RESUMO
Deciphering the mechanisms of bacterial fatty acid biosynthesis is crucial for both the engineering of bacterial hosts to produce fatty acid-derived molecules and the development of new antibiotics. However, gaps in our understanding of the initiation of fatty acid biosynthesis remain. Here, we demonstrate that the industrially relevant microbe Pseudomonas putida KT2440 contains three distinct pathways to initiate fatty acid biosynthesis. The first two routes employ conventional ß-ketoacyl-ACP synthase III enzymes, FabH1 and FabH2, that accept short- and medium-chain-length acyl-CoAs, respectively. The third route utilizes a malonyl-ACP decarboxylase enzyme, MadB. A combination of exhaustive in vivo alanine-scanning mutagenesis, in vitro biochemical characterization, X-ray crystallography, and computational modeling elucidate the presumptive mechanism of malonyl-ACP decarboxylation via MadB. Given that functional homologs of MadB are widespread throughout domain Bacteria, this ubiquitous alternative fatty acid initiation pathway provides new opportunities to target a range of biotechnology and biomedical applications.
Assuntos
3-Oxoacil-(Proteína de Transporte de Acila) Sintase , Pseudomonas putida , Pseudomonas putida/genética , Pseudomonas putida/metabolismo , 3-Oxoacil-(Proteína de Transporte de Acila) Sintase/genética , Mutagênese , Ácidos GraxosRESUMO
BACKGROUND: Surgeons commonly repeat preoperative endoscopy before planned colorectal resections. The reasons for this are not entirely clear, and repeat endoscopy may lead to delays in curative resection, increased costs, and patient discomfort. OBJECTIVE: This study aimed to determine practice patterns, localization techniques, and processes of communication undertaken by endoscopy specialists in a high-volume regional health authority. DESIGN: This was a qualitative study involving standardized, semi-structured, in-depth interviews that were conducted in person. Data were analyzed using a thematic analysis approach. SETTINGS: The study was conducted at Canadian tertiary and community facilities. PARTICIPANTS: Ten general surgeons and 10 gastroenterologists were included using a convenience sampling technique. MAIN OUTCOME MEASURES: Interview questions were developed to understand the perspectives and practice patterns of endoscopists when approaching patients diagnosed with colorectal lesions requiring surgical resection. The decision-making process to perform a repeat preoperative endoscopy was assessed. RESULTS: Three key themes emerged: 1) patterns of communication, 2) feedback, and 3) trust. Thematic analysis revealed that poor communication and ambiguous documentation increased the likelihood of performing repeat preoperative endoscopy. Inconsistencies in tattooing practices and lesion location were important factors. Negative experiences and factors related to interprofessional trust emerged as key contributors to repeat preoperative endoscopy. LIMITATIONS: The transferability of findings to health care systems outside Canada may be limited and requires further study. CONCLUSIONS: Suboptimal endoscopic reporting contributes to gaps in communication among endoscopists. In addition, lack of consistent feedback and mutual trust may increase the likelihood of performing repeat preoperative lower endoscopy. Inconsistent tattooing practices pose significant concerns for accurate intraoperative lesion localization. Establishing collaborative work environments through joint educational initiatives may enhance communication and mitigate unnecessary repeat procedures. These results support the need for standardized guidelines and endoscopic reporting in the management of colorectal lesions. See Video Abstract at http://links.lww.com/DCR/B879 . LA VARIABILIDAD EN LAS PRCTICAS DE COMUNICACIN Y PRESENTACIN DE INFORMES ENTRE GASTROENTERLOGOS Y CIRUJANOS GENERALES CONTRIBUYE A REPETIR LA ENDOSCOPIA PREOPERATORIA PARA LAS NEOPLASIAS COLORRECTALES UN ANLISIS CUALITATIVO: ANTECEDENTES:Los cirujanos suelen repetir la endoscopia preoperatoria antes de las resecciones colorrectales planificadas. Las razones de esto no están del todo claras y la repetición de la endoscopia puede provocar retrasos en la resección curativa, aumento de los costos y malestar del paciente.OBJETIVO:Nuestro objetivo fue determinar patrones de práctica, técnicas de localización y procesos de comunicación realizados por especialistas en endoscopia, en una autoridad sanitaria regional, de alto volumen.DISEÑO:Este fue un estudio cualitativo, que involucró entrevistas estandarizadas, semiestructuradas y en profundidad que se llevaron a cabo en persona. Los datos se analizaron mediante un enfoque de análisis temático.ENTORNO CLINICO:El estudio se llevó a cabo en instalaciones comunitarias y terciarias canadienses.PARTICIPANTES:Se incluyeron 10 cirujanos generales y 10 gastroenterólogos, utilizando una técnica de muestreo por conveniencia.PRINCIPALES MEDIDAS DE VALORACION:Las preguntas de la entrevista se desarrollaron para comprender las perspectivas y los patrones de práctica de los endoscopistas, cuando se acercan a pacientes diagnosticados con lesiones colorrectales que requieren resección quirúrgica. Se evaluó el proceso de toma de decisiones para realizar una nueva endoscopia preoperatoria.RESULTADOS:Surgieron tres temas clave: 1) patrones de comunicación, 2) retroalimentación y 3) confianza. El análisis temático reveló que la pobre comunicación y la ambigua documentación aumentaron la probabilidad de realizar una nueva endoscopia preoperatoria. Las inconsistencias en las prácticas de tatuaje y la ubicación de las lesiones fueron factores importantes. Las experiencias pasadas negativas y los factores relacionados con la confianza interprofesional surgieron como contribuyentes clave para repetir la endoscopia preoperatoria.LIMITACIONES:La transferibilidad de los hallazgos a los sistemas de atención médica fuera de Canadá, puede ser limitada y requiere más estudios.CONCLUSIONES:Los informes endoscópicos subóptimos contribuyen a las brechas en la comunicación entre los endoscopistas. Además, la falta de retroalimentación consistente y la confianza mutua pueden aumentar la probabilidad de realizar una nueva endoscopia baja preoperatoria. Las prácticas inconsistentes de tatuaje, plantean preocupaciones importantes para la localización precisa de las lesiones intraoperatorias. El establecimiento de entornos de trabajo colaborativo a través de iniciativas educativas conjuntas pueden mejorar la comunicación y mitigar la repetición de procedimientos innecesarios. Estos resultados apoyan la necesidad de pautas estandarizadas e informes endoscópicos en el tratamiento de las lesiones colorrectales. Consulte Video Resumen en http://links.lww.com/DCR/B879 . (Traducción-Dr. Fidel Ruiz Healy ).
Assuntos
Neoplasias Colorretais , Gastroenterologistas , Cirurgiões , Humanos , Estudos Retrospectivos , Canadá , Neoplasias Colorretais/cirurgia , Neoplasias Colorretais/patologia , Endoscopia Gastrointestinal , ComunicaçãoRESUMO
Bacterial gene expression is orchestrated by numerous transcription factors (TFs). Elucidating how gene expression is regulated is fundamental to understanding bacterial physiology and engineering it for practical use. In this study, a machine-learning approach was applied to uncover the genome-scale transcriptional regulatory network (TRN) in Pseudomonas putida KT2440, an important organism for bioproduction. We performed independent component analysis of a compendium of 321 high-quality gene expression profiles, which were previously published or newly generated in this study. We identified 84 groups of independently modulated genes (iModulons) that explain 75.7% of the total variance in the compendium. With these iModulons, we (i) expand our understanding of the regulatory functions of 39 iModulon associated TFs (e.g., HexR, Zur) by systematic comparison with 1993 previously reported TF-gene interactions; (ii) outline transcriptional changes after the transition from the exponential growth to stationary phases; (iii) capture group of genes required for utilizing diverse carbon sources and increased stationary response with slower growth rates; (iv) unveil multiple evolutionary strategies of transcriptome reallocation to achieve fast growth rates; and (v) define an osmotic stimulon, which includes the Type VI secretion system, as coordination of multiple iModulon activity changes. Taken together, this study provides the first quantitative genome-scale TRN for P. putida KT2440 and a basis for a comprehensive understanding of its complex transcriptome changes in a variety of physiological states.
Assuntos
Pseudomonas putida , Regulação Bacteriana da Expressão Gênica , Redes Reguladoras de Genes , Aprendizado de Máquina , Pseudomonas putida/genética , Pseudomonas putida/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , TranscriptomaRESUMO
Photoreceptors are highly compartmentalized cells with large amounts of proteins synthesized in the inner segment (IS) and transported to the outer segment (OS) and synaptic terminal. Tulp1 is a photoreceptor-specific protein localized to the IS and synapse. In the absence of Tulp1, several OS-specific proteins are mislocalized and synaptic vesicle recycling is impaired. To better understand the involvement of Tulp1 in protein trafficking, our approach in the current study was to physically isolate Tulp1-containing photoreceptor compartments by serial tangential sectioning of retinas and to identify compartment-specific Tulp1 binding partners by immunoprecipitation followed by liquid chromatography tandem mass spectrometry. Our results indicate that Tulp1 has two distinct interactomes. We report the identification of: (1) an IS-specific interaction between Tulp1 and the motor protein Kinesin family member 3a (Kif3a), (2) a synaptic-specific interaction between Tulp1 and the scaffold protein Ribeye, and (3) an interaction between Tulp1 and the cytoskeletal protein microtubule-associated protein 1B (MAP1B) in both compartments. Immunolocalization studies in the wild-type retina indicate that Tulp1 and its binding partners co-localize to their respective compartments. Our observations are compatible with Tulp1 functioning in protein trafficking in multiple photoreceptor compartments, likely as an adapter molecule linking vesicles to molecular motors and the cytoskeletal scaffold.
Assuntos
Oxirredutases do Álcool/metabolismo , Proteínas Correpressoras/metabolismo , Proteínas do Olho/metabolismo , Cinesinas/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Células Fotorreceptoras de Vertebrados/metabolismo , Transporte Proteico , Animais , Cromatografia Líquida , Cílios , Proteínas do Olho/genética , Imunoprecipitação , Camundongos , Camundongos Knockout , Ligação Proteica , Proteômica , Ratos , Sinapses , Espectrometria de Massas em TandemRESUMO
Self-regulation strategies of selection, optimization, and compensation (SR-SOC) have been found to predict arthritis self-efficacy and quality of life among community-dwelling people aging with arthritis and multimorbidity. The current study aimed to describe the health resources and chronic disabling symptom characteristics of community-dwelling people aging with arthritis and multimorbidity and investigate how these characteristics influence and predict SR-SOC strategies in managing arthritis multimorbidity after controlling for demographics and comorbidities. One hundred forty individuals aged >50 years completed surveys on demographics, comorbidities, health resources, symptoms, and SR-SOC strategy use frequencies. Descriptive statistics were used to describe sample characteristics. Correlations and multivariate hierarchical stepwise regressions were used to examine the associated characteristics and predictors for SR-SOC strategy use frequency. Lower health literacy, health care provider communication quality, and smaller social network were reported less often than arthritis in general. Significant predictors of SR-SOC strategy use were physical symptoms, health care provider communication quality, and age (p < 0.05). Better symptom management and health care provider communication quality could help promote self-regulation. [Journal of Gerontological Nursing, 47(1), 35-45.].
Assuntos
Artrite , Autocontrole , Envelhecimento , Humanos , Vida Independente , Multimorbidade , Qualidade de VidaRESUMO
Pseudomonas putida KT2440 has received increasing attention as an important biocatalyst for the conversion of diverse carbon sources to multiple products, including the olefinic diacid, cis,cis-muconic acid (muconate). P. putida has been previously engineered to produce muconate from glucose; however, periplasmic oxidation of glucose causes substantial 2-ketogluconate accumulation, reducing product yield and selectivity. Deletion of the glucose dehydrogenase gene (gcd) prevents 2-ketogluconate accumulation, but dramatically slows growth and muconate production. In this work, we employed adaptive laboratory evolution to improve muconate production in strains incapable of producing 2-ketogluconate. Growth-based selection improved growth, but reduced muconate titer. A new muconate-responsive biosensor was therefore developed to enable muconate-based screening using fluorescence activated cell sorting. Sorted clones demonstrated both improved growth and muconate production. Mutations identified by whole genome resequencing of these isolates indicated that glucose metabolism may be dysregulated in strains lacking gcd. Using this information, we used targeted engineering to recapitulate improvements achieved by evolution. Deletion of the transcriptional repressor gene hexR improved strain growth and increased the muconate production rate, and the impact of this deletion was investigated using transcriptomics. The genes gntZ and gacS were also disrupted in several evolved clones, and deletion of these genes further improved strain growth and muconate production. Together, these targets provide a suite of modifications that improve glucose conversion to muconate by P. putida in the context of gcd deletion. Prior to this work, our engineered strain lacking gcd generated 7.0 g/L muconate at a productivity of 0.07 g/L/h and a 38% yield (mol/mol) in a fed-batch bioreactor. Here, the resulting strain with the deletion of hexR, gntZ, and gacS achieved 22.0 g/L at 0.21 g/L/h and a 35.6% yield (mol/mol) from glucose in similar conditions. These strategies enabled enhanced muconic acid production and may also improve production of other target molecules from glucose in P. putida.
Assuntos
Glucose/metabolismo , Engenharia Metabólica , Pseudomonas putida , Ácido Sórbico/análogos & derivados , Pseudomonas putida/genética , Pseudomonas putida/metabolismo , Ácido Sórbico/metabolismoRESUMO
Despite multiple national initiatives to improve quality of life in nursing home (NH) residents with dementia, inefficiencies still exist regarding inappropriate psychotropic medication use to manage communication of distress. The goals of the current article are to: (a) create a person-centered care plan/process for NH community staff to manage challenging dementia behaviors; (b) provide guidelines for geriatric practitioners (GPs) to decrease psychotropic medication use in residents with dementia; (c) discuss organizational culture and its relationship to the management of non-cognitive neuropsychiatric symptoms (NPS) of dementia; and (d) emphasize nonpharmacological approaches as first-line treatment of NPS in NH residents with dementia. [Journal of Gerontological Nursing, 46(2), 9-17.].
Assuntos
Demência/tratamento farmacológico , Demência/psicologia , Casas de Saúde , Planejamento de Assistência ao Paciente , Padrões de Prática Médica , Psicotrópicos/uso terapêutico , Idoso , Feminino , Humanos , MasculinoRESUMO
INTRODUCTION: Central venous access devices (CVADs) facilitate repeated or urgent treatments for paediatric haemophilia patients, but are associated with complications. This study examined the burden of illness, healthcare utilization and costs for CVADs in a real-world hospital setting. MATERIALS AND METHODS: This study included haemophilia patients ages ≤18 years with discharges during 2006-2014 in the US Premier Healthcare Database. Haemophilia was identified using ICD-9 diagnosis codes and CVAD exposure using billing information. After matching haemophilia patients with and without CVADs on demographic and clinical characteristics, we compared infection, thrombosis, length of stay (LOS), inflation-adjusted hospital cost (2014 $USD) and readmission outcomes using generalized estimating equation models adjusted for hospital teaching status. RESULTS: Among 4793 paediatric haemophilia patients treated at one of 548 hospitals, a total of 197 patients were identified with CVAD exposure. The matched sample included 310 haemophilia patients (155 CVAD and 155 non-CVAD). CVAD cases had greater frequencies of all-cause infections (29% vs 17%, P = .01) and thrombosis (6% vs 1%, P = .06), longer adjusted mean LOS (9.5 vs 4.7 days, P = .002), higher adjusted mean inpatient total hospitalization costs ($47200 vs $25389, P = .02) as well as more inpatient and outpatient visits at 30-, 60- and 90-days (P < .05 for all differences) compared with non-CVAD patients. CONCLUSION: Paediatric haemophilia patients with CVADs experienced greater infection rates, healthcare utilization and higher hospitalization costs compared with non-CVAD patients. The results of this study may inform further research efforts to understand the costs and benefits of novel treatment alternatives for young haemophilia patients requiring CVADs.
Assuntos
Cateteres Venosos Centrais , Efeitos Psicossociais da Doença , Acessibilidade aos Serviços de Saúde/estatística & dados numéricos , Hemofilia A/economia , Hemofilia A/terapia , Hospitais , Adolescente , Criança , Pré-Escolar , Feminino , Hemofilia A/complicações , Humanos , Lactente , Recém-Nascido , Infecções/complicações , Tempo de Internação , Masculino , Pacientes Ambulatoriais , Estudos Retrospectivos , Trombose/complicações , Estados UnidosRESUMO
This study outlines a new method of automatically estimating weed species and growth stages (from cotyledon until eight leaves are visible) of in situ images covering 18 weed species or families. Images of weeds growing within a variety of crops were gathered across variable environmental conditions with regards to soil types, resolution and light settings. Then, 9649 of these images were used for training the computer, which automatically divided the weeds into nine growth classes. The performance of this proposed convolutional neural network approach was evaluated on a further set of 2516 images, which also varied in term of crop, soil type, image resolution and light conditions. The overall performance of this approach achieved a maximum accuracy of 78% for identifying Polygonum spp. and a minimum accuracy of 46% for blackgrass. In addition, it achieved an average 70% accuracy rate in estimating the number of leaves and 96% accuracy when accepting a deviation of two leaves. These results show that this new method of using deep convolutional neural networks has a relatively high ability to estimate early growth stages across a wide variety of weed species.
Assuntos
Redes Neurais de Computação , Poaceae/crescimento & desenvolvimento , Polygonum/crescimento & desenvolvimento , Processamento de Imagem Assistida por Computador , Folhas de Planta/anatomia & histologia , Folhas de Planta/fisiologia , Poaceae/anatomia & histologia , Poaceae/fisiologia , Polygonum/anatomia & histologia , Polygonum/fisiologiaRESUMO
Branched-chain fatty acids (BCFAs) are key precursors of branched-chain fuels, which have cold-flow properties superior to straight chain fuels. BCFA production in Gram-negative bacterial hosts is inherently challenging because it competes directly with essential and efficient straight-chain fatty acid (SCFA) biosynthesis. Previously, Escherichia coli strains engineered for BCFA production also co-produced a large percentage of SCFA, complicating efficient isolation of BCFA. Here, we identified a key bottleneck in BCFA production: incomplete lipoylation of 2-oxoacid dehydrogenases. We engineered two protein lipoylation pathways that not only restored 2-oxoacid dehydrogenase lipoylation, but also increased BCFA production dramatically. E. coli expressing an optimized lipoylation pathway produced 276mg/L BCFA, comprising 85% of the total free fatty acids (FFAs). Furthermore, we fine-tuned BCFA branch positions, yielding strains specifically producing ante-iso or odd-chain iso BCFA as 77% of total FFA, separately. When coupled with an engineered branched-chain amino acid pathway to enrich the branched-chain α-ketoacid pool, BCFA can be produced from glucose at 181mg/L and 72% of total FFA. While E. coli can metabolize BCFAs, we demonstrated that they are not incorporated into the cell membrane, allowing our system to produce a high percentage of BCFA without affecting membrane fluidity. Overall, this work establishes a platform for high percentage BCFA production, providing the basis for efficient and specific production of a variety of branched-chain hydrocarbons in engineered bacterial hosts.
Assuntos
Proteínas de Escherichia coli/metabolismo , Escherichia coli/fisiologia , Ácidos Graxos/biossíntese , Glucose/metabolismo , Engenharia Metabólica/métodos , Redes e Vias Metabólicas/fisiologia , Oxirredutases/genética , Vias Biossintéticas/fisiologia , Proteínas de Escherichia coli/genética , Ácidos Graxos/genética , Melhoramento Genético/métodos , Lipogênese/fisiologia , Oxirredutases/metabolismoRESUMO
Interest has recently reawakened in whether loss of the heterochromatic X chromosome (Barr body) is prevalent in certain breast and ovarian cancers, and new insights into the mechanisms involved have emerged. Mitotic segregation errors commonly explain the loss of the inactive X chromosome (Xi), but compromise of Xi heterochromatin in some cancers may signal broader deficits of nuclear heterochromatin. The debated link between BRCA1 and Xi might reflect a general relationship between BRCA1 and heterochromatin, which could connect BRCA1 to both epigenetic and genetic instability. We suggest that heterochromatic instability is a common but largely unexplored mechanism, leading to widespread genomic misregulation and the evolution of some cancers.
Assuntos
Neoplasias da Mama/patologia , Neoplasias Ovarianas/patologia , Cromatina Sexual/patologia , Neoplasias da Mama/metabolismo , Cromossomos Humanos X , Feminino , Genes BRCA1 , Heterocromatina/metabolismo , Humanos , Neoplasias Ovarianas/metabolismo , Cromatina Sexual/metabolismoRESUMO
Photoreceptors (PRs) are highly polarized and compartmentalized cells with large amounts of proteins synthesized in the inner segment (IS) and transported to the outer segment (OS) and synaptic terminal. The PR-specific protein, Tulp1, is localized to the IS and synapse and is hypothesized to be involved in protein trafficking. To better understand the molecular processes that regulate protein trafficking in PRs, we aimed to identify compartment-specific Tulp1 binding partners. Serial tangential sectioning of Long Evans rat retinas was utilized to isolate the IS and synaptic PR compartments. Tulp1 binding partners in each of these layers were identified using co-immunoprecipitation (co-IP) with Tulp1 antibodies. The co-IP eluates were separated by SDS-PAGE, trypsinized into peptide fragments, and proteins were identified by liquid chromatography tandem mass spectrometry. In the IS, potential Tulp1-binding partners included cytoskeletal scaffold proteins, protein trafficking molecules, as well as members of the phototransduction cascade. In the synaptic region, the majority of interacting proteins identified were cytoskeletal. A separate subset of proteins were identified in both the IS and synapse including chaperones and family members of the GTPase activating proteins. Tulp1 has two distinct PR compartment-specific interactomes. Our results support the hypothesis that Tulp1 is involved in the trafficking of proteins from the IS to the OS and the continuous membrane remodeling and vesicle cycling at the synaptic terminal.
Assuntos
Proteínas de Transporte/metabolismo , Proteínas do Olho/metabolismo , Células Fotorreceptoras de Vertebrados/metabolismo , Segmento Interno das Células Fotorreceptoras da Retina/metabolismo , Animais , Anticorpos/imunologia , Anticorpos/metabolismo , Cromatografia Líquida , Eletroforese em Gel de Poliacrilamida , Proteínas do Olho/genética , Proteínas do Olho/imunologia , Imunoprecipitação , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ligação Proteica , Transporte Proteico , Ratos Long-Evans , Segmento Externo das Células Fotorreceptoras da Retina/metabolismo , Sinapses/metabolismo , Espectrometria de Massas em TandemRESUMO
This manuscript describes a collaborative, seamless program between a community college and a university college of nursing designed to increase the number of nurses prepared with a baccalaureate degree. The three-year Integrated Nursing Pathway provides community college students with a non-nursing associate degree, early introduction to nursing, and seamless progression through BSN education. The model includes dual admission and advising and is driven by the need for collaboration with community colleges, the need to increase the percentage of racial-ethnic minority students, the shortage of faculty, and employer preferences for BSN graduates.
Assuntos
Escolha da Profissão , Comportamento Cooperativo , Bacharelado em Enfermagem/tendências , Modelos Educacionais , Colorado , Currículo , Difusão de Inovações , Humanos , Relações Interinstitucionais , Pesquisa em Educação em Enfermagem , Objetivos Organizacionais , Desenvolvimento de Programas , Avaliação de Programas e Projetos de Saúde , Escolas de Enfermagem/organização & administração , Universidades/organização & administraçãoRESUMO
BACKGROUND: The inclusion of community members and other stakeholders in the establishment of research priorities is vital to ensuring that priorities are congruent with the main concerns of affected communities. PURPOSE: The purpose of this project was to identify priority research topics for addressing the activity and community participation needs of people living with human immunodeficiency virus (HIV) and meaningfully involve multiple stakeholders in the development of those priorities. METHOD: We invited people living with HIV, researchers, service providers, and policy makers to a 2-day forum. Twenty-six people participated in developing priorities through the application of two methodologies, the World Café and Dotmocracy. We evaluated the forum though immediate dialogue and a postproject survey. FINDINGS: Participants identified 10 high-priority research topics. Evaluation findings highlighted positive substantive, instrumental, personal, and normative outcomes of stakeholder involvement. IMPLICATIONS: The identified priority topics can guide future occupational therapy practice and research in this emerging area.
Assuntos
Participação da Comunidade , Comportamento Cooperativo , Infecções por HIV/reabilitação , Pesquisa de Reabilitação , Pesquisa , Humanos , Pesquisa Qualitativa , Inquéritos e QuestionáriosRESUMO
Branched-chain fatty acids (BCFAs) are important precursors for the production of advanced biofuels with improved cold-flow properties. Previous efforts in engineering type II fatty acid synthase (FAS) for BCFA production suffered from low titers and/or the co-production of a large amount of straight-chain fatty acids (SCFAs), making it nearly impossible for further conversion of BCFAs to branched biofuels. Synthesis of both SCFAs and BCFAs requires FabH, the only ß-ketoacyl-(acyl-carrier-protein) synthase in Escherichia coli that catalyzes the initial condensation reaction between malonyl-ACP and a short-chain acyl-CoA. In this study, we demonstrated that replacement of the acetyl-CoA-specific E. coli FabH with a branched-chain-acyl-CoA-specific FabH directed the flux to the synthesis of BCFAs, resulting in a significant enhancement in BCFA titer compared to a strain containing both acetyl-CoA- and branched-chain-acyl-CoA-specific FabHs. We further demonstrated that the composition of BCFAs can be tuned by engineering the upstream pathway to control the supply of different branched-chain acyl-CoAs, leading to the production either even-chain-iso-, odd-chain-iso-, or odd-chain-anteiso-BCFAs separately. Overall, the top-performing strain from this study produced BCFAs at 126 mg/L, comprising 52% of the total free fatty acids.
Assuntos
Acetiltransferases/metabolismo , Proteínas de Escherichia coli/metabolismo , Escherichia coli/enzimologia , Escherichia coli/metabolismo , Ácidos Graxos/biossíntese , Engenharia Metabólica/métodos , 3-Oxoacil-(Proteína de Transporte de Acila) Sintase , Acetiltransferases/genética , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Ácido Graxo Sintase Tipo II/genética , Ácido Graxo Sintase Tipo II/metabolismo , Redes e Vias Metabólicas/genéticaRESUMO
To evaluate the retinal histopathology in donor eyes from patients with autosomal recessive retinitis pigmentosa (arRP) caused by EYS mutations. Eyes from a 72-year-old female (donor 1, family 1), a 91-year-old female (donor 2, family 2), and her 97-year-old sister (donor 3, family 2) were evaluated with macroscopic, scanning laser ophthalmoscopy (SLO) and optical coherence tomography (OCT) imaging. Age-similar normal eyes and an eye donated by donor 1's asymptomatic mother (donor 4, family 1) were used as controls. The perifovea and peripheral retina were processed for microscopy and immunocytochemistry with markers for cone and rod photoreceptor cells. DNA analysis revealed EYS mutations c.2259 + 1G > A and c.2620C > T (p.Q874X) in family 1, and c.4350_4356del (p.I1451Pfs*3) and c.2739-?_3244 + ?del in family 2. Imaging studies revealed the presence of bone spicule pigment in arRP donor retinas. Histology of all three affected donor eyes showed very thin retinas with little evidence of stratified nuclear layers in the periphery. In contrast, the perifovea displayed a prominent inner nuclear layer. Immunocytochemistry analysis demonstrated advanced retinal degenerative changes in all eyes, with near-total absence of rod photoreceptors. In addition, we found that the perifoveal cones were more preserved in retinas from the donor with the midsize genomic rearrangement (c.4350_4356del (p.I1451Pfs*3) and c.2739-?_3244 + ?del) than in retinas from the donors with the truncating (c.2259 + 1G > A and c.2620C > T (p.Q874X) mutations. Advanced retinal degenerative changes with near-total absence of rods and preservation of some perifoveal cones are observed in arRP donor retinas with EYS mutations.
Assuntos
Proteínas do Olho/genética , Mutação , Retinose Pigmentar/genética , Retinose Pigmentar/patologia , Idoso , Idoso de 80 Anos ou mais , Análise Mutacional de DNA , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Hibridização de Ácido Nucleico , Oftalmoscopia , Linhagem , Reação em Cadeia da Polimerase , Doadores de Tecidos , Tomografia de Coerência ÓpticaRESUMO
PURPOSE: To evaluate the histopathology in donor eyes from patients with autosomal dominant retinitis pigmentosa (ADRP) caused by p.P23H, p.P347T and p.P347L rhodopsin ( RHO ) gene mutations. METHODS: Eyes from a 72-year-old male (donor 1), an 83-year-old female (donor 2), an 80-year-old female (donor 3), and three age-similar normal eyes were examined macroscopically, by scanning laser ophthalmoscopy and optical coherence tomography imaging. Perifoveal and peripheral pieces were processed for microscopy and immunocytochemistry with markers for photoreceptor cells. RESULTS: DNA analysis revealed RHO mutations c.68C>A (p.P23H) in donor 1, c.1040C>T (p.P347L) in donor 2 and c.1039C>A (p.P347T) in donor 3. Histology of the ADRP eyes showed retinas with little evidence of stratified nuclear layers in the periphery and a prominent inner nuclear layer present in the perifoveal region in the p.P23H and p.P347T eyes, while it was severely atrophic in the p.P347L eye. The p.P23H and p.P347T mutations cause a profound loss of rods in both the periphery and perifovea, while the p.P347L mutation displays near complete absence of rods in both regions. All three rhodopsin mutations caused a profound loss of cones in the periphery. The p.P23H and p.P347T mutations led to the presence of highly disorganized cones in the perifovea. However, the p.P347L mutation led to near complete absence of cones also in the perifovea. CONCLUSIONS: Our results support clinical findings indicating that mutations affecting residue P347 develop more severe phenotypes than those affecting P23. Furthermore, our results indicate a more severe phenotype in the p.P347L retina as compared to the p.P347T retina.
Assuntos
Mutação Puntual , Células Fotorreceptoras Retinianas Cones/patologia , Células Fotorreceptoras Retinianas Bastonetes/patologia , Retinose Pigmentar/genética , Retinose Pigmentar/patologia , Rodopsina/genética , Idoso , Idoso de 80 Anos ou mais , Arrestina/metabolismo , Eletrorretinografia , Feminino , Humanos , Imuno-Histoquímica , Masculino , Oftalmoscopia , Linhagem , Células Fotorreceptoras Retinianas Cones/metabolismo , Células Fotorreceptoras Retinianas Bastonetes/metabolismo , Rodopsina/metabolismo , Opsinas de Bastonetes/metabolismo , Doadores de Tecidos , Tomografia de Coerência ÓpticaRESUMO
The timing, geographical locations, causes, and consequences of crop domestication have long been major concerns of archaeologists, and agricultural origins and dispersals are currently more relevant than ever to scientists seeking solutions to elusive problems involving food insecurity and global health disparities. Perennial research issues that archaeologists continue to tackle include (1) thinking outside centers of origin that were based on limited and insufficient past knowledge; (2) distinguishing between single and multiple domestications of specific crops; (3) measuring the pace of domestication; and (4) decoupling domestication from agricultural economies. Paleoethnobotanists have expanded their toolkits to include analysis of ancient and modern DNA and have added increasingly sophisticated techniques in the field and the laboratory to derive precise chronological sequences to assess morphological changes in ancient and often fragmentary archaeobotanical remains and to correctly interpret taphonomy and context. Multiple lines of archaeological evidence are ideally brought together, and whenever possible, these are integrated with information from complementary sources. We discuss current perspectives and anthropological approaches to research that have as their goals the fuller and broader understanding of ancient farming societies, the plants that were domesticated, the landscapes that were created, and the culinary legacies that were passed on.
Assuntos
Agricultura , Arqueologia , Evolução Biológica , Produtos Agrícolas/genética , Antropologia , DNA de Plantas , Abastecimento de Alimentos , HumanosRESUMO
Tubby-like protein-1 (Tulp1) is a photoreceptor-specific protein involved in the transport of specific proteins from the inner segment (IS) to the outer segment (OS) in photoreceptor cells. Mutations in the human TULP1 gene cause an early onset form of retinitis pigmentosa. Our previous work has shown an association between Tulp1 and the microtubule-associated protein, MAP1B. An allele of Mtap1a, which encodes the MAP1A protein, significantly delays photoreceptor degeneration in Tulp1 mutant mice. MAP1 proteins are important in stabilizing microtubules in neuronal cells, but their role in photoreceptors remains obscure. To investigate the relationship between Tulp1 and MAP1 proteins, we performed western blots, immunoprecipitations (IP), immunohistochemistry and proximity ligand assays (PLA) in wild-type and tulp1-/- mouse retinas. Our IP experiments provide evidence that Tulp1 and MAP1B interact while PLA experiments localize their interaction to the outer nuclear layer and IS of photoreceptors. Although MAP1A and MAP1B protein levels are not affected in the tulp1-/- retina, they are no longer localized to the OS of photoreceptors. This may be the cause for disorganized OSs in tulp1-/- mice, and indicate that their transport to the OS is Tulp1-dependent.