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1.
EMBO J ; 43(7): 1187-1213, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38383863

RESUMEN

Histone modifications commonly integrate environmental cues with cellular metabolic outputs by affecting gene expression. However, chromatin modifications such as acetylation do not always correlate with transcription, pointing towards an alternative role of histone modifications in cellular metabolism. Using an approach that integrates mass spectrometry-based histone modification mapping and metabolomics with stable isotope tracers, we demonstrate that elevated lipids in acetyltransferase-depleted hepatocytes result from carbon atoms derived from deacetylation of hyperacetylated histone H4 flowing towards fatty acids. Consistently, enhanced lipid synthesis in acetyltransferase-depleted hepatocytes is dependent on histone deacetylases and acetyl-CoA synthetase ACSS2, but not on the substrate specificity of the acetyltransferases. Furthermore, we show that during diet-induced lipid synthesis the levels of hyperacetylated histone H4 decrease in hepatocytes and in mouse liver. In addition, overexpression of acetyltransferases can reverse diet-induced lipogenesis by blocking lipid droplet accumulation and maintaining the levels of hyperacetylated histone H4. Overall, these findings highlight hyperacetylated histones as a metabolite reservoir that can directly contribute carbon to lipid synthesis, constituting a novel function of chromatin in cellular metabolism.


Asunto(s)
Carbono , Histonas , Animales , Ratones , Histonas/metabolismo , Carbono/metabolismo , Lipogénesis , Cromatina , Acetiltransferasas/metabolismo , Lípidos , Acetilación , Histona Acetiltransferasas/genética , Histona Acetiltransferasas/metabolismo
2.
PLoS Pathog ; 17(5): e1009486, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-34015060

RESUMEN

Vitellogenesis and oocyte maturation require anautogenous female Anopheles mosquitoes to obtain a bloodmeal from a vertebrate host. The bloodmeal is rich in proteins that are readily broken down into amino acids in the midgut lumen and absorbed by the midgut epithelial cells where they are converted into lipids and then transported to other tissues including ovaries. The stearoyl-CoA desaturase (SCD) plays a pivotal role in this process by converting saturated (SFAs) to unsaturated (UFAs) fatty acids; the latter being essential for maintaining cell membrane fluidity amongst other housekeeping functions. Here, we report the functional and phenotypic characterization of SCD1 in the malaria vector mosquito Anopheles coluzzii. We show that RNA interference (RNAi) silencing of SCD1 and administration of sterculic acid (SA), a small molecule inhibitor of SCD1, significantly impact on the survival and reproduction of female mosquitoes following blood feeding. Microscopic observations reveal that the mosquito thorax is quickly filled with blood, a phenomenon likely caused by the collapse of midgut epithelial cell membranes, and that epithelial cells are depleted of lipid droplets and oocytes fail to mature. Transcriptional profiling shows that genes involved in protein, lipid and carbohydrate metabolism and immunity-related genes are the most affected by SCD1 knock down (KD) in blood-fed mosquitoes. Metabolic profiling reveals that these mosquitoes exhibit increased amounts of saturated fatty acids and TCA cycle intermediates, highlighting the biochemical framework by which the SCD1 KD phenotype manifests as a result of a detrimental metabolic syndrome. Accumulation of SFAs is also the likely cause of the potent immune response observed in the absence of infection, which resembles an auto-inflammatory condition. These data provide insights into mosquito bloodmeal metabolism and lipid homeostasis and could inform efforts to develop novel interventions against mosquito-borne diseases.


Asunto(s)
Alimentación Animal/análisis , Anopheles/crecimiento & desarrollo , Conducta Alimentaria , Mosquitos Vectores/fisiología , Reproducción , Estearoil-CoA Desaturasa/metabolismo , Animales , Anopheles/enzimología , Anopheles/inmunología , Femenino , Perfilación de la Expresión Génica , Mosquitos Vectores/parasitología , Estearoil-CoA Desaturasa/genética
3.
Microb Ecol ; 86(2): 1438-1441, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-36112189

RESUMEN

Water is the most indispensable natural resource; yet, organic pollution of freshwater sources is widespread. In recent years, there has been increasing concern over the vast array of emerging organic contaminants (EOCs) in the effluent of wastewater treatment plants (WWTPs). Several of these EOCs are degraded within the pore space of riverbeds by active microbial consortia. However, the mechanisms behind this ecosystem service are largely unknown. Here, we report how phosphate concentration and predator-prey interactions drive the capacity of bacteria to process a model EOC (ibuprofen). The presence of phosphate had a significant positive effect on the population growth rate of an ibuprofen-degrading strain. Thus, when phosphate was present, ibuprofen removal efficiency increased. Moreover, low and medium levels of predation, by a ciliated protozoan, stimulated bacterial population growth. This unimodal effect of predation was lost under high phosphate concentration, resulting in the flattening of the relationships between predator density and population growth of ibuprofen degraders. Our results suggest that moderate nutrient and predation levels promote the growth rate of bacterial degraders and, consequently, the self-purifying capability of the system. These findings enhance our understanding of the mechanisms by which riverbed communities drive the processing of EOCs.


Asunto(s)
Ecosistema , Cadena Alimentaria , Animales , Ibuprofeno/metabolismo , Conducta Predatoria , Bacterias/metabolismo
4.
Int J Mol Sci ; 24(18)2023 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-37762412

RESUMEN

Wholegrains contain both fibre and phenolic acids (PAs), and their gastrointestinal modifications are critical for their bioavailability and bioactivity. We evaluated the modifications on the PA profile and gut microbiota composition of selected Nigerian wholegrains, following cooking and gastrointestinal digestion. Red fonio, red millet, red sorghum, and white corn were cooked, digested, and fermented using an in vitro colonic model. A total of 26 PA derivatives were quantified in soluble and bound fractions using Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry (UPLC-MS/MS) analysis. DNA samples were analysed using 16S rRNA amplicon sequencing to profile the microbiota composition. The results show that cooking and digestion significantly affected the levels of PAs in all grains (p ≤ 0.05) compared to raw grains. Colonic fermentation resulted in a peak of total soluble PAs at 4-6 h for red sorghum and white corn and at 24 h for red millet and red fonio. Enterobacteriaceae genera were the most abundant at 24 h in all grains studied. 3-hydroxybenzaldehyde correlated positively with the relative abundance of Dorea and the mucus-degrader bacteria Akkermansia (p ≤ 0.05), whereas hydroferulic acid and isoferulic acid levels correlated negatively with Oscillospira and Ruminococcus (p ≤ 0.05), respectively. Our data indicate that cooking, digestion, and colonic fermentation affect the release of bound PAs from wholegrains and, consequently, their metabolic conversion. Furthermore, PA fermentation in the gut is associated with potentially relevant changes in the microbiota. This in vitro study provides the basis for the design of an in vivo human intervention study that can confirm the trends herein observed but also assess the impact on health outcomes.


Asunto(s)
Microbioma Gastrointestinal , Humanos , Fermentación , Cromatografía Liquida , ARN Ribosómico 16S/genética , ARN Ribosómico 16S/análisis , Espectrometría de Masas en Tándem , Culinaria , Grano Comestible/genética , Digestión
5.
J Physiol ; 600(20): 4393-4408, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36054466

RESUMEN

Whole-body euglycaemia is partly maintained by two cellular processes that encourage glucose uptake in skeletal muscle, the insulin- and contraction-stimulated pathways, with research suggesting convergence between these two processes. The normal structural integrity of the skeletal muscle requires an intact actin cytoskeleton as well as integrin-associated proteins, and thus those structures are likely fundamental for effective glucose uptake in skeletal muscle. In contrast, excessive extracellular matrix (ECM) remodelling and integrin expression in skeletal muscle may contribute to insulin resistance owing to an increased physical barrier causing reduced nutrient and hormonal flux. This review explores the role of the ECM and the actin cytoskeleton in insulin- and contraction-mediated glucose uptake in skeletal muscle. This is a clinically important area of research given that defects in the structural integrity of the ECM and integrin-associated proteins may contribute to loss of muscle function and decreased glucose uptake in type 2 diabetes.


Asunto(s)
Diabetes Mellitus Tipo 2 , Glucosa , Diabetes Mellitus Tipo 2/metabolismo , Matriz Extracelular/metabolismo , Glucosa/metabolismo , Humanos , Insulina/metabolismo , Integrinas/metabolismo , Músculo Esquelético/metabolismo
6.
Arch Toxicol ; 93(2): 341-353, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30552463

RESUMEN

Acetaminophen (APAP) is one of the most commonly used analgesics worldwide, and overdoses are associated with lactic acidosis, hepatocyte toxicity, and acute liver failure due to oxidative stress and mitochondrial dysfunction. Hepatoma cell lines typically lack the CYP450 activity to generate the reactive metabolite of APAP observed in vivo, but are still subject to APAP cytotoxicity. In this study, we employed metabolic profiling and isotope labelling approaches to investigate the metabolic impact of acute exposure to cytotoxic doses of APAP on the widely used HepG2 cell model. We found that APAP exposure leads to limited cellular death and substantial growth inhibition. Metabolically, we observed an up-regulation of glycolysis and lactate production with a concomitant reduction in carbon from glucose entering the pentose-phosphate pathway and the TCA cycle. This was accompanied by a depletion of cellular NADPH and a reduction in the de novo synthesis of fatty acids and the amino acids serine and glycine. These events were not associated with lower reduced glutathione levels and no glutathione conjugates were seen in cell extracts. Co-treatment with a specific inhibitor of the lactate/H+ transporter MCT1, AZD3965, led to increased apoptosis in APAP-treated cells, suggesting that lactate accumulation could be a cause of cell death in this model. In conclusion, we show that APAP toxicity in HepG2 cells is largely independent of oxidative stress, and is linked instead to a decoupling of glycolysis from the TCA cycle, lactic acidosis, reduced NADPH production, and subsequent suppression of the anabolic pathways required for rapid growth.


Asunto(s)
Acetaminofén/toxicidad , Glucólisis/efectos de los fármacos , Metabolismo/efectos de los fármacos , NADP/metabolismo , Supervivencia Celular/efectos de los fármacos , Ciclo del Ácido Cítrico/efectos de los fármacos , Sinergismo Farmacológico , Glutatión/metabolismo , Células Hep G2 , Humanos , Lactatos/metabolismo , Transportadores de Ácidos Monocarboxílicos/antagonistas & inhibidores , Transportadores de Ácidos Monocarboxílicos/metabolismo , Pirimidinonas/toxicidad , Simportadores/antagonistas & inhibidores , Simportadores/metabolismo , Tiofenos/toxicidad , Pruebas de Toxicidad
8.
Biophys J ; 112(10): 2219-2230, 2017 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-28538158

RESUMEN

Ammonium assimilation in Escherichia coli is regulated by two paralogous proteins (GlnB and GlnK), which orchestrate interactions with regulators of gene expression, transport proteins, and metabolic pathways. Yet how they conjointly modulate the activity of glutamine synthetase, the key enzyme for nitrogen assimilation, is poorly understood. We combine experiments and theory to study the dynamic roles of GlnB and GlnK during nitrogen starvation and upshift. We measure time-resolved in vivo concentrations of metabolites, total and posttranslationally modified proteins, and develop a concise biochemical model of GlnB and GlnK that incorporates competition for active and allosteric sites, as well as functional sequestration of GlnK. The model predicts the responses of glutamine synthetase, GlnB, and GlnK under time-varying external ammonium level in the wild-type and two genetic knock-outs. Our results show that GlnK is tightly regulated under nitrogen-rich conditions, yet it is expressed during ammonium run-out and starvation. This suggests a role for GlnK as a buffer of nitrogen shock after starvation, and provides a further functional link between nitrogen and carbon metabolisms.


Asunto(s)
Proteínas de Escherichia coli/metabolismo , Nitrógeno/metabolismo , Nucleotidiltransferasas/metabolismo , Proteínas PII Reguladoras del Nitrógeno/metabolismo , Algoritmos , Compuestos de Amonio/metabolismo , Proteínas de Transporte de Catión/metabolismo , Escherichia coli , Proteínas de Escherichia coli/genética , Técnicas de Inactivación de Genes , Modelos Biológicos , Nitrógeno/deficiencia , Nucleotidiltransferasas/genética , Proteínas PII Reguladoras del Nitrógeno/genética , Estrés Fisiológico
9.
Plant Cell Physiol ; 57(1): 82-94, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26574578

RESUMEN

Under anoxic conditions the green alga Chlamydomonas reinhardtii activates various fermentation pathways leading to the creation of formate, acetate, ethanol and small amounts of other metabolites including d-lactate and hydrogen. Progress has been made in identifying the enzymes involved in these pathways and their subcellular locations; however, the identity of the enzyme involved in reducing pyruvate to d-lactate has remained unclear. Based on sequence comparisons, enzyme activity measurements, X-ray crystallography, biochemical fractionation and analysis of knock-down mutants, we conclude that pyruvate reduction in the chloroplast is catalyzed by a tetrameric NAD(+)-dependent d-lactate dehydrogenase encoded by Cre07.g324550. Its expression during aerobic growth supports a possible function as a 'lactate valve' for the export of lactate to the mitochondrion for oxidation by cytochrome-dependent d-lactate dehydrogenases and by glycolate dehydrogenase. We also present a revised spatial model of fermentation based on our immunochemical detection of the likely pyruvate decarboxylase, PDC3, in the cytoplasm.


Asunto(s)
Chlamydomonas reinhardtii/enzimología , Lactato Deshidrogenasas/metabolismo , Piruvatos/metabolismo , Proteínas Algáceas/genética , Proteínas Algáceas/metabolismo , Chlamydomonas reinhardtii/genética , Cloroplastos/enzimología , Cloroplastos/genética , Fermentación , Lactato Deshidrogenasas/genética , Modelos Biológicos , Modelos Estructurales , Oxidación-Reducción , Piruvato Descarboxilasa/genética , Piruvato Descarboxilasa/metabolismo
10.
Environ Microbiol ; 18(3): 807-18, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26568055

RESUMEN

The Crc protein, together with the Hfq protein, participates in catabolite repression in pseudomonads, helping to coordinate metabolism. Little is known about how Crc affects the hierarchy of metabolite assimilation from complex mixtures. Using proton Nuclear Magnetic Resonance (NMR) spectroscopy, we carried out comprehensive metabolite profiling of culture supernatants (metabolic footprinting) over the course of growth of both Pseudomonas putida and P. aeruginosa, and compared the wild-type strains with deletion mutants for crc. A complex metabolite consumption hierarchy was observed, which was broadly similar between the two species, although with some important differences, for example in sugar utilization. The order of metabolite utilization changed upon inactivation of the crc gene, but even in the Crc-null strains some compounds were completely consumed before late metabolites were taken up. This suggests the presence of additional regulatory elements that determine the time and order of consumption of compounds. Unexpectedly, the loss of Crc led both species to excrete acetate and pyruvate as a result of unbalanced growth during exponential phase, compounds that were later consumed in stationary phase. This loss of carbon during growth helps to explain the contribution of the Crc/Hfq regulatory system to evolutionary fitness of pseudomonads.


Asunto(s)
Proteínas Bacterianas/metabolismo , Carbono/metabolismo , Pseudomonas aeruginosa/metabolismo , Pseudomonas putida/metabolismo , Pseudomonas/metabolismo , Proteínas Represoras/metabolismo , Represión Catabólica/genética , Medios de Cultivo , Proteína de Factor 1 del Huésped/metabolismo , Pseudomonas aeruginosa/genética , Pseudomonas putida/genética
11.
PLoS Biol ; 10(5): e1001330, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22615541

RESUMEN

Studies of evolutionary responses to novel environments typically consider single species or perhaps pairs of interacting species. However, all organisms co-occur with many other species, resulting in evolutionary dynamics that might not match those predicted using single species approaches. Recent theories predict that species interactions in diverse systems can influence how component species evolve in response to environmental change. In turn, evolution might have consequences for ecosystem functioning. We used experimental communities of five bacterial species to show that species interactions have a major impact on adaptation to a novel environment in the laboratory. Species in communities diverged in their use of resources compared with the same species in monocultures and evolved to use waste products generated by other species. This generally led to a trade-off between adaptation to the abiotic and biotic components of the environment, such that species evolving in communities had lower growth rates when assayed in the absence of other species. Based on growth assays and on nuclear magnetic resonance (NMR) spectroscopy of resource use, all species evolved more in communities than they did in monocultures. The evolutionary changes had significant repercussions for the functioning of these experimental ecosystems: communities reassembled from isolates that had evolved in polyculture were more productive than those reassembled from isolates that had evolved in monoculture. Our results show that the way in which species adapt to new environments depends critically on the biotic environment of co-occurring species. Moreover, predicting how functioning of complex ecosystems will respond to an environmental change requires knowing how species interactions will evolve.


Asunto(s)
Adaptación Fisiológica , Bacterias/crecimiento & desarrollo , Evolución Biológica , Ambiente , Interacciones Microbianas , Bacterias/aislamiento & purificación , Fenómenos Fisiológicos Bacterianos , Técnicas Bacteriológicas , Biota , Técnicas de Cultivo , Espectroscopía de Resonancia Magnética , Método de Montecarlo , Análisis de Componente Principal
12.
J Biol Chem ; 288(21): 15098-109, 2013 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-23572517

RESUMEN

Metabolic footprinting of supernatants has been proposed as a tool for assigning gene function. We used NMR spectroscopy to measure the exometabolome of 86 single-gene transposon insertion mutant strains (mutants from central carbon metabolism and regulatory mutants) of the opportunistic pathogen Pseudomonas aeruginosa, grown on a medium designed to represent the nutritional content of cystic fibrosis sputum. Functionally related genes had similar metabolic profiles. E.g. for two-component system mutants, the cognate response regulator and sensor kinase genes clustered tightly together. Some strains had metabolic phenotypes (metabotypes) that could be related to the known gene function. E.g. pyruvate dehydrogenase mutants accumulated large amounts of pyruvate in the medium. In other cases, the metabolic phenotypes were not easily interpretable. The rpoN mutant, which lacks the alternative σ factor RpoN (σ(54)), accumulated high levels of gluconate in the medium. In addition, endometabolome profiling of intracellular metabolites identified a number of systemic metabolic changes. We linked this to indirect regulation of the catabolite repression protein Crc via the non-coding RNA crcZ and found that a crcZ (but not crc) mutant also shared the high-gluconate phenotype. We profiled an additional set of relevant metabolic enzymes and transporters, including Crc targets, and showed that the Crc-regulated edd mutant (gluconate-6-phosphate dehydratase) had similar gluconate levels as the rpoN mutant. Finally, a set of clinical isolates showed patient- and random amplification of polymorphic DNA (RAPD) type-specific differences in gluconate production, which were associated significantly with resistance across four antibiotics (tobramycin, ciprofloxacin, aztreonam, and imipenem), indicating that this has potential clinical relevance.


Asunto(s)
Proteínas Bacterianas/metabolismo , Fibrosis Quística/microbiología , Gluconatos/metabolismo , Metaboloma , Infecciones por Pseudomonas/metabolismo , Pseudomonas aeruginosa/metabolismo , Proteínas Bacterianas/genética , Fibrosis Quística/patología , Farmacorresistencia Bacteriana/fisiología , Femenino , Humanos , Masculino , Infecciones por Pseudomonas/genética , Infecciones por Pseudomonas/patología , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/aislamiento & purificación , Técnica del ADN Polimorfo Amplificado Aleatorio
13.
Anal Chem ; 86(13): 6555-62, 2014 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-24896667

RESUMEN

Rapid evaporative ionization mass spectrometry (REIMS) was investigated for its suitability as a general identification system for bacteria and fungi. Strains of 28 clinically relevant bacterial species were analyzed in negative ion mode, and corresponding data was subjected to unsupervised and supervised multivariate statistical analyses. The created supervised model yielded correct cross-validation results of 95.9%, 97.8%, and 100% on species, genus, and Gram-stain level, respectively. These results were not affected by the resolution of the mass spectral data. Blind identification tests were performed for strains cultured on different culture media and analyzed using different instrumental platforms which led to 97.8-100% correct identification. Seven different Escherichia coli strains were subjected to different culture conditions and were distinguishable with 88% accuracy. In addition, the technique proved suitable to distinguish five pathogenic Candida species with 98.8% accuracy without any further modification to the experimental workflow. These results prove that REIMS is sufficiently specific to serve as a culture condition-independent tool for the identification and characterization of microorganisms.


Asunto(s)
Bacterias/química , Infecciones Bacterianas/microbiología , Candidiasis/microbiología , Espectrometría de Masas/instrumentación , Levaduras/química , Aerosoles/química , Bacterias/clasificación , Humanos , Espectrometría de Masas/economía , Factores de Tiempo , Volatilización , Levaduras/clasificación
15.
Appl Environ Microbiol ; 79(7): 2467-70, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23354718

RESUMEN

We grew Pseudomonas aeruginosa in LB and artificial sputum medium (ASM) (filtered and unfiltered) and quantified metabolite utilization and excretion by nuclear magnetic resonance (NMR) spectroscopy (metabolic footprinting or extracellular metabolomics). Utilization rates were similar between media, but there were differences in excretion-e.g., acetate was produced only in unfiltered ASM.


Asunto(s)
Modelos Teóricos , Pseudomonas aeruginosa/crecimiento & desarrollo , Pseudomonas aeruginosa/metabolismo , Esputo/microbiología , Medios de Cultivo/química , Espectroscopía de Resonancia Magnética , Metaboloma
16.
Artículo en Inglés | MEDLINE | ID: mdl-36721386

RESUMEN

Cerrado and Pantanal plants can provide fruits with high nutritional value and antioxidants. This study aims to evaluate four fruit flours (from jatobá pulp, cumbaru almond, bocaiuva pulp and bocaiuva almond) and their effects on the gut microbiota in healthy (HD) and post-COVID-19 individuals (PC). An in vitro batch system was carried out, the microbiota was analysed by 16S rRNA amplicon sequencing and the short-chain fatty acids ratio was determined. Furthermore, the effect of jatobá pulp flour oil (JAO) on cell viability, oxidative stress and DNA damage was investigated in a myelo-monocytic cell line. Beyond confirming a microbiota imbalance in PC, we identified flour-specific effects: (i) reduction of Veillonellaceae with jatobá extract in PC samples; (ii) decrease in Akkermansia with jatoba and cumbaru flours; (iii) decreasing trend of Faecalibacterium and Ruminococcus with all flours tested, with the exception of the bocaiuva almond in HD samples for Ruminococcus and (iv) increase in Lactobacillus and Bifidobacterium in PC samples with bocaiuva almond flour. JAO displayed antioxidant properties protecting cells from daunorubicin-induced cytotoxicity, oxidative stress and DNA damage. The promising microbiota-modulating abilities of some flours and the chemopreventive effects of JAO deserve to be further explored in human intervention studies.

17.
J Proteome Res ; 11(7): 3888-96, 2012 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-22650367

RESUMEN

Nitrogen is an essential element for bacterial growth, and as such, bacteria have evolved several pathways to assimilate nitrogen and adapt to situations of nitrogen limitation. However, the adaptation of mycobacteria to nitrogen stress and the regulation of the stress response pathways is unknown. Identification of key metabolites produced by mycobacteria during nitrogen stress could therefore provide important insights into mycobacterial survival strategies. Here we used NMR-based metabolomics to monitor and quantify intracellular and extracellular metabolite levels (metabolic footprinting) in Mycobacterium smegmatis grown under nitrogen-limiting and nitrogen-rich conditions. There were several metabolic differences between the two conditions: following nitrogen run-out, there was an increase in intracellular α-ketoglutarate and a decrease in intracellular glutamine and glutamate levels. In addition, a sugar-derived compound accumulated in nitrogen-starved cells that was subsequently assigned as glucosylglycerate (GGA). Free GGA production was responsive to nitrogen stress in M. smegmatis but not to oxidative or osmotic stress; lack of a functional GGA synthesis pathway slightly reduced growth and decreased ammonium uptake rates under nitrogen-limiting conditions. Hence, GGA could contribute to the fitness of mycobacteria under nitrogen limitation.


Asunto(s)
Glucósidos/metabolismo , Ácidos Glicéricos/metabolismo , Mycobacterium smegmatis/metabolismo , Nitrógeno/deficiencia , Estrés Fisiológico , Biomarcadores/metabolismo , Ácido Glutámico/metabolismo , Ácidos Cetoglutáricos/metabolismo , Mycobacterium smegmatis/crecimiento & desarrollo , Mycobacterium smegmatis/fisiología , Nitrógeno/fisiología , Trehalosa/metabolismo
18.
Life (Basel) ; 12(12)2022 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-36556318

RESUMEN

The Gram-negative bacterium Pseudomonas aeruginosa can cause infections in a broad range of hosts including plants, invertebrates and mammals and is an important source of nosocomial infections in humans. We were interested in how differences in the bacteria's nutritional environment impact bacterial communication and virulence factor production. We grew P. aeruginosa in 96 different conditions in BIOLOG Gen III plates and assayed quorum sensing (QS) signaling over the course of growth. We also quantified pyocyanin and biofilm production and the impact of sub-inhibitory exposure to tobramycin. We found that while 3-oxo-C12 homoserine lactone remained the dominant QS signal to be produced, timing of PQS production differed between media types. Further, whether cells grew predominantly as biofilms or planktonic cells was highly context dependent. Our data suggest that understanding the impact of the nutritional environment on the bacterium can lead to valuable insights into the link between bacterial physiology and pathology.

19.
Life (Basel) ; 12(5)2022 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-35629438

RESUMEN

The Authors wish to make the following corrections to this paper [...].

20.
Anal Chem ; 83(22): 8683-7, 2011 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-21988367

RESUMEN

Nuclear magnetic resonance (NMR) spectroscopy is widely used as an analytical platform for metabolomics. Many studies make use of 1D spectra, which have the advantages of relative simplicity and rapid acquisition times. The spectral data can then be analyzed either with a chemometric workflow or by an initial deconvolution or fitting step to generate a list of identified metabolites and associated sample concentrations. Various software tools exist to simplify the fitting process, but at least for 1D spectra, this still requires a degree of skilled operator input. It is of critical importance that we know how much person-to-person variability affects the results, in order to be able to judge between different studies. Here we tested a commercially available software package (Chenomx' NMR Suite) for fitting metabolites to a set of NMR spectra of yeast extracts and compared the output of five different people for both metabolite identification and quantitation. An initial comparison showed good agreement for a restricted set of common metabolites with characteristic well-resolved resonances but wide divergence in the overall identities and number of compounds fitted; refitting according to an agreed set of metabolites and spectral processing approach increased the total number of metabolites fitted but did not dramatically increase the quality of the metabolites that could be fitted without prior knowledge about peak identity. Hence, robust peak assignments are required in advance of manual deconvolution, when the widest range of metabolites is desired. However, very low concentration metabolites still had high coefficients of variation even with shared information on peak assignment. Overall, the effect of the person was less than the experimental group (in this case, sampling method) for almost all of the metabolites.


Asunto(s)
Metabolómica , Humanos , Espectroscopía de Resonancia Magnética , Programas Informáticos
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