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1.
Saudi Dent J ; 36(4): 621-626, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38690393

RESUMEN

Background: The aim was to quantify the time elapsed between tooth reconstruction and the end of endodontic treatment, and to assess differences according to sex, age, and tooth group. Material and Methods: A retrospective study was conducted with patient clinical records. Data relating to patient characteristics, treated teeth, endodontic treatment, and subsequent restorative treatment were recorded. Results: For this study, 355 endodontically treated teeth by undergraduate students during 2019 were included. 24 teeth (6.76 %) were not restored, more direct (86.4 %) than indirect (13.6 %) restorations were performed, and the most frequent type of restoration was complex filling. The mean elapsed time from endodontic completion to direct restoration was 7 days, with a minimum of 0 and a maximum of 90 days. For indirect restorations the mean elapsed time was 21 days. Conclusions: The median elapsed time for endodontic tooth reconstruction was 7 days (IQR = 7), however, treatment should not be considered completed until the tooth has been properly restored. In cases where an indirect restoration was also necessary, the median elapsed time was higher (21 days; IQR = 31.5).

2.
Eur J Dent Educ ; 27(4): 1109-1116, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36970773

RESUMEN

INTRODUCTION: The dentist should be able to carry out systematic oral examinations of the mucosa of patients in order to diagnose any alterations at an early stage. MATERIALS AND METHODS: An observational, analytical, prospective, and longitudinal study was carried out. 161 students were evaluated at the beginning of their clinical practice in their 4th year of dental school (September 2019), at the beginning and at the end of their 5th year of dental school (June 2021). Thirty oral lesions were projected, and the students were asked to provide an answer; if the lesions were benign, malignant, or potentially malignant, whether they should be biopsied and/or treated and a presumptive diagnosis. RESULTS: Significant improvement (p < .001) was obtained between the 2019 and 2021 results, in relation to the classification, need for biopsy and treatment of lesions. For differential diagnosis, no significant difference (p = .985) was obtained between the 2019 and 2021 responses. Malignant lesions and PMD obtained mixed results, with the best results corresponding to OSCC. DISCUSSION: In this study, a correct lesion classification by the students was over 50%. As for the OSCC, the results were superior to the rest of the images, reaching more than 95% correct. CONCLUSION: Theoretical-practical training from universities and continuing education for graduates in relation to oral mucosal pathologies should be further promoted.


Asunto(s)
Educación en Odontología , Estudiantes de Odontología , Humanos , Estudios Longitudinales , Estudios Prospectivos , Educación Continua , Encuestas y Cuestionarios
3.
Nat Chem Biol ; 19(6): 671-672, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36894720
4.
Int Urogynecol J ; 31(11): 2367-2375, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32405659

RESUMEN

OBJECTIVE: To assess the association between superficial perineal muscle trauma and perineal pain and dyspareunia. MATERIALS AND METHODS: Prospective cohort study of 405 women with a spontaneous vaginal birth comparing an intact perineum and first-degree perineal trauma group (n = 205) with a second-degree perineal trauma and episiotomy group (n = 200). Perineal pain was measured at 2 days, 10 days, 7 weeks, 3 months and 6 months postpartum. Dyspareunia was assessed at 7 weeks, 3 months and 6 months postpartum. RESULTS: All second-degree perineal traumas and episiotomies involved damage to the bulbospongiosus muscle (BSM), but not always to the superficial transverse perineal muscle (STPM). In case of second-degree trauma or episiotomy, the odds of pain at 10 days and dyspareunia at 6 months postpartum were four- and five-fold greater, respectively, than if the perineum had remained intact or suffered a first-degree perineal trauma [OR 4.4 (95% CI: 2.8-6.9) and OR 5.5 (95% CI: 2.8-10.9), respectively]. When comparing injuries where > 50% BSM ± STPM against those with < 50% BSM torn, pain was significantly higher at 10 days postpartum [OR 1.9 (95% CI: 1.1-3.6], with no difference at 7 weeks, while dyspareunia was significantly higher at 6 months postpartum [OR 3.3 (95% CI: 1.4-7.8)]. There was no difference in perineal pain or dyspareunia when comparing first-degree with < 50% BSM traumas. CONCLUSION: When perineal muscle trauma encompasses > 50% BSM ± STPM, perineal pain and dyspareunia persisted until 10 days and 6 months postpartum, respectively.


Asunto(s)
Dispareunia , Perineo , Estudios de Cohortes , Dispareunia/etiología , Episiotomía/efectos adversos , Femenino , Humanos , Músculos , Periodo Posparto , Embarazo , Estudios Prospectivos
5.
Endodoncia (Madr.) ; 37(3): 32-36, dic. 2019. ilus
Artículo en Español | IBECS | ID: ibc-189960

RESUMEN

Introducción: La Reabsorción Cervical Invasiva (RCI) se origina en la superficie externa de la raíz, generalmente por un daño previo, y quizá crónico, del ligamento periodontal, y una rotura de la capa de tejido no mineralizado que permite una actividad odontoclástica, invadiendo la dentina en cualquier dirección y con diferentes grados. Dejada a su libre evolución conlleva la pérdida del diente. Caso clínico: Paciente de 45 años que acude a la consulta por presentar un tracto sinusal a nivel del 4.7. Se diagnostica necrosis pulpar con absceso apical crónico de etiología dudosa. Tras el fracaso del tratamiento de conductos, se opta por la exodoncia y se realiza el diagnóstico intraoperatorio de RCI. Tratada la causa, se realiza el reimplante intencional (RI). Conclusión: La técnica de RI se presenta como una alternativa a la cirugía periradicular, siendo una herramienta valiosa en la conservación de dientes con pronóstico comprometido


No disponible


Asunto(s)
Humanos , Femenino , Persona de Mediana Edad , Resorción Dentaria/cirugía , Resorción Dentaria/diagnóstico por imagen , Cuello del Diente/diagnóstico por imagen , Cuello del Diente/cirugía , Resultado del Tratamiento , Estudios de Seguimiento
6.
Cient. dent. (Ed. impr.) ; 16(1): 47-54, ene.-abr. 2019. graf, tab
Artículo en Español | IBECS | ID: ibc-183381

RESUMEN

Cuando se combinan entre sí, las células madre, las matrices y los factores de crecimiento tienen la capacidad de regenerar un tejido, tal como el complejo dentino-pulpar. La ingeniería tisular está adquiriendo cada vez más importancia en el campo de la endodoncia como una alternativa a la obturación clásica con gutapercha. El objetivo de esta revisión es comparar los diferentes materiales que actuarían como matrices disponibles en la actualidad, así como conocer el alcance del conocimiento sobre los factores de crecimiento relacionados con la regeneración de la pulpa, señalando las principales limitaciones y elaborando un protocolo para futuros procedimientos regenerativos. Las matrices de colágeno han demostrado ser una opción óptima, ya que son biodegradables, pueden ser autólogos y existe una alta disposición. El factor de crecimiento insulínico tipo 1 y el factor de crecimiento derivado de plaquetas han demostrado estar implicados en la proliferación celular. El factor de crecimiento endotelial vascular es uno de los más importantes para la proliferación de la red vascular. El aislamiento celular y los altos costos son los principales obstáculos. La combinación de un andamio de colágeno, factor de crecimiento insulínico tipo 1, factor de crecimiento derivado de plaquetas, factor de crecimiento endotelial vascular y células madre de tejido pulpar de dientes deciduos (SHEDs) podría dar buenos resultados en la regeneración de la pulpa dental


When combined together, stem cells, scaffolds and growth factors have the ability of regenerating a whole tissue, for example the dental-pulp complex. Tissue engineering is getting more and more importance in the endodontic field as an alternative to the standard filling of root canals with gutta-percha material. The aim of this review is to compare the different scaffold materials available today, find out the extent of knowledge about the growth factors related to pulp regeneration, pointing out the main limitations and devise a protocol for future regenerative procedures. Collagen scaffolds material have shown to be an optimal choice as they are biodegradable, can be autologous and are highly available. Insulin-like growth factor 1 and platelet derived growth factor have shown to be involved in cells proliferation. Vascular endothelial growth factor is one of the most important for vascular network proliferation. Cells isolation and high costs are the main obstacles. As a conclusion, the combination of a collagen scaffold, insulin-like growth factor 1, platelet derived growth factor, vascular endothelial growth factor and dental pulp stem cells from deciduous teeth (SHEDs) might give good outcomes in dental pulp regeneration


Asunto(s)
Humanos , Ingeniería de Tejidos/métodos , Endodoncia Regenerativa/métodos , Trasplante de Células Madre , Tejido Periapical/citología , Regeneración/fisiología , Células Madre/fisiología
7.
Int Urogynecol J ; 30(6): 853-868, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-30770967

RESUMEN

INTRODUCTION AND HYPOTHESIS: Perineal pain and dyspareunia are experienced by women undergoing a vaginal birth that can have short and longer term physical and psychological morbidities. This review aimed to determine the incidence of perineal pain and dyspareunia following spontaneous vaginal birth (SVB) with intact perineum, first and second-degree perineal trauma or episiotomy. METHODS: Searches of MEDLINE, EMBASE, CINAHL, AMED and MIDIRS (inception - December 2017) were undertaken with selection criteria of any study evaluating the effect of intact perineum, first- or second-degree perineal trauma on perineal pain or dyspareunia in women with SVB. RESULTS: Eighteen studies (8 RCTs and 10 NRSs) were included. Fourteen and 12 studies were undertaken to assess perineal pain and dyspareunia after SVB, respectively. Meta-analysis of 16 studies (3133 women) demonstrated that women at 2 days postpartum experienced nearly the same incidence of perineal pain whether perineal trauma existed or not. At 4-10 days postpartum there was a significant reduction in the incidence of perineal pain for both presence and absence of any perineal trauma. Episiotomy was associated with the highest rate of perineal pain. The incidence of dyspareunia was high at resumption of sexual intercourse following SVB with an intact perineum. At 12 months, women still experienced dyspareunia whether perineal trauma existed or not. CONCLUSIONS: Women experience perineal pain and dyspareunia regardless of the presence or absence of perineal trauma after SVB; nonetheless, the reported incidence is higher if perineal trauma occurred.


Asunto(s)
Dispareunia/epidemiología , Dolor/epidemiología , Parto , Perineo/lesiones , Episiotomía/efectos adversos , Femenino , Humanos , Incidencia , Perineo/cirugía , Periodo Posparto , Factores de Tiempo
8.
Cient. dent. (Ed. impr.) ; 15(1): 69-74, ene.-abr. 2018. tab, ilus
Artículo en Español | IBECS | ID: ibc-172863

RESUMEN

El éxito del tratamiento de endodoncia reside en una correcta limpieza y sellado tridimensional del sistema de conductos radiculares. En referencia al sellado, se han realizado numerosas investigaciones con el fin de encontrar el material ideal que evite la filtración tanto coronal como apical. Estos estudios in vitro se han llevado a cabo con una amplia gama de sistemas de medición, entre los que destacan los realizados con bacterias, glucosa, diferentes tintes o fluidos y técnicas microscópicas, ya sean ópticas o electrónicas de barrido (SEM). El objetivo de esta revisión bibliográfica es profundizar en las distintas técnicas de estudio que existen para la evaluación del sellado endodóntico y la filtración in vitro para tratar de establecer cuál es la más completa y capaz de aportar los resultados más reales y factibles, que pudieran extrapolarse a la práctica clínica


Success of endodontic treatment relies on the correct cleaning as well as on the three dimensional sealing of the root canal system. Regarding the sealing, many studies have been realized in order to find the ideal material that avoids coronal and apical filtration. This in vitro investigations have been carried out with a wide range of meassurement systems, among the ones are highlightables those dones with bacteria, glucose, different fluid dyes and micrhoscopic techniques, either optical or electronic scanning. The aim of this bibliographic review is to deep dive into the different techniques available for evaluating both in vitro sealing and filtration for try to stablish which is the most complete and accurate when providing results that night be extrapolated to clinical practice


Asunto(s)
Humanos , Materiales de Obturación del Conducto Radicular/análisis , Obturación del Conducto Radicular/métodos , Restauración Dental Permanente/métodos , Técnicas In Vitro , Materiales Biocompatibles/análisis
9.
Eur Endod J ; 3(1): 61-65, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-32161857

RESUMEN

OBJECTIVE: Root canal shaping is as important as irrigation and filling when attempting to obtain a high success rate in endodontic treatment. The creation of a glide path before the use of rotary instruments reduces the risk of posterior iatrogenic errors. The objective of the present study was to evaluate instrumentation time and root canal transport after using 2 different glide path rotary systems. METHODS: In total, 60 mesiobuccal root canals of mandibular molars, with curvature angles between 11° and 82°, were standardized to measure 15 mm. The specimens were divided into 2 groups, depending on their angles of curvature (11º-38º and 39º-82º), and further divided into 4 groups (n=15). Two groups were instrumented using the PathFile system and the other 2 using the ProFinder system. The angle and radius of curvature were measured at the most abrupt angle of curvature before and after instrumentation. Both measurements were analyzed and compared using AutoCAD software to determine canal transportation. Curvature angles were compared using Student's t test and the radii of curvature using the Wilcoxon test. The time for instrumentation was also evaluated using Student's t tests. RESULTS: There were no statistically significant differences between the two systems with respect to root canal transport (P>0.05); however, the ProFinder system took a longer time to create a glide path (P=0.004). CONCLUSION: Both systems were equally effective in creating a glide path; however, the PathFile system proved to be faster than the ProFinder system.

10.
Cient. dent. (Ed. impr.) ; 14(2): 135-139, mayo-ago. 2017. ilus, tab
Artículo en Español | IBECS | ID: ibc-165678

RESUMEN

La cirugía endodóntica tiene por objetivo eliminar quirúrgicamente el tejido patológico a nivel periapical y permitir el sellado hermético apical. Para ello resulta fundamental obturar la cavidad realizada con un material que sea biocompatible, insoluble y que impida la filtración bacteriana. Ninguno de los materiales de sellado clásicos ha sido capaz de satisfacer todos los requerimientos necesarios para ser denominado el material ideal en cirugía endodóntica. Sin embargo, con la introducción del Agregado Trióxido Mineral (MTA), se ha presentado un material altamente biocompatible que evita la filtración de bacterias y que es hidrófilo, por lo que podría emplearse en campos húmedos como son los tejidos apicales. El presente trabajo de revisión bibliográfica permitió investigar cuáles son las ventajas que aporta el MTA en cirugía endodóntica. Se han estudiado sus características con respecto a su biocompabilidad y capacidad de sellado. Además, se ha revisado cómo la literatura hace frente a sus desventajas como material de sellado, sobre todo, en referencia su difícil manejo y a su potencial de decoloración del diente obturado (AU)


Endodontic surgery treatment pretends to surgically remove pathological tissue in the periapical area, with the aim to obtain a hermetic and apical seal. For this, it is essential to seal the cavity with a material that is biocompatible in the periapical tissues, insoluble in oral fluid, and that prevents bacterial leakage in dental tissues. None of the conventionally used root end filling materials has been able to meet all the requirements to be designated as the ideal material for this treatment. however, with the introduction of Mineral Trioxide Aggregate (MTA), it was found to be a highly biocompatible material, which prevents bacterial leakage and is hydrophilic, so that the problem of its use in areas with moisture such as the apical tissues can be avoided. This literature review allowed us to investigate the advantages of the MTA in endodontic surgery. Its characteristics have been studied regarding its biocompatibility and sealing ability. Furthermore, it has been revised how the literature confronts its disadvantages regarding the troublesome handling and the potential discoloration of the filled tooth (AU)


Asunto(s)
Humanos , Selladores de Fosas y Fisuras/análisis , Pulpitis/cirugía , Apicectomía/métodos , Periodontitis Periapical/cirugía , Restauración Dental Permanente/métodos , Curación por Luz de Adhesivos Dentales
11.
Endodoncia (Madr.) ; 35(2): 65-75, abr.-jun. 2017. ilus
Artículo en Español | IBECS | ID: ibc-172306

RESUMEN

Objetivo: Comparar el porcentaje de área de gutapercha, cemento y huecos en conductos curvos obturados con sistemas con vástago y evaluar la influencia de la activación del cemento durante su colocación. Metodología: 120 conductos curvos de molares mandibulares fueron preparados a un diámetro apical ProFile 30, 0.04. Se obturaron con los sistemas GuttaCore, GuttaFusion o condensación lateral y AHplus (n = 40). Se subdividieron los grupos (n = 20) y se colocó el cemento con activación sónica o no. El cemento se mezcló con Rodamina B para permitir el análisis mediante microscopía confocal. Se calculó el área de gutapercha, cemento y huecos a 3, 6 y 9 mm del ápice. Se realizó el análisis estadístico utilizando ANOVA de dos vías. Para la comparación por pares se realizó el test de Sidak. Resultados: Cuando se comparan los sistemas de gutapercha a 3 mm, GF mostró un mejor comportamiento. CL obtuvo los peores resultados. No se encontró influencia entre los sistemas de obturación y la activación del cemento. Cuando se comparó el porcentaje de huecos entre todos los grupos, los perores resultados fueron para CL a 6 y 9 mm. Conclusiones: Bajo las condiciones de este estudio, el área de gutepercha, cemento y huecos depende del sistema de obturación utilizado. El uso de activación del cemento no influye en la calidad de la obturación


Aim: To compare the percentage of gutta-percha, sealer and voids in curved root canals filled with different gutta-percha carrier-based systems and to assess the influence of activation of the cement during its placement. Methodology: 120 curved canals of mandibular molars were prepared to an apical size ProFile 30, 0.04. They were filled with either GuttaCore, GuttaFusion or lateral condensation and AHplus (n=40). Groups were subdivided (n=20) and sonic activation or not during the placement of the cement was carried out. Cements were labelled with Rhodamine-B dye to allow analysis under confocal microscopy. Percentage of gutta-percha, sealer and voids area were calculated at 3, 6 and 9 mm from the apex. Statistical analysis was performed using two-way ANOVA test. To compare between the obturation systems Sidak correction for multiple comparisons was applied. Results: When comparing the gutta-percha systems at the 3 mm level, GF revealed a better performance. At 6 and 9mm, LC obtained the worst results. An influence between the obturation systems and the activation of the cement was not found. When comparing the percentage of voids among all the groups, worst results were found for LC at 6 and 9 mm. Conclusions: Under the conditions of this study, gutta-percha, sealer area and voids were dependent on the obturation system. The use of activation of the cement do not influence the quality of root filling


Asunto(s)
Humanos , Tratamiento del Conducto Radicular/métodos , Gutapercha/análisis , Materiales de Obturación del Conducto Radicular/análisis , Obturación del Conducto Radicular/métodos , Microscopía Confocal , Metacrilatos/uso terapéutico
13.
Cient. dent. (Ed. impr.) ; 8(3): 53-57, sept.-dic. 2011. ilus, tab
Artículo en Español | IBECS | ID: ibc-96000

RESUMEN

La xerostomía, como manifestación clínica de la hiposialia, es cada vez más frecuente en la práctica diaria debido a su etiología multifactorial: polimedicación, tratamiento oncológico, estrés, edad avanzada, etc. Los pacientes ven afectada en gran medida su calidad de vida, ya que padecerán alteraciones funcionales y orgánicas, siendo estas motivo de consulta. Debido a la inexistencia de un protocolo estandarizado de tratamiento para la xerostomía, se plantea el objetivo de analizarlos productos existentes con sus características e indicaciones, ya que el profesional debe conocerlos métodos terapéuticos. Siempre que sea posible, se tratarán las causas etiológicas que ocasionan xerostomía haciendo hincapié en las medidas preventivas. Deberá acompañarse de un tratamiento sintomático y de estimulación de la producción salival, para mejorar la calidad de vida. Para los casos más graves, se recurrirá a fármacos sistémicos. El tratamiento de la xerostomía es largo y complejo, con resultados muy variables. Se requiere seguir investigando en nuevas alternativas, comprobando y mejorando la eficacia de los métodos ya existentes (AU)


Xerostomia, as a clinical manifestation of hyposialia, is increasingly more frequent indaily practice due to its multifactor etiology: polymedication, oncological treatment, stress, advanced age, etc. The patients’ quality of life is affected to a great extent, since they will suffer functional and organic alterations, without these being a reason for consultation. Due to the non-existence of a standardized protocol of treatment for xerostomia, the objective was posed of analyzing the existing products with their characteristics and indications, since the professional must know the therapeutic methods. Whenever possible, it will deal with the etiological causes that bring about xerostomia, stressing the preventive measures. It must be accompanied by a symptomatic treatment and stimulation of the saliva production, in order to improve the quality of life. For the most serious cases, systemic medicines will be turned to. The treatment of xerostomia is long and complex, with quite variable results. Continued research in new alterations and verifying and improving the effectiveness of the existing methods are required (AU)


Asunto(s)
Humanos , Xerostomía/terapia , Terapia Combinada/métodos , Calidad de Vida , Distribución por Edad y Sexo , Xerostomía/epidemiología
14.
J Magn Reson Imaging ; 33(5): 1100-5, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21509867

RESUMEN

PURPOSE: To compare measurements of the fetal thymus obtained by magnetic resonance imaging (MRI) and ultrasound (US). MATERIALS AND METHODS: Written informed consent was obtained from the patients that participated in this Institutional Review Board-approved observational study. The study population consisted of 17 pregnant women carrying fetuses between 21 and 34 weeks of gestation with suspected abnormalities. The transverse diameter and perimeter of the thymus were measured in these fetuses at the level of an axial view of the thorax that includes the pulmonary, aorta, and superior vena cava. The degree of agreement between MRI and US measurements was determined using Lin's concordance correlation coefficient and Bland-Altman analysis. RESULTS: The mean (standard deviation, SD) gestational age at the time of the prenatal evaluation was 28.4 weeks (3.6). The thymus was measured by MRI and US in all cases. Comparison of the measurements from these two imaging modalities demonstrated a relatively good reproducibility with no evidence of systematic error. CONCLUSION: MRI and US measurements of the fetal thymus during the second half of pregnancy are comparable. This finding suggests that MRI can become a useful adjuvant to US for assessment of the fetal thymus.


Asunto(s)
Imagen por Resonancia Magnética/métodos , Timo/diagnóstico por imagen , Timo/embriología , Timo/patología , Ultrasonografía/métodos , Femenino , Edad Gestacional , Humanos , Masculino , Variaciones Dependientes del Observador , Embarazo , Reproducibilidad de los Resultados , Proyectos de Investigación
15.
Med Teach ; 28(1): 24-9, 2006 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16627317

RESUMEN

This paper briefly reviews the current situation of Latin American medical schools and the search to improve the quality and professionalism of medical education through the region. Institutional evaluation and accreditation programs based on nationally ongoing developing standards have been accepted, now optimized and complemented by the framework of the Global & International Standards of Medical Education working jointly with the WFME. More recently, the process has evolved to look into the quality of the outcomes of the medicals as seen by examinations implemented at the end of medical studies and the initiation of medical practice. In addition, there is vision for the application of new programs such as the global minimum essential requirements advanced by the Institute for International Medical Education (IIME). The PanAmerican Federation of Associations of Medical Schools (PAFAMS), an academic, non-governmental organization, is fostering the exchange of ideas and experiences among members, associations and affiliated medical schools geared to focus on the quality and professionalism of the graduates of medical schools in Latin America. These actions also aim to consolidate databases of information on medical education and innovative endeavors in continuing professional education and development through e-learning projects in the region.


Asunto(s)
Educación Médica/normas , Educación Médica/tendencias , Acreditación/organización & administración , Acreditación/normas , Acreditación/tendencias , Asignación de Recursos para la Atención de Salud/organización & administración , Asignación de Recursos para la Atención de Salud/tendencias , América Latina , Médicos/provisión & distribución , Evaluación de Programas y Proyectos de Salud , Calidad de la Atención de Salud/normas , Calidad de la Atención de Salud/tendencias , Facultades de Medicina/organización & administración
16.
Microbiology (Reading) ; 144 ( Pt 2): 543-553, 1998 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9493390

RESUMEN

6-Deoxyerythronolide B synthase (DEBS) is a large multifunctional enzyme that catalyses the biosynthesis of the erythromycin polyketide aglycone. DEBS is organized into six modules, each containing the enzymic domains required for a single condensation of carboxylic acid residues which make up the growing polyketide chain. Module 1 is preceded by loading acyltransferase (AT-L) and acyl carrier protein (ACP-L) domains, hypothesized to initiate polyketide chain growth with a propionate-derived moiety. Using recombinant DNA technology several mutant strains of Saccharopolyspora erythraea were constructed that lack the initial AT-L domain or that lack both the AT-L and ACP-L domains. These strains were still able to produce erythromycin, although at much lower levels than that produced by the wild-type strain. In addition, the AT-L domain expressed as a monofunctional enzyme was able to complement the deletion of this domain from the PKS, resulting in increased levels of erythromycin production. These findings indicate that neither the initial AT-L nor the ACP-L domains are required to initiate erythromycin biosynthesis; however, without these domains the efficiency of erythromycin biosynthesis is decreased significantly. It is proposed that in these mutants the first step in erythromycin biosynthesis is the charging of KS1 with propionate directly from propionyl-CoA.


Asunto(s)
Proteína Transportadora de Acilo/genética , Aciltransferasas/genética , Eritromicina/metabolismo , Complejos Multienzimáticos/genética , Saccharopolyspora/genética , Saccharopolyspora/metabolismo , Proteína Transportadora de Acilo/metabolismo , Acilcoenzima A/metabolismo , Aciltransferasas/metabolismo , Secuencia de Bases , Mapeo Cromosómico , Clonación Molecular , Cartilla de ADN/genética , ADN Bacteriano/genética , Eritromicina/química , Genes Bacterianos , Prueba de Complementación Genética , Péptidos y Proteínas de Señalización Intercelular , Datos de Secuencia Molecular , Estructura Molecular , Complejos Multienzimáticos/química , Complejos Multienzimáticos/metabolismo , Plásmidos , Reacción en Cadena de la Polimerasa , Proteínas/metabolismo , Recombinación Genética , Saccharopolyspora/enzimología , Eliminación de Secuencia , Transformación Genética
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