Microtubule binding of the human augmin complex is directly controlled by importins and Ran-GTP.

Mitotic spindle assembly during cell division is a highly regulated process. Ran-GTP produced around chromosomes controls the activity of a multitude of spindle assembly factors by releasing them from inhibitory interaction with importins. A major consequence of Ran-GTP regulation is the local stimulation of branched microtubule nucleation around chromosomes, which is mediated by the augmin complex (composed of the eight subunits HAUS1-HAUS8), a process that is crucially important for correct spindle assembly. However, augmin is not known to be a direct target of the Ran-GTP pathway, raising the question of how its activity is controlled. Here, we present the in vitro reconstitution of Ran-GTP-regulated microtubule binding of the human augmin complex. We demonstrate that importins directly bind to augmin, which prevents augmin from binding to microtubules. Ran-GTP relieves this inhibition. Therefore, the augmin complex is a direct target of the Ran-GTP pathway, suggesting that branching microtubule nucleation is directly regulated by the Ran-GTP gradient around chromosomes in dividing cells.

[Histological characteristics of bovine dentin using Masson's Trichrome staining]. / Características histológicas de la dentina bovina mediante tinción Tricrómica de Masson.

Objectives: Identify the histological characteristics of bovine dentin using histological technique by decalcification with Masson's Trichrome staining. Materials and Methods: This was an observational and descriptive study using units of analysis. Bovine teeth were used, which were subjected to a decalcification technique and Masson's trichrome staining. Microscopic observation and registration of the structures was carried out. Results: In the microscopic observation of the teeth subjected to decalcification, dentin, predentin and the structural organization of the tubular and peritubular dentin were observed. The odontoblasts arranged in a palisade with the odontoblastic process included within the dentinal tubule and the periprocedural space. The presence of interglobular dentin is not observed in areas of coronary dentin. The histomorphological pattern corresponding to dentin-predentin-pulp is arranged in a similar way to human teeth. Conclusions: Bovine dentin constitutes an ideal substrate for in vitro research work with dental biomaterials, since it presents histological characteristics similar to bovine teeth; the absence of interglobular dentin would not represent a significant difference according to what was observed in this study.

APC couples neuronal mRNAs to multiple kinesins, EB1, and shrinking microtubule ends for bidirectional mRNA motility.

Understanding where in the cytoplasm mRNAs are translated is increasingly recognized as being as important as knowing the timing and level of protein expression. mRNAs are localized via active motor-driven transport along microtubules (MTs) but the underlying essential factors and dynamic interactions are largely unknown. Using biochemical in vitro reconstitutions with purified mammalian proteins, multicolor TIRF-microscopy, and interaction kinetics measurements, we show that adenomatous polyposis coli (APC) enables kinesin-1- and kinesin-2-based mRNA transport, and that APC is an ideal adaptor for long-range mRNA transport as it forms highly stable complexes with 3'UTR fragments of several neuronal mRNAs (APC-RNPs). The kinesin-1 KIF5A binds and transports several neuronal mRNP components such as FMRP, PURα and mRNA fragments weakly, whereas the transport frequency of the mRNA fragments is significantly increased by APC. APC-RNP-motor complexes can assemble on MTs, generating highly processive mRNA transport events. We further find that end-binding protein 1 (EB1) recruits APC-RNPs to dynamically growing MT ends and APC-RNPs track shrinking MTs, producing MT minus-end-directed RNA motility due to the high dwell times of APC on MTs. Our findings establish APC as a versatile mRNA-kinesin adaptor and a key factor for the assembly and bidirectional movement of neuronal transport mRNPs.

Uso de dientes bovinos como elección para trabajos de investigación en odontología / The use of bovine teeth as a choice for dental investigation papers

Los dientes animales de las diferentes especies (hu- mano, equino, cerdo, etc.) están constituidos histológi- camente por cuatro tejidos fundamentales. Ellos son: esmalte, dentina, cemento y pulpa dental. Su compo- sición, estructura, morfología y tamaño son disímiles para cada género. Según numerosas investigaciones, los dientes de bovino serían los de elección por ser de fácil obtención y por tener muy pocas, o ninguna, diferencias tanto a nivel macro como microscópico con respecto a los dientes humanos. El objetivo de la presente revisión es aportar información actualizada acerca de las características histológicas de los tejidos dentarios bovinos y profundizar el conocimiento de las similitudes y diferencias de los dientes bovinos y humanos dando soporte a otros estudios compa- rativos y promoviendo la utilización de las piezas dentarias bovinas en trabajos de investigación en odontología (AU)

The animal teeth of the different species (human, equine, pig, etc.) are histologically constituted by four fundamental tissues: enamel, dentin, cement and dental pulp. Their composition, structure, morphology and size are dissimilar for each gender. According to numerous investigations, bovine teeth would be the ones of choice because they are easy to obtain and have very few or no differences, both at the macro and microscopic levels, with respect to human teeth. The objective of this review is to provide updated information about the histological characteristics of bovine dental tissues and deepen the knowledge of the similarities and differences between bovine and human teeth, supporting other comparative studies and promoting the use of bovine dental pieces in research work in dentistry (AU)

Matrix-screening reveals a vast potential for direct protein-protein interactions among RNA binding proteins.

RNA-binding proteins (RBPs) are crucial factors of post-transcriptional gene regulation and their modes of action are intensely investigated. At the center of attention are RNA motifs that guide where RBPs bind. However, sequence motifs are often poor predictors of RBP-RNA interactions in vivo. It is hence believed that many RBPs recognize RNAs as complexes, to increase specificity and regulatory possibilities. To probe the potential for complex formation among RBPs, we assembled a library of 978 mammalian RBPs and used rec-Y2H matrix screening to detect direct interactions between RBPs, sampling > 600 K interactions. We discovered 1994 new interactions and demonstrate that interacting RBPs bind RNAs adjacently in vivo. We further find that the mRNA binding region and motif preferences of RBPs deviate, depending on their adjacently binding interaction partners. Finally, we reveal novel RBP interaction networks among major RNA processing steps and show that splicing impairing RBP mutations observed in cancer rewire spliceosomal interaction networks. The dataset we provide will be a valuable resource for understanding the combinatorial interactions of RBPs with RNAs and the resulting regulatory outcomes.

Producción de nitrosaminas por Candida albicans y su relación con lesiones de la cavidad oral. Revisión de la literatura / Nitrosamine production by Candida albicans and its relationship with lesions of the oral cavity. A literature review

El objetivo de esta revisión es presentar el estado del conocimiento respecto a la capacidad que tiene Candida albicans de producir nitrosaminas y de cómo estas se relacionan con la posible malignización de lesiones de la cavidad bucal. La candidiasis oral (CO) es una infección frecuente de la mucosa bucal provocada por hongos de la familia Candida spp. Estos hongos son integrantes de la flora bucal habitual, pero, por diferentes factores locales y sistémicos, pueden producir micosis superficiales. Entre las distintas especies, albicans, es la más frecuente en la cavidad bucal.Posee gran variedad de factores de virulencia, uno de ellos la capacidad de nitrosación de nitratos y nitritos presentes en saliva que últimamente se ha considerado relacionada a la malignización de lesiones mucosas de la cavidad bucal y otras como el estómago.

This literature review was carried out to approach the state of knowledge regarding the capacity of Candida Albicans to produce nitrosamines and how these are related to the possible malignancy of lesions in the oral cavity. Oral candidiasis (CO) is a frequent infection of the oral mucosa caused by fungi of the family Candida spp. These fungi are part of the usual oral flora but, due to different local and systemic factors, can produce superficial mycosis. Among the different species, Albicans is the most frequent in the oral cavity. It has a great variety of virulence factors, one of them the nitrosation capacity of nitrates and nitrites present in saliva that lately has been considered related to the malignization of mucosal lesions of the oral cavity and others such as the stomach.

Análisis del espesor de los tejidos duros en la dentición permanente humana / Analysis of the thickness of hard tissues in human permanent dentition

Objetivo. Verificar el espesor de los tejidos duros dentarios en la actualidad. Métodos. Estudio observacional, descriptivo y transversal. Se utilizaron 94 piezas dentarias permanentes naturales y humanas existente en la morfoteca de la facultad de odontología de la Universidad Nacional del Nordeste y recopiladas durante 2004 al 2014, libres de lesiones, restauraciones, con corona y raíz completas. Se seleccionaron ocho muestras de cada grupo (incisivos, caninos, premolares y molares) para medir el espesor de los tejidos duros en los tercios incisal, oclusal, central, cervical y apical. Se utilizó una morsa plana modelo AA y discos de carborundum en micromotor tipo Dremel 4000 para realizar cortes longitudinales en sentido mesiodistal, de cada pieza seleccionada y se procedió a pulir la superficie con piedra pómez hasta obtener el mínimo espesor. La medición se realizó en milímetros con digital microscope, resolution up to 2M pixel, 25-400x. Resultados. El tejido de mayor espesor en todos los grupos dentarios fue la dentina cuyo valor fue 1,53 mm a 5,16 mm. Le siguió en orden el esmalte con 0,87 mm a 3,47 mm según el lugar de ubicación y el tejido más delgado lo representó el cemento con valores entre 0,18 mm y 0,78 mm. El mayor espesor de esmalte y dentina fue registrado en el grupo premolar, mientras que el mayor espesor de cemento, en el grupo molar. Conclusión. El trabajo realizado ha permitido observar diferencias significativas en los espesores de los tejidos dentarios, medidos en piezas dentarias permanentes humanas.

Objective. To verify the thickness of dental hard tissues at present. Methods. Observational, descriptive and cross-sectional study. Ninety four human permanent teeth existing in the library of the Faculty of Dentistry of the National Northeast University were collected during 2004-2014, these were free of injuries and restorations, with full crowns and root were used. Eight samples from each group (incisors, canines, premolars, and molars) were selected to measure the thickness of hard tissues of incisal, occlusal, central, cervical, and apical thirds. A Model AA flat vice and carborundum discs were used in a Dremel 4000 micromotor to make longitudinal cuts in the mesiodistal direction of each selected piece and the surface was polished with a pumice stone until minimum thickness was obtained. The measurement was made in millimeters with a digital microscope, resolution up to 2M pixel, 25 - 400x. Results. The thickest tissue in all the dental groups was dentin whose value was 1.53 mm to 5.16 mm, enamel followed in order with 0.87 mm to 3.47 mm depending on the location, and the thinnest tissue was cement with values between 0.18 mm and 0.78 mm. The greatest thickness of enamel and dentin was registered in the premolar group, while the greatest thickness of cement, in the molar group. Conclusion. This work has allowed us to observe significant differences in the thickness of the dental tissues, measured in permanent human teeth.

A reconstituted mammalian APC-kinesin complex selectively transports defined packages of axonal mRNAs.

Through the asymmetric distribution of messenger RNAs (mRNAs), cells spatially regulate gene expression to create cytoplasmic domains with specialized functions. In neurons, mRNA localization is required for essential processes such as cell polarization, migration, and synaptic plasticity underlying long-term memory formation. The essential components driving cytoplasmic mRNA transport in neurons and mammalian cells are not known. We report the first reconstitution of a mammalian mRNA transport system revealing that the tumor suppressor adenomatous polyposis coli (APC) forms stable complexes with the axonally localized ß-actin and ß2B-tubulin mRNAs, which are linked to a kinesin-2 via the cargo adaptor KAP3. APC activates kinesin-2, and both proteins are sufficient to drive specific transport of defined mRNA packages. Guanine-rich sequences located in 3'UTRs of axonal mRNAs increase transport efficiency and balance the access of different mRNAs to the transport system. Our findings reveal a minimal set of proteins sufficient to transport mammalian mRNAs.

rec-Y3H screening allows the detection of simultaneous RNA-protein interface mutations.

Understanding which proteins and RNAs directly interact is crucial for revealing cellular mechanisms of gene regulation. Efficient methods allowing to detect RNA-protein interactions and dissect the underlying molecular origin for RNA-binding protein (RBP) specificity are in high demand. The recently developed recombination-Y3H screening (rec-Y3H) enabled many-by-many detection of interactions between pools of proteins and RNA fragments for the first time. Here, we test different conditions for protein-RNA interaction selection during rec-Y3H screening and provide information on the screen performance in several selection media. We further show that rec-Y3H can detect the nucleotide and amino acid sequence determinants of protein-RNA interactions by mutating residues of interacting proteins and RNAs simultaneously. We envision that systematic RNA-protein interface mutation screening will be useful to understand the molecular origin of RBP selectivity and to engineer RBPs with targeted specificities in the future.

Acción anticariogénica del propóleo / Anticariogenic action of propolis

En la actualidad, el estudio de las sustancias naturales para tratar patologías es muy frecuente, más aún aquellas que contienen polifenoles, principalmente flavonoides, como es el caso del propóleo. El propóleo es un producto elaborado por las abejas, que se caracteriza por poseer múltiples propiedades, siendo una de las más destacadas la antimicrobiana. El mecanismo antimicrobiano involucra la inhibición de ácidos nucleicos y la degradación de la membrana citoplasmática de los microorganismos. En varias investigaciones se comprobó que el propóleo actúa inhibiendo la actividad del Streptocuccus mutans, principal microorganismo productor de caries dental. Esto motivó la realización de la presente revisión bibliográfica sobre la acción del propóleo como agente antimicrobiano (AU)

At the present, the study of natural substances to treat pathologies is very frequent, and more those that contain polyphenols, mainly flavonoids, as is the case of propolis. It is a product made by bees, which is characterized by having multiple properties, one of the most prominent being the antimicrobial. The antimicrobial mechanism involves the inhibition of nucleic acids and the degradation of the cytoplasmic membrane of microorganisms. In extensive research it was found that propolis acts by inhibiting the activity of Streptococcus mutans, the main organism producing dental caries. This motivated the realization of the present bibliographical review on the action of propolis as an antimicrobial agent (AU)

Aplicaciones del cultivo celular en odontología / Applications of cell culture in dentistry

Las ciencias básicas, la medicina oral y los nuevos avanzces en biotecnología y bioinformática constituyen un gran campo de investigación dentro de la odontología actual. En este sentido, dichos avances están proporcionandoun nuevo conjunto de estrategias terapéuticas para el manejo clínico de los pacientes con dolencias dentales y craneofaciales. Es importante destacar que las disciplinas relacionadas con las ciencias básicas, la medicina oral, la biotecnología y la bioinformática, han contribuido de manera trascendental al entendimiento de la fisiología y lasdiversas patologías que afectan las condiciones de normalidad del sistema bucal. La ingeniería tisular se considera como un enfoque prometedor para la odontología regenerativa, con el objetivofinal de reemplazar morfológica y funcionalmente los tejidos periodontales y/o los dientes perdidos a través dela síntesis in vitro de sustitutos análogos tisulares, considerando que el diente y las estructuras periodontales son importantes órganos del complejo craneofacial, los tratamientos utilizados para las enfermedades que los afectan no lo restauran completamente. La odontología clínica está incursionando en una nueva era en donde el enfoque terapéutico es el uso de terapia génica, terapia celular, ingeniería tisular y lamedicina regenerativa, ampliando el arsenal de posibilidades para nuestros pacientes. Una línea de investigaciónfundamental en ingeniería tisular y medicina regenerativa son las células madres. Como parte de los nuevos avances de la odontología a nivel mundial, científicos e investigadores del mundo aplican la bioingeniería para lograr reconstrucciones maxilofaciales,regeneraciones óseas y reconstrucciones de piezas dentales a partir de células madre como parte de tratamientos inovadores...

Utilización de propóleos en odontología / The use of propolis in dentistry

El propóleos es un producto natural elaborado por las abejas a partir de la secreción que recogen de ciertas especies vegetales y que, luego de modificarlas con sus secreciones salivares, lo transportan al interior de la colmena. Así, el propóleos es responsable directo de garantizar la asepsia de la colmena. Múltiples investigaciones científicas atribuyeronal propóleos propiedades antioxidantes, antibacterianas, antivirales, fungicidas, cicatrizantes, antiinflamatorias, anestésicas, inmunomoduladoras antitumorales. Asimismo, en bastas investigaciones se comprobó que el propóleos actúa inhibiendo la actividad de los Streptococo mutans, principal microorganismo productor de caries dental. Esto motivó la realización de la presente revisión bibliográfica sobre las propiedades y utilización del propóleos en odontología.

Propolis is a natural product made by bees fromcollecting secretion of certain plant speciesand, after modifying their salivary secretions,transported into the hive. So propolis is directlyresponsible for ensuring the cleanliness of the hive.Multiple scientific research attributed to propolisantioxidant, antibacterial, antiviral, fungicide, healing,anti-inflammatory, anesthetic,immunomodulatory and antitumor properties.Also in rough investigations it was foundthat propolis acts by inhibiting the activityof Streptococcus mutans, the main producingmicroorganism tooth decay. This led to therealization of this literature review on theproperties and use of propolis in dentistry.

Histomorfología de la atrición en dientes temporarios / Histomorphology of attrition in temporary teeth

En la Facultad de Odontología de la Universidad Nacional del Nordeste, provincia de Corrientes, Argentina, se desarrolló un trabajo de investigación en el cual se estudiaron las características histológicas que presentaban el esmalte y la dentina de piezas dentarias temporarias bajo el proceso fisiológico de la atrición. Para dicho estudio, se obtuvieron 25 piezas dentarias temporarias de pacientes que concurrieron a la Cátedra de Odontopediatría para su atención. Las muestras fueron protocolizadas y clasificadas según la escala de desgaste dentario de Gerasimov modificada. Las piezas dentarias se procesaron mediante la técnica de desgaste para su observación al microscopio óptico, determinándose que el 48% de los casos el desgaste correspondía a grado I, el 36% al grado II y el resto al grado III. En los casos que afectó al esmalte únicamente se observó la sección de los prismas del esmalte. Cuando afectó esmalte y dentina en los grados II y III de la escala se observan tanto casos de dentina esclerótica como de trayectos muertos.

A research project was conducted at the School of Dentistry of the National University of the Northeast, Corrientes, Argentina. The histologic features of the enamel and dentin of temporary teeth under the physiological process of attrition were studied. For this study 25 temporary teeth were obtained from patients attending the Pediatric Dentistry Department for dental care. Samples were categorized and classified according to a modified version of Gerasimov’s tooth wear scale. The teeth were processed using the technical wear approach for observation through a microscope. It was determined that 48% of cases showed grade I wear, 36% grade II wear, and 16% grade III wear. In cases where only the dentin was affected, the section of the enamel prisms was observed. When both the enamel and the dentin were affected, reaching grade II and grade III wear levels, cases of both sclerotic dentin and dead tracts were observed.