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1.
J Nurs Adm ; 50(6): 310-313, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32433111

RESUMEN

OBJECTIVE: A physician-nurse shadow program was established to improve interdisciplinary collaboration. BACKGROUND: Ineffective communication between physicians and nurses leads to poor outcomes in patient satisfaction, safety, and associate engagement. Physician unfamiliarity of the nursing process is identified as a root cause. METHODS: First-year resident physicians shadowed nurses for a 4-hour shift. Residents did not function as a physician during the shadowing experience but participated in nursing workflow and tasks. Participants completed a Likert-scale rating and qualitative survey before and after the shift. RESULTS: The survey measured confidence in communication and perception of workflow. Confidence levels increased in all areas by 29% for residents and 34% for nurses. Data demonstrated improved physician understanding of nursing workflow and inspired recommendations to enhance communication. CONCLUSIONS: First-year resident physicians practiced direct communication skills and experienced hands-on nursing care during the shadow program. The initiative provided an environment for mutual learning and interdisciplinary relationship-building.


Asunto(s)
Comunicación , Internado y Residencia , Rol de la Enfermera , Grupo de Atención al Paciente , Médicos , Femenino , Humanos , Masculino , Satisfacción del Paciente , Relaciones Médico-Enfermero , Encuestas y Cuestionarios , Flujo de Trabajo
2.
J Immunol ; 198(1): 318-334, 2017 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-27852744

RESUMEN

Candida albicans infection produces elongated hyphae resistant to phagocytic clearance compelling alternative neutrophil effector mechanisms to destroy these physically large microbial structures. Additionally, all tissue-based neutrophilic responses to fungal infections necessitate contact with the extracellular matrix (ECM). Neutrophils undergo a rapid, ECM-dependent mechanism of homotypic aggregation and NETosis in response to C. albicans mediated by the ß2 integrin, complement receptor 3 (CR3, CD11b/CD18, αMß2). Neither homotypic aggregation nor NETosis occurs when human neutrophils are exposed either to immobilized fungal ß-glucan or to C. albicans hyphae without ECM. The current study provides a mechanistic basis to explain how matrix controls the antifungal effector functions of neutrophils under conditions that preclude phagocytosis. We show that CR3 ligation initiates a complex mechanism of integrin cross-talk resulting in differential regulation of the ß1 integrins VLA3 (α3ß1) and VLA5 (α5ß1). These ß1 integrins control distinct antifungal effector functions in response to either fungal ß-glucan or C. albicans hyphae and fibronectin, with VLA3 inducing homotypic aggregation and VLA5 regulating NETosis. These integrin-dependent effector functions are controlled temporally whereby VLA5 and CR3 induce rapid, focal NETosis early after binding fibronectin and ß-glucan. Within minutes, CR3 undergoes inside-out auto-activation that drives the downregulation of VLA5 and the upregulation of VLA3 to support neutrophil swarming and aggregation. Forcing VLA5 to remain in the activated state permits NETosis but prevents homotypic aggregation. Therefore, CR3 serves as a master regulator during the antifungal neutrophil response, controlling the affinity states of two different ß1 integrins, which in turn elicit distinct effector functions.


Asunto(s)
Matriz Extracelular/inmunología , Trampas Extracelulares/inmunología , Integrina alfa3beta1/inmunología , Neutrófilos/inmunología , beta-Glucanos/inmunología , Candida albicans/inmunología , Separación Celular , Transferencia Resonante de Energía de Fluorescencia , Proteínas Fúngicas/inmunología , Humanos , Antígeno de Macrófago-1/inmunología , Microscopía Electrónica de Rastreo , Receptor Cross-Talk/inmunología
3.
J Immunol ; 190(8): 4136-48, 2013 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-23509360

RESUMEN

The armament of neutrophil-mediated host defense against pathogens includes the extrusion of a lattice of DNA and microbicidal enzymes known as neutrophil extracellular traps (NETs). The receptor/ligand interactions and intracellular signaling mechanisms responsible for elaborating NETs were determined for the response to Candida albicans. Because the host response of extravasated neutrophils to mycotic infections within tissues necessitates contact with extracellular matrix, this study also identified a novel and significant regulatory role for the ubiquitous matrix component fibronectin (Fn) in NET release. We report that recognition of purified fungal pathogen-associated molecular pattern ß-glucan by human neutrophils causes rapid (≤ 30 min) homotypic aggregation and NET release by a mechanism that requires Fn. Alone, immobilized ß-glucan induces reactive oxygen species (ROS) production but not NET release, whereas in the context of Fn, ROS production is suppressed and NETs are extruded. NET release to Fn with ß-glucan is robust, accounting for 17.2 ± 3.4% of total DNA in the cell population. Release is dependent on ß-glucan recognition by complement receptor 3 (CD11b/CD18), but not Dectin-1, or ROS. The process of NET release included filling of intracellular vesicles with nuclear material that was eventually extruded. We identify a role for ERK in homotypic aggregation and NET release. NET formation to C. albicans hyphae was also found to depend on ß-glucan recognition by complement receptor 3, require Fn and ERK but not ROS, and result in hyphal destruction. We report a new regulatory mechanism of NETosis in which the extracellular matrix is a key component of the rapid antifungal response.


Asunto(s)
Candida albicans/inmunología , Matriz Extracelular/inmunología , Neutrófilos/inmunología , Neutrófilos/metabolismo , Candida albicans/citología , Candida albicans/metabolismo , Agregación Celular/inmunología , Matriz Extracelular/metabolismo , Fibronectinas/fisiología , Humanos , Antígeno de Macrófago-1 , Neutrófilos/citología , Especies Reactivas de Oxígeno/inmunología , Especies Reactivas de Oxígeno/metabolismo , Estallido Respiratorio/inmunología , Factores de Tiempo , beta-Glucanos/metabolismo
4.
J Ind Microbiol Biotechnol ; 40(7): 725-34, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23645383

RESUMEN

Clostridium thermocellum is a thermophilic, cellulolytic anaerobe that is a candidate microorganism for industrial biofuels production. Strains with mutations in genes associated with production of L-lactate (Δldh) and/or acetate (Δpta) were characterized to gain insight into the intracellular processes that convert cellobiose to ethanol and other fermentation end-products. Cellobiose-grown cultures of the Δldh strain had identical biomass accumulation, fermentation end-products, transcription profile, and intracellular metabolite concentrations compared to its parent strain (DSM1313 Δhpt Δspo0A). The Δpta-deficient strain grew slower and had 30 % lower final biomass concentration compared to the parent strain, yet produced 75 % more ethanol. A Δldh Δpta double-mutant strain evolved for faster growth had a growth rate and ethanol yield comparable to the parent strain, whereas its biomass accumulation was comparable to Δpta. Free amino acids were secreted by all examined strains, with both Δpta strains secreting higher amounts of alanine, valine, isoleucine, proline, glutamine, and threonine. Valine concentration for Δldh Δpta reached 5 mM by the end of growth, or 2.7 % of the substrate carbon utilized. These secreted amino acid concentrations correlate with increased intracellular pyruvate concentrations, up to sixfold in the Δpta and 16-fold in the Δldh Δpta strain. We hypothesize that the deletions in fermentation end-product pathways result in an intracellular redox imbalance, which the organism attempts to relieve, in part by recycling NADP⁺ through increased production of amino acids.


Asunto(s)
Clostridium thermocellum/metabolismo , Fermentación , Ácido Acético/metabolismo , Aminoácidos/metabolismo , Bacterias Anaerobias/genética , Bacterias Anaerobias/crecimiento & desarrollo , Bacterias Anaerobias/metabolismo , Biomasa , Celobiosa/metabolismo , Clostridium thermocellum/genética , Clostridium thermocellum/crecimiento & desarrollo , Etanol/metabolismo , Ácido Láctico/metabolismo
5.
JID Innov ; 3(6): 100219, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-38116332

RESUMEN

Mycosis fungoides/Sézary syndrome (MF/SS) produces a low-grade chronic inflammatory state that may be associated with an increased risk of cardiovascular (CV) events, as seen in other chronic, systemic dermatologic diseases. To assess this association, a retrospective, cross-sectional study was designed in which 421 patients with a biopsy-proven diagnosis of MF/SS were compared with a control cohort of 4,210 age-, gender-, and race-matched patients randomly selected from the National Health and Nutritional Evaluation Survey database. The MF/SS cohort had a 14% prevalence of CV events, which was not statistically different from the control population's prevalence of 13%. In the MF/SS cohort, a multivariable logistic regression model showed that older patients (OR = 1.05 for each year of age, 95% confidence interval = 1.02-1.07) and those diagnosed with hypertension (OR = 3.40, 95% confidence interval = 1.71-6.75) had a higher risk of a CV event (P < 0.001). Risk factors such as gender, race, smoking, diabetes, and obesity were not significantly associated with CV events. Findings suggest that in the MF/SS population, advancing age and hypertension are risk factors for CV events, requiring clinical recognition and management. In addition, further research is needed to understand the complex interplay of how chronic inflammation in MF/SS impacts the immune development of CV disease.

7.
J Bacteriol ; 194(21): 5991-3, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23045501

RESUMEN

To aid in the investigation of the Populus deltoides microbiome, we generated draft genome sequences for 21 Pseudomonas strains and 19 other diverse bacteria isolated from Populus deltoides roots. Genome sequences for isolates similar to Acidovorax, Bradyrhizobium, Brevibacillus, Caulobacter, Chryseobacterium, Flavobacterium, Herbaspirillum, Novosphingobium, Pantoea, Phyllobacterium, Polaromonas, Rhizobium, Sphingobium, and Variovorax were generated.


Asunto(s)
Bacterias/genética , ADN Bacteriano/química , ADN Bacteriano/genética , Genoma Bacteriano , Análisis de Secuencia de ADN , Bacterias/aislamiento & purificación , Endófitos/genética , Endófitos/aislamiento & purificación , Metagenoma , Datos de Secuencia Molecular , Raíces de Plantas/microbiología , Populus/microbiología , Rizosfera , Microbiología del Suelo
8.
J Bacteriol ; 194(12): 3279-80, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22628508

RESUMEN

Microbacterium laevaniformans strain OR221 was isolated from subsurface sediments obtained from the Field Research Center (FRC) in Oak Ridge, TN. It was characterized as a bacterium tolerant to heavy metals, such as uranium, nickel, cobalt, and cadmium, as well as nitrate and low pH. We present its draft genome sequence.


Asunto(s)
Actinomycetales/genética , ADN Bacteriano/química , ADN Bacteriano/genética , Genoma Bacteriano , Actinomycetales/efectos de los fármacos , Actinomycetales/aislamiento & purificación , Tolerancia a Medicamentos , Microbiología Ambiental , Concentración de Iones de Hidrógeno , Metales Pesados/toxicidad , Datos de Secuencia Molecular , Nitratos/toxicidad , Análisis de Secuencia de ADN , Tennessee
9.
J Bacteriol ; 194(12): 3290-1, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22628515

RESUMEN

Clostridium thermocellum wild-type strain YS is an anaerobic, thermophilic, cellulolytic bacterium capable of directly converting cellulosic substrates into ethanol. Strain YS and a derived cellulose adhesion-defective mutant strain, AD2, played pivotal roles in describing the original cellulosome concept. We present their draft genome sequences.


Asunto(s)
Clostridium thermocellum/genética , ADN Bacteriano/química , ADN Bacteriano/genética , Genoma Bacteriano , Adhesión Bacteriana , Celulosa/metabolismo , Clostridium thermocellum/metabolismo , Clostridium thermocellum/fisiología , Etanol/metabolismo , Datos de Secuencia Molecular , Mutación , Análisis de Secuencia de ADN
10.
J Bacteriol ; 194(18): 5147-8, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22933770

RESUMEN

Pelosinus fermentans 16S rRNA gene sequences have been reported from diverse geographical sites since the recent isolation of the type strain. We present the genome sequence of the P. fermentans type strain R7 (DSM 17108) and genome sequences for two new strains with different abilities to reduce iron, chromate, and uranium.


Asunto(s)
ADN Bacteriano/química , ADN Bacteriano/genética , Genoma Bacteriano , Análisis de Secuencia de ADN , Veillonellaceae/genética , Cromo/metabolismo , Microbiología Ambiental , Contaminantes Ambientales/metabolismo , Hierro/metabolismo , Datos de Secuencia Molecular , Oxidación-Reducción , Uranio/metabolismo , Veillonellaceae/aislamiento & purificación , Veillonellaceae/metabolismo
11.
Anal Bioanal Chem ; 391(2): 507-14, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18188543

RESUMEN

Escherichia coli O157:H7 remains a continuous public health threat, appearing in meats, water, fruit juices, milk, cheese, and vegetables, where its ingestion at concentrations of perhaps as low as 10 to 100 organisms can result in potent toxin exposure and severe damage to the lining of the intestine. Abdominal pain and diarrhea develop, which in the very young or elderly can progress towards hemolytic uremic syndrome and kidney failure. To assist in the detection of E. coli O157:H7, a recombinant bacteriophage reporter was developed that uses quorum sensing (luxI/luxR) signaling and luxCDABE-based bioluminescent bioreporter sensing to specifically and autonomously respond to O157:H7 serotype E. coli. The bacteriophage reporter, derived from phage PP01, was tested in artificially contaminated foodstuffs including apple juice, tap water, ground beef, and spinach leaf rinsates. In apple juice, detection of E. coli O157:H7 at original inoculums of 1 CFU mL(-1) occurred within approximately 16 h after a 6-h pre-incubation, detection of 1 CFU mL(-1) in tap water occurred within approximately 6.5 h after a 6-h pre-incubation, and detection in spinach leaf rinsates using a real-time Xenogen IVIS imaging system resulted in detection of 1 CFU mL(-1) within approximately 4 h after a 2-h pre-incubation. Detection in ground beef was not successful, however, presumably due to the natural occurrence of quorum sensing autoinducer (N-3-(oxohexanoyl)-L: -homoserine lactone; OHHL), which generated false-positive bioreporter signals in the ground beef samples.


Asunto(s)
Escherichia coli O157/aislamiento & purificación , Contaminación de Alimentos/análisis , Microbiología de Alimentos/métodos , Anciano , Proteínas Bacterianas , Bacteriófago lambda/genética , Bacteriófago lambda/metabolismo , Niño , Escherichia coli O157/genética , Homoserina/análogos & derivados , Humanos , Mediciones Luminiscentes , Percepción de Quorum , Factores de Transcripción/genética
13.
J Food Prot ; 70(6): 1386-92, 2007 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-17612068

RESUMEN

The rapid detection of pathogenic bacteria in food and water is vital for the prevention of foodborne illness. In this study, the lux reporter genes were used in a new bioassay that allows pathogen monitoring without multiple sample manipulations or the addition of exogenous substrate. A recombinant phage specific for Escherichia coli 0157:H7 was constructed that, upon infection, catalyzes the synthesis of N-(3-oxohexanoyl)-L-homoserine lactone (OHHL). This phage PP01 derivative carries the luxI gene from Vibrio fischeri under the control of the phage promoter PL. OHHL produced by infected E. coli 0157:H7 induces bioluminescence in bioreporter cells carrying the V. fischeri lux operon. The ability of phage PP0-luxl to detect several strains of E. coli 0157:H7 was confirmed in a 96-well plate assay. In this assay, luxCDABE bioreporter cells capable of detecting OHHL were mixed with phage PPOI-luxl and E. coli 0157:H7, and luminescence was monitored. Reporter phages induced light in bioreporter cells within I h when exposed to 10(4) CFU/ml of E. coli 0157:H7 and were able to detect 10 CFU/ml in pure culture with a preincubation step (total detection time, 4 h). The detection method was also applied to contaminated apple juice and was able to detect 10(4) CFU/ml of E. coli 0157:H7 in 2 h after a 6-h preincubation.


Asunto(s)
Aliivibrio fischeri/genética , Proteínas Bacterianas/genética , Escherichia coli O157/genética , Contaminación de Alimentos/análisis , Microbiología de Alimentos , Factores de Transcripción/genética , 4-Butirolactona/análogos & derivados , 4-Butirolactona/metabolismo , Bacteriófagos , Recuento de Colonia Microbiana , Escherichia coli O157/virología , Homoserina/análogos & derivados , Humanos , Lactonas , Mediciones Luminiscentes , Operón , Proteínas Recombinantes , Especificidad de la Especie
14.
Int J Trichology ; 9(2): 73-75, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28839392

RESUMEN

Trichoscopy is a noninvasive visualization tool used to more accurately diagnose hair and scalp disorders. Alopecia areata (AA) in the patient of African descent can mimic the early signs of central centrifugal cicatricial alopecia (CCCA), especially if the initial presentation of hair loss occurs on the central scalp. Two African-American women presented with singular round-ovoid patches of decreased hair loss on the central scalp. Given the clinical presentation, CCCA was the working diagnosis. However, using dermoscopy, the patients were found to have exclamation hairs and short broken hairs on a background of honeycomb-like pigmented network and regular pinpoint white dots consistent with AA. The diagnosis was confirmed on biopsy. We demonstrate the role of dermoscopy for diagnosing AA in the patient of African descent.

15.
BMC Syst Biol ; 9: 30, 2015 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-26111937

RESUMEN

BACKGROUND: Thermoanaerobacterium saccharolyticum is a hemicellulose-degrading thermophilic anaerobe that was previously engineered to produce ethanol at high yield. A major project was undertaken to develop this organism into an industrial biocatalyst, but the lack of genome information and resources were recognized early on as a key limitation. RESULTS: Here we present a set of genome-scale resources to enable the systems level investigation and development of this potentially important industrial organism. Resources include a complete genome sequence for strain JW/SL-YS485, a genome-scale reconstruction of metabolism, tiled microarray data showing transcription units, mRNA expression data from 71 different growth conditions or timepoints and GC/MS-based metabolite analysis data from 42 different conditions or timepoints. Growth conditions include hemicellulose hydrolysate, the inhibitors HMF, furfural, diamide, and ethanol, as well as high levels of cellulose, xylose, cellobiose or maltodextrin. The genome consists of a 2.7 Mbp chromosome and a 110 Kbp megaplasmid. An active prophage was also detected, and the expression levels of CRISPR genes were observed to increase in association with those of the phage. Hemicellulose hydrolysate elicited a response of carbohydrate transport and catabolism genes, as well as poorly characterized genes suggesting a redox challenge. In some conditions, a time series of combined transcription and metabolite measurements were made to allow careful study of microbial physiology under process conditions. As a demonstration of the potential utility of the metabolic reconstruction, the OptKnock algorithm was used to predict a set of gene knockouts that maximize growth-coupled ethanol production. The predictions validated intuitive strain designs and matched previous experimental results. CONCLUSION: These data will be a useful asset for efforts to develop T. saccharolyticum for efficient industrial production of biofuels. The resources presented herein may also be useful on a comparative basis for development of other lignocellulose degrading microbes, such as Clostridium thermocellum.


Asunto(s)
Genoma Bacteriano/genética , Genómica/métodos , Thermoanaerobacterium/genética , Secuencia de Bases , Biocombustibles/microbiología , Furaldehído/análogos & derivados , Furaldehído/farmacología , Industrias , Modelos Biológicos , Datos de Secuencia Molecular , Análisis de Secuencia por Matrices de Oligonucleótidos , Polisacáridos/farmacología , Thermoanaerobacterium/efectos de los fármacos , Thermoanaerobacterium/crecimiento & desarrollo , Thermoanaerobacterium/metabolismo
16.
Biotechnol Biofuels ; 6(1): 131, 2013 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-24028713

RESUMEN

BACKGROUND: The thermophilic anaerobe Clostridium thermocellum is a candidate consolidated bioprocessing (CBP) biocatalyst for cellulosic ethanol production. It is capable of both cellulose solubilization and its fermentation to produce lignocellulosic ethanol. Intolerance to stresses routinely encountered during industrial fermentations may hinder the commercial development of this organism. A previous C. thermocellum ethanol stress study showed that the largest transcriptomic response was in genes and proteins related to nitrogen uptake and metabolism. RESULTS: In this study, C. thermocellum was grown to mid-exponential phase and treated with furfural or heat to a final concentration of 3 g.L-1 or 68°C respectively to investigate general and specific physiological and regulatory stress responses. Samples were taken at 10, 30, 60 and 120 min post-shock, and from untreated control fermentations, for transcriptomic analyses and fermentation product determinations and compared to a published dataset from an ethanol stress study. Urea uptake genes were induced following furfural stress, but not to the same extent as ethanol stress and transcription from these genes was largely unaffected by heat stress. The largest transcriptomic response to furfural stress was genes for sulfate transporter subunits and enzymes in the sulfate assimilatory pathway, although these genes were also affected late in the heat and ethanol stress responses. Lactate production was higher in furfural treated culture, although the lactate dehydrogenase gene was not differentially expressed under this condition. Other redox related genes such as a copy of the rex gene, a bifunctional acetaldehyde-CoA/alcohol dehydrogenase and adjacent genes did show lower expression after furfural stress compared to the control, heat and ethanol fermentation profiles. Heat stress induced expression from chaperone related genes and overlap was observed with the responses to the other stresses. This study suggests the involvement of C. thermocellum genes with functions in oxidative stress protection, electron transfer, detoxification, sulfur and nitrogen acquisition, and DNA repair mechanisms in its stress responses and the use of different regulatory networks to coordinate and control adaptation. CONCLUSIONS: This study has identified C. thermocellum gene regulatory motifs and aspects of physiology and gene regulation for further study. The nexus between future systems biology studies and recently developed genetic tools for C. thermocellum offers the potential for more rapid strain development and for broader insights into this organism's physiology and regulation.

17.
Genome Announc ; 1(3)2013 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-23792743

RESUMEN

Saccharomyces cerevisiae strain M3707 was isolated from a sample of commercial distillers yeast, and its genome sequence together with the genome sequences for the four derived haploid strains M3836, M3837, M3838, and M3839 has been determined. Yeasts have potential for consolidated bioprocessing (CBP) for biofuel production, and access to these genome sequences will facilitate their development.

18.
PLoS One ; 8(7): e68886, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23874800

RESUMEN

BACKGROUND: Zymomonas mobilis ZM4 is a capable ethanologenic bacterium with high ethanol productivity and ethanol tolerance. Previous studies indicated that several stress-related proteins and changes in the ZM4 membrane lipid composition may contribute to ethanol tolerance. However, the molecular mechanisms of its ethanol stress response have not been elucidated fully. METHODOLOGY/PRINCIPAL FINDINGS: In this study, ethanol stress responses were investigated using systems biology approaches. Medium supplementation with an initial 47 g/L (6% v/v) ethanol reduced Z. mobilis ZM4 glucose consumption, growth rate and ethanol productivity compared to that of untreated controls. A proteomic analysis of early exponential growth identified about one thousand proteins, or approximately 55% of the predicted ZM4 proteome. Proteins related to metabolism and stress response such as chaperones and key regulators were more abundant in the early ethanol stress condition. Transcriptomic studies indicated that the response of ZM4 to ethanol is dynamic, complex and involves many genes from all the different functional categories. Most down-regulated genes were related to translation and ribosome biogenesis, while the ethanol-upregulated genes were mostly related to cellular processes and metabolism. Transcriptomic data were used to update Z. mobilis ZM4 operon models. Furthermore, correlations among the transcriptomic, proteomic and metabolic data were examined. Among significantly expressed genes or proteins, we observe higher correlation coefficients when fold-change values are higher. CONCLUSIONS: Our study has provided insights into the responses of Z. mobilis to ethanol stress through an integrated "omics" approach for the first time. This systems biology study elucidated key Z. mobilis ZM4 metabolites, genes and proteins that form the foundation of its distinctive physiology and its multifaceted response to ethanol stress.


Asunto(s)
Etanol/farmacología , Biología de Sistemas/métodos , Zymomonas/efectos de los fármacos , Zymomonas/metabolismo , Transcriptoma/efectos de los fármacos
19.
Biotechnol Biofuels ; 6(1): 179, 2013 Dec 02.
Artículo en Inglés | MEDLINE | ID: mdl-24295562

RESUMEN

BACKGROUND: The thermophilic anaerobe Clostridium thermocellum is a candidate consolidated bioprocessing (CBP) biocatalyst for cellulosic ethanol production. The aim of this study was to investigate C. thermocellum genes required to ferment biomass substrates and to conduct a robust comparison of DNA microarray and RNA sequencing (RNA-seq) analytical platforms. RESULTS: C. thermocellum ATCC 27405 fermentations were conducted with a 5 g/L solid substrate loading of either pretreated switchgrass or Populus. Quantitative saccharification and inductively coupled plasma emission spectroscopy (ICP-ES) for elemental analysis revealed composition differences between biomass substrates, which may have influenced growth and transcriptomic profiles. High quality RNA was prepared for C. thermocellum grown on solid substrates and transcriptome profiles were obtained for two time points during active growth (12 hours and 37 hours postinoculation). A comparison of two transcriptomic analytical techniques, microarray and RNA-seq, was performed and the data analyzed for statistical significance. Large expression differences for cellulosomal genes were not observed. We updated gene predictions for the strain and a small novel gene, Cthe_3383, with a putative AgrD peptide quorum sensing function was among the most highly expressed genes. RNA-seq data also supported different small regulatory RNA predictions over others. The DNA microarray gave a greater number (2,351) of significant genes relative to RNA-seq (280 genes when normalized by the kernel density mean of M component (KDMM) method) in an analysis of variance (ANOVA) testing method with a 5% false discovery rate (FDR). When a 2-fold difference in expression threshold was applied, 73 genes were significantly differentially expressed in common between the two techniques. Sulfate and phosphate uptake/utilization genes, along with genes for a putative efflux pump system were some of the most differentially regulated transcripts when profiles for C. thermocellum grown on either pretreated switchgrass or Populus were compared. CONCLUSIONS: Our results suggest that a high degree of agreement in differential gene expression measurements between transcriptomic platforms is possible, but choosing an appropriate normalization regime is essential.

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