graf
Article in English | IBECS | ID: ibc-203468

ABSTRACT

BackgroundClostridioides difficile infection (CDI) is a disease that is potentially preventable by vaccination. A good knowledge of its epidemiology, which can change over time, is warranted for prevention purposes and to help decision-making on the use of vaccines in public health programs. The objective of the research was to determine the epidemiology of healthcare-associated CDI (HA-CDI) and community-associated CDI (CA-CDI) in hospitalized patients in Spain using point prevalence data.MethodsPoint prevalence survey data on infections of hospitalized patients for years 2012–2019 were analyzed. HA-CDI and CA-CDI prevalence rates were calculated. Both HA-CDI and CA-CDI, as well as age group prevalence rates, were examined for trends. Patient comorbidities were tested for association to CDI.ResultsThe prevalence of CDI in Spanish hospitals has grown exponentially from 14.1% in 2012 to 35.9% in 2019 (cases/10.000 hospitalized patients). Almost two thirds of the cases are of nosocomial onset. This increase was observed for HA-CDI and CA-CDI at an annual rate of 1.11% (CI 95% 1.08–1.15) and 1.09% (CI 95% 1.04–1.13), respectively. Patients 50 years old or older represent 87% of the total number of cases. Patients suffering from neoplasm (OR 1.39), immunodeficiency (OR 3.26), neutropenia (OR 3.70), cirrhosis (OR 1.92) and chronic renal failure (OR 1.91) have a significant increased risk of developing CDI, after adjusting for age.ConclusionIn Spain, the prevalence rate of both HA-CDI and CA-CDI have been increasing. Burden of CDI as well as clinical and epidemiological characteristics of CDI patients will help to support public health decision-making.


AntecedentesLa infección por Clostridioides difficile (ICD) es una enfermedad potencialmente prevenible mediante vacunación. Es necesario conocer adecuadamente su epidemiología para ayudar a la toma de decisiones sobre su prevención y el uso de vacunas en programas de salud pública. El objetivo de esta investigación es determinar la epidemiología de ICD relacionada con la asistencia sanitaria (IRAS-CD) e ICD asociada a la comunidad (IAC-CD) en pacientes hospitalizados en España.MétodosAnalizamos los datos de encuestas de prevalencia puntual en pacientes hospitalizados durante los años 2012-2019. Calculamos las tasas de prevalencia de IRAS-CD e IAC-CD, y por grupos de edad, examinando sus tendencias. Evaluamos la asociación de ciertas comorbilidades con la ICD.ResultadosLa prevalencia de ICD en hospitales españoles ha crecido exponencialmente desde el 14,1% en 2012 al 35,9% en 2019 (casos/10.000 pacientes hospitalizados). Casi 2/3 de los casos son de inicio nosocomial. Este aumento se ha observado en IRAS-CD (1,11%; IC 95%: 1,08-1,15) e IAC-CD (1,09%; IC 95%: 1,04-1,13). Los pacientes de 50 años o más representan el 87% del total de casos. Los pacientes con neoplasia (OR: 1,39), inmunodeficiencia (OR: 3,26), neutropenia (OR: 3,70), cirrosis (OR: 1,92) e insuficiencia renal crónica (OR: 1,91) tienen un riesgo significativamente mayor de desarrollar ICD tras ajustar por edad.ConclusiónEn España la tasa de prevalencia de IRAS-CD e IAC-CD ha ido en aumento. Conocer la carga de la ICD y las características clínicas y epidemiológicas de los pacientes con ICD ayudará a la toma de decisiones en salud pública.


Subject(s)
Humans , Health Sciences , Epidemiology , Clostridioides difficile , Gram-Positive Rods
8.
Planta Med ; 88(2): 144-151, 2022 Feb.
Article in English | MEDLINE | ID: mdl-34116569

ABSTRACT

1,2-unsaturated pyrrolizidine alkaloids are found naturally in Symphytum officinale, well known as comfrey, which has a longstanding use for the topical treatment of painful muscle and joint complaints. Pyrrolizidine alkaloids (PA) are a relevant concern for the safety assessment due to their liver genotoxicity profile, and close attention is paid during manufacturing to minimizing their levels. Current regulatory risk assessment approaches include setting limits that derive from toxicity data coming from the oral route of exposure. This study investigated to what extent pyrrolizidine alkaloids are bioavailable following topical exposure, assessing penetration of retronecine-type PAs in an in vitro human skin model. A single comfrey root formulation was spiked with 3 different congeners (a 7R-monoester, an open-chained 7R-diester, and a cyclic diester) and percutaneous absorption measured per OECD guidelines and good laboratory practices. The measured penetration for all 3 PAs was low and compared favourably with existing in vitro data. Although consideration of different regulatory guidance influences the determination of dermally absorbed dose, these data facilitate the understanding of absorption differences following topical exposure, which in turn can be taken into account in the risk assessment.


Subject(s)
Comfrey , Pyrrolizidine Alkaloids , Humans , Pyrrolizidine Alkaloids/toxicity , Skin , Skin Absorption
9.
Euro Surveill ; 27(48)2022 12.
Article in English | MEDLINE | ID: mdl-36695461

ABSTRACT

Over 79,000 confirmed cases of mpox were notified worldwide between May and November 2022, most of them in men who have sex with men. Cases in women, for whom mpox might pose different risks, are rare, and Spain has reported more than one third of those in Europe. Using surveillance data, our study found similar time trends, but differences in delay of diagnosis, sexual transmission and signs and symptoms between men and women.


Subject(s)
Mpox (monkeypox) , Sexual and Gender Minorities , Male , Female , Humans , Spain/epidemiology , Homosexuality, Male , Mpox (monkeypox)/diagnosis , Mpox (monkeypox)/epidemiology , Europe
11.
Front Pediatr ; 9: 753226, 2021.
Article in English | MEDLINE | ID: mdl-34900862

ABSTRACT

Background: Cerebral Palsy (CP), the most common motor disability in childhood, affects individual's motor skills, movement and posture. This results in limited activity and a low social participation. The ATLAS2030 exoskeleton is a pediatric device that enables gait rehabilitation for children with neurological or neuromuscular pathologies with gait pathology. Purpose: To study changes in relation to range of motion (ROM), strength and spasticity in children with CP after using the ATLAS2030 gait exoskeleton. Methods and Participants: Three children (mean age 8.0 ± 2.0), two girls and one boy, two of them with GMFCS IV and one with GMFCS III, received robot-assisted gait training (RAGT) with ATLAS2030 for one month. Results: The average time of exoskeleton use was 54.7 ± 10.4 min in all sessions, and all participants were able to perform all exercises. The strength of all muscle groups was increased after the 10 sessions for the participants assessed and the limited ROM in the sagittal plane (hip and knee extension and ankle dorsiflexion) decreased after the use of the exoskeleton compared to the initial state. Spasticity was reduced at the end of the sessions after the use of the exoskeleton compared to their initial state. Conclusion: The ROM, spasticity and strength were improved after RAGT with ATLAS2030 exoskeleton in these children with CP. However, further studies with larger samples should be carried out to confirm our findings.

12.
NeuroRehabilitation ; 49(3): 333-348, 2021.
Article in English | MEDLINE | ID: mdl-34219676

ABSTRACT

BACKGROUND: Cerebral Palsy (CP) and Spinal Muscular Atrophy (SMA) are common causes of motor disability in childhood. Gait exoskeletons are currently being used as part of rehabilitation for children with walking difficulties. OBJECTIVE: To assess the safety and efficacy and describe the main characteristics of the clinical articles using robot-assisted gait training (RAGT) with exoskeleton for children with CP or SMA. METHODS: A computer search was conducted in five bibliographic databases regarding clinical studies published in the last ten years. In order to be included in this review for further analysis, the studies had to meet the following criteria: (1) assess efficacy or safety of interventions; (2) population had to be children with CP or SMA aged between 3 and 14; (3) exoskeleton must be bilateral and assist lower limbs during walking. RESULTS: Twenty-one articles were selected, of which only five were clinical trials. 108 participants met the inclusion criteria for this study, all with a diagnosis of CP. The evidence level of the selected papers was commonly low. CONCLUSIONS: RAGT therapy seems to be safe for children with CP. However, further investigation is needed to confirm the results related to efficacy. There is no evidence of RAGT therapy for SMA children.


Subject(s)
Cerebral Palsy , Disabled Persons , Exoskeleton Device , Motor Disorders , Muscular Atrophy, Spinal , Robotics , Adolescent , Child , Child, Preschool , Gait , Humans
13.
PeerJ Comput Sci ; 7: e601, 2021.
Article in English | MEDLINE | ID: mdl-34307858

ABSTRACT

BACKGROUND: After many years of research on software repositories, the knowledge for building mature, reusable tools that perform data retrieval, storage and basic analytics is readily available. However, there is still room to improvement in the area of reusable tools implementing this knowledge. GOAL: To produce a reusable toolset supporting the most common tasks when retrieving, curating and visualizing data from software repositories, allowing for the easy reproduction of data sets ready for more complex analytics, and sparing the researcher or the analyst of most of the tasks that can be automated. METHOD: Use our experience in building tools in this domain to identify a collection of scenarios where a reusable toolset would be convenient, and the main components of such a toolset. Then build those components, and refine them incrementally using the feedback from their use in both commercial, community-based, and academic environments. RESULTS: GrimoireLab, an efficient toolset composed of five main components, supporting about 30 different kinds of data sources related to software development. It has been tested in many environments, for performing different kinds of studies, and providing different kinds of services. It features a common API for accessing the retrieved data, facilities for relating items from different data sources, semi-structured storage for easing later analysis and reproduction, and basic facilities for visualization, preliminary analysis and drill-down in the data. It is also modular, making it easy to support new kinds of data sources and analysis. CONCLUSIONS: We present a mature toolset, widely tested in the field, that can help to improve the situation in the area of reusable tools for mining software repositories. We show some scenarios where it has already been used. We expect it will help to reduce the effort for doing studies or providing services in this area, leading to advances in reproducibility and comparison of results.

14.
Article in English, Spanish | MEDLINE | ID: mdl-34024674

ABSTRACT

BACKGROUND: Clostridioides difficile infection (CDI) is a disease that is potentially preventable by vaccination. A good knowledge of its epidemiology, which can change over time, is warranted for prevention purposes and to help decision-making on the use of vaccines in public health programs. The objective of the research was to determine the epidemiology of healthcare-associated CDI (HA-CDI) and community-associated CDI (CA-CDI) in hospitalized patients in Spain using point prevalence data. METHODS: Point prevalence survey data on infections of hospitalized patients for years 2012-2019 were analyzed. HA-CDI and CA-CDI prevalence rates were calculated. Both HA-CDI and CA-CDI, as well as age group prevalence rates, were examined for trends. Patient comorbidities were tested for association to CDI. RESULTS: The prevalence of CDI in Spanish hospitals has grown exponentially from 14.1% in 2012 to 35.9% in 2019 (cases/10.000 hospitalized patients). Almost two thirds of the cases are of nosocomial onset. This increase was observed for HA-CDI and CA-CDI at an annual rate of 1.11% (CI 95% 1.08-1.15) and 1.09% (CI 95% 1.04-1.13), respectively. Patients 50 years old or older represent 87% of the total number of cases. Patients suffering from neoplasm (OR 1.39), immunodeficiency (OR 3.26), neutropenia (OR 3.70), cirrhosis (OR 1.92) and chronic renal failure (OR 1.91) have a significant increased risk of developing CDI, after adjusting for age. CONCLUSION: In Spain, the prevalence rate of both HA-CDI and CA-CDI have been increasing. Burden of CDI as well as clinical and epidemiological characteristics of CDI patients will help to support public health decision-making.

15.
Int J Mol Sci ; 21(13)2020 Jun 30.
Article in English | MEDLINE | ID: mdl-32630037

ABSTRACT

Preparations of comfrey (Symphytum officinale L.) roots are used topically to reduce inflammation. Comfrey anti-inflammatory and analgesic properties have been proven in clinical studies. However, the bioactive compounds associated with these therapeutic activities are yet to be identified. An LC-ESI-Orbitrap-MSn metabolite profile of a hydroalcoholic extract of comfrey root guided the identification of 20 compounds, including a new arylnaphthalene lignan bearing a rare δ-lactone ring, named comfreyn A. Its structure was determined using extensive 2D NMR and ESI-MS experiments. Additionally, the occurrence of malaxinic acid, caffeic acid ethyl ester, along with the lignans ternifoliuslignan D, 3-carboxy-6,7-dihydroxy-1-(3',4'-dihydroxyphenyl) -naphthalene, globoidnan A and B, and rabdosiin was reported in S. officinale for the first time. These results helped to redefine the metabolite profile of this medicinal plant. Finally, caffeic acid ethyl ester and comfreyn A were found to significantly inhibit E-selectin expression in IL-1ß stimulated human umbilical vein endothelial cells (HUVEC), with EC values of 64 and 50 µM, respectively.


Subject(s)
Comfrey/chemistry , Comfrey/metabolism , Anti-Inflammatory Agents/analysis , Chromatography, Liquid , Human Umbilical Vein Endothelial Cells , Humans , Molecular Structure , Plant Roots/chemistry , Plant Roots/metabolism , Plants, Medicinal/chemistry , Plants, Medicinal/metabolism , Spectrometry, Mass, Electrospray Ionization
16.
Org Lett ; 21(14): 5407-5412, 2019 07 19.
Article in English | MEDLINE | ID: mdl-31184172

ABSTRACT

The structures of five linear lipopeptides, thaxteramides A1, A2, B1, B2, and C isolated from the myxobacterium Jahnella thaxteri, were elucidated. They have a C-terminal common tetrapeptidic Tyr-Gly-ß-Ala-Tyr core but differ in the stereochemistry of the tyrosine units, methylations, the remaining amino acids, and the N-terminal polyketide. In silico analysis of the genome sequence complemented with feeding experiments revealed two distinct hybrid PKS/NRPS gene clusters. Three semisynthesized cyclic analogues were found to inhibit the growth of Gram-positive bacteria.


Subject(s)
Lipopeptides/biosynthesis , Myxococcales/metabolism , Amino Acid Sequence , Computer Simulation , Lipopeptides/chemistry
17.
Front Pharmacol ; 10: 289, 2019.
Article in English | MEDLINE | ID: mdl-31105555

ABSTRACT

Symphytum officinale, commonly known as comfrey, constitutes a traditional medicinal plant with a long-standing therapeutic history, and preparations thereof have been widely used for the treatment of painful muscle and joint complaints, wound and bone healing, and inflammation. Today, its topical use is based on its analgesic and anti-inflammatory effects, which have been substantiated by modern clinical trials. However, the molecular basis of its action remained elusive. Here, we show that a hydroalcoholic extract of comfrey root impairs the development of a pro-inflammatory scenario in primary human endothelial cells in a dose-dependent manner. The extract, and especially its mucilage-depleted fraction, impair the interleukin-1 (IL-1) induced expression of pro-inflammatory markers including E-selectin, VCAM1, ICAM1, and COX-2. Both preparations inhibit the activation of NF-κB, a transcription factor of central importance for the expression of these and other pro-inflammatory genes. Furthermore, our biochemical studies provide evidence that comfrey inhibits NF-κB signaling at two stages: it dampens not only the activation of IKK1/2 and the subsequent IκBα degradation, but also interferes with NF-κB p65 nucleo-cytoplasmatic shuttling and transactivation. These results provide a first mechanistic insight into the mode of action of a century-old popular herbal medicine.

18.
ACS Chem Biol ; 13(1): 267-272, 2018 01 19.
Article in English | MEDLINE | ID: mdl-29220569

ABSTRACT

Analysis of the genome sequence of the myxobacterium Chondromyces crocatus Cm c5 revealed the presence of numerous cryptic megasynthetase gene clusters, one of which we here assign to two previously unknown chlorinated metabolites by a comparative gene inactivation and secondary metabolomics approach. Structure elucidation of these compounds revealed a unique cyclic depsipeptide skeleton featuring ß- and δ-amide bonds of aspartic acid and 3-methyl ornithine moieties, respectively. Insights into their biosynthesis were obtained by targeted gene inactivation and feeding experiments employing isotope-labeled precursors. The compounds were produced ubiquitously by the species Chondromyces crocatus and were found to inhibit the carbon storage regulator-RNA interaction.


Subject(s)
Depsipeptides/metabolism , Myxococcales/genetics , Aspartic Acid/chemistry , Depsipeptides/chemistry , Gene Silencing , Genome, Bacterial , Genomics , Magnetic Resonance Spectroscopy , Metabolomics , Molecular Structure , Multigene Family , Myxococcales/metabolism
19.
J Org Chem ; 82(12): 6032-6043, 2017 06 16.
Article in English | MEDLINE | ID: mdl-28489377

ABSTRACT

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 γ-halogenated piperazic acid, and a novel δ-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 δ 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 µg/mL.


Subject(s)
Peptides/chemistry , Pyridazines/chemistry , Streptomyces/chemistry , Molecular Conformation , Peptides/isolation & purification , Pyridazines/isolation & purification , Stereoisomerism
20.
J Nat Prod ; 78(8): 2023-8, 2015 Aug 28.
Article in English | MEDLINE | ID: mdl-26214047

ABSTRACT

Seven new chromone-containing polyketides, termed cystochromones A-G, were isolated from the myxobacterial strain Cystobacter sp. MCy9104. Their structures were elucidated using comprehensive NMR spectroscopy and HR-MS/MS. Cystochromones bear a pentadecyl moiety unusually attached at C-5 of the chromone ring. Moreover, isotope-labeled substrate feeding experiments and NMR analysis suggested a hybrid iso-fatty acid and polyketide synthase biosynthetic pathway for these secondary metabolites.


Subject(s)
Chromones/chemistry , Chromones/isolation & purification , Myxococcales/chemistry , Polyketides/chemistry , Polyketides/isolation & purification , Isotope Labeling , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Philippines , Polyketide Synthases/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL
...