A novel spalt gene expressed in branchial arches affects the ability of cranial neural crest cells to populate sensory ganglia

Cranial neural crest cells differentiate into diverse derivatives including neurons and glia of the cranial ganglia, and cartilage and bone of the facial skeleton. Here, we explore the function of a novel transcription factor of the spalt family that might be involved in early cell-lineage decisions of the avian neural crest. The chicken spalt4 gene (csal4) is expressed in the neural tube, migrating neural crest, branchial arches and, transiently, in the cranial ectoderm. Later, it is expressed in the mesectodermal, but not neuronal or glial, derivatives of midbrain and hindbrain neural crest. After over-expression by electroporation into the cranial neural tube and neural crest, we observed a marked redistribution of electroporated neural crest cells in the vicinity of the trigeminal ganglion. In control-electroporated embryos, numerous, labeled neural crest cells ([similar]80% of the population) entered the ganglion, many of which differentiated into neurons. By contrast, few ([similar]30% of the population) spalt-electroporated neural crest cells entered the trigeminal ganglion. Instead, they localized in the mesenchyme around the ganglionic periphery or continued further ventrally to the branchial arches. Interestingly, little or no expression of differentiation markers for neurons or other cell types was observed in spalt-electroporated neural crest cells

Spalt4 mediates invagination and otic placode gene expression in cranial ectoderm

Vertebrate placodes are regions of thickened head ectoderm that contribute to paired sensory organs and cranial ganglia. We demonstrate that the transcription factor Spalt4 (also known as Sall4) is broadly expressed in chick preplacodal epiblast and later resolves to otic, lens and olfactory placodes. Ectopic expression of Spalt4 by electroporation is sufficient to induce invagination of non-placodal head ectoderm and prevent neurogenic placodes from contributing to cranial ganglia. Conversely, loss of Spalt4 function in the otic placode results in abnormal otic vesicle development. Intriguingly, Spalt4 appears to initiate a placode program appropriate for the axial level but is not involved in later development of specific placode fates. Fgfs can regulate Spalt4, since implantation of Fgf2 beads into the area opaca induces its expression. The results suggest that Spalt4 is involved in early stages of placode development, initiating cranial ectodermal invagination and region-specific gene regulatory networks

Identification and dissection of a key enhancer mediating cranial neural crest specific expression of transcription factor, Ets-1

Neural crest cells form diverse derivatives that vary according to their level of origin along the body axis, with only cranial neural crest cells contributing to facial skeleton. Interestingly, the transcription factor Ets-1 is uniquely expressed in cranial but not trunk neural crest, where it functions as a direct input into neural crest specifier genes, Sox10 and FoxD3. We have isolated and interrogated a cis-regulatory element, conserved between birds and mammals, that drives reporter expression in a manner that recapitulates that of endogenous Ets-1 expression in the neural crest. Within a minimal Ets-1 enhancer region, mutation of putative binding sites for SoxE, homeobox, Ets, TFAP2 or Fox proteins results in loss or reduction of neural crest enhancer activity. Morpholino-mediated loss-of-function experiments show that Sox9, Pax7, Msx1/2, Ets-1, TFAP2A and FoxD3, all are required for enhancer activity. In contrast, mutation of a putative cMyc/E-box sequence augments reporter expression, consistent with this being a repressor binding site. Taken together, these results uncover new inputs into Ets-1, revealing critical links in the cranial neural crest gene regulatory network

Stage-dependent plasticity of the anterior neural folds to form neural crest

The anterior neural fold (ANF) is the only region of the neural tube that does not produce neural crest cells. Instead, ANF cells contribute to the olfactory and lens placodes, as well as to the forebrain and epidermis. Here, we test the ability of the ANF to form neural crest by performing heterotopic transplantation experiments in the chick embryo. We find that, at the neurula stage (HH stage 7), the chick ANF retains the ability to form migrating neural crest cells when transplanted caudally to rostral hindbrain levels. This ability is gradually lost, such that by HH9, this tissue appears to no longer have the potential to form neural crest. In contrast to the ANF, hindbrain dorsal neural folds transplanted rostrally fail to contribute to the olfactory placode but instead continue to generate neural crest cells. The transcription factor GANF is expressed in the ANF and its morpholino-mediated knock-down expands the neural crest domain rostrally and results in the production of migratory cells emerging from the ANF; however, these cells fail to express the HNK1 neural crest marker, suggesting only partial conversion. Our results show that environmental factors can imbue the chick anterior neural folds to assume a neural crest cell fate via a mechanism that partially involves loss of GANF

Antifungal and post-antifungal effects of chlorhexidine, fluconazole, chitosan and its combinations on Candida albicans.

Objective: The aim of this work was to assess the antifungal and post-antifungal effects of chlorhexidine, fluconazole, chitosan and its combinations on virulence factors of Candida albicans. Study Design: Ten isolated strains of Candida albicans obtained from 10 patients with oral candidiasis and a collection strain of C. albicans were treated with antifungal agents in different concentrations or combinations of them. Virulence factors analyzed were the cell surface hydrophobicity, the germinative tube development, the phospholipase activity and the post-antifungal effect of that exposure. Results: Virulence factors of the isolated strains obtained from patients together with the collection strain showed significant decreases with the different antifungal treatments, except for hydrophobicity and phospholipase activity. The development of germinative tube was the most sensitive factor to all the antifungal agents used. Untreated strains as well as the ones treated with antifungal agents showed a positive correlation among the virulence factors analyzed. No synergic effects arose from the combinations of the used drugs. Conclusions: C. albicans isolated strains from patients showed high phospholipase activity and germinative tube production, which corroborates their capacity to infect the oral mucosa and the high prevalence of species. As a whole, our results imply that short exposures to sub-inhibitory concentrations of the antifungal agents under analysis, isolated or combined, can modulate the way virulence factors get manifested, thus decreasing their pathogenicity.publishedVersio

Lunatic fringe causes expansion and increased neurogenesis of trunk neural tube and neural crest populations

Both neurons and glia of the PNS are derived from the neural crest. In this study, we have examined the potential function of lunatic fringe in neural tube and trunk neural crest development by gain-of-function analysis during early stages of nervous system formation. Normally lunatic fringe is expressed in three broad bands within the neural tube, and is most prominent in the dorsal neural tube containing neural crest precursors. Using retrovirally-mediated gene transfer, we find that excess lunatic fringe in the neural tube increases the numbers of neural crest cells in the migratory stream via an apparent increase in cell proliferation. In addition, lunatic fringe augments the numbers of neurons and upregulates Delta-1 expression. The results indicate that, by modulating Notch/Delta signaling, lunatic fringe not only increases cell division of neural crest precursors, but also increases the numbers of neurons in the trunk neural crest

Efecto del quitosán de alto peso molecular y del alginato de sodio sobre la hidrofobicidad y adhesión de Candida albicans a células

Objetivo: Evaluar el efecto del quitosán de alto peso molecular (QAPM) y del alginato de sodio (NaAL) sobre la hidrofobicidad superficial de Candida albicans y la adhesión de esta levadura a células epiteliales y fibroblastos de distinto origen. Diseño del estudio: Para el estudio de la hidrofobicidad, las levaduras (n=7) se hicieron crecer en agar glucosado de Sabouraud suplementado con QAPM o NaAL o en ausencia de los mismos (controles). La determinación de la hidrofobicidad se realizó por el método de adhesión a hidrocarburos utilizando dos solventes orgánicos (xileno y cloroformo). En los estudios de adhesión, las levaduras se pusieron en contacto con soluciones de biopolímeros y luego se enfrentaron a diferentes células (fibroblastos humanos y de rata y células epiteliales Hep-2). La cuantificación se realizó por microscopía óptica. Resultados: Se observó una disminución del 44% de la hidrofobicidad en presencia de QAPM y del 82%, con NaAL, o del 30% con QAPM y 19% con NaAL, cuando los solventes orgánicos empleados fueron cloroformo o xileno, respectivamente. La adhesión de C. albicans a células epiteliales y fibroblastos humanos disminuyó significativamente con ambos biopolímeros. En el caso de los fibroblastos de encía de rata, sólo se observó una disminución con NaAL. En ninguno de los experimentos se observaron diferencias significativas en asociación al tipo de fibroblasto empleado. Conclusiones: Los biopolímeros resultaron efectivos en la reducción de la hidrofobicidad y la adhesión de C. albicans a células, las cuales son importantes factores de virulencia relacionados con la colonización de los tejidos blandos del hospedador o superficies acrílicas presentes en el sistema estomatognático.The aim of the present paper is to evaluate the effect of the high molecular weight chitosan (HMWC) and of sodium alginate (NaAL) on surface hydrophobicity of Candida albicans and on adhesion of the yeast to epithelial cells and fibroblasts of different proceeding. For this study, a collection strain and seven isolates of C. albicans from saliva (patients with denture stomatitis) were grown in Sabouraud glucose agar supplemented with HMWC or NaAL or in absence of them (control). Hydrophobicity was determined by adhesion to hydrocarbons method using two organic media (xylene and chloroform). For adhesion experiments, aqueous suspensions of yeasts were contacted with solutions of biopolymers and different cells (rat and human fibroblasts and epithelial cells Hep-2). The quantification of adhesion was made by optical microscopy. Results: a decrease in hydrophobicity was observed in the presence of HMWC (44%) and of NaAL (82%) when chloroform was employed as organic medium, meanwhile the decreases were of 30% with HMWC and 19% with NaAL in the presence of xylene. Adhesion of C. albicans to epithelial cells and human fibroblasts decreased significantly with both biopolymers. In the case of rat fibroblasts, a decrease was observed only with NaAL. None of experiments showed significant differences associated to fibroblast type. Conclusions: biopolymers showed effectiveness in reducing hydrophobicity and adhesion of C. albicans to cells, which are important virulence factors related to colonization of the soft tissues of host or acrylic surfaces present in the oral system

Lactobacillus: modulador en la virulencia de algunos integrantes de la microbiota bucal

Fil: Barembaum, Silvina Ruth. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra Introducción a la Física y Química Biológica B; Argentina.Fil: Scatena, María Gabriela. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra Química Biológica B; Argentina.Fil: Socolovsky, Javier Andrés. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra Química Biológica B; Argentina.Fil: Azcurra, Ana Isabel. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra de Biología Celular B; Argentina.OBJECTIVE: To evaluate the modulating effect of L. acidophilus (LA) and LA culture supernatant (SobLac) on thebiofilm formation ability of C. albicans (CA) and S. mutans(SM) and filamentation of the fungus. MethodsBiofilm formation: Biofilm was developed from reference strains of CA (SC 5314) and SM (ATCC 25175) in thepresence or absence of LA (ATCC 4356) or SobLac (15 and 30% v/v) The XTT reduction method was used toquantify the biofilm formation. Filamentation of CA: A suspension of CA was incubated with fetal bovine serum in thepresence or absence of LA or SobLac (37°C for 2.5 h). The germ tube/yeast ratio (TG/L) was determined. Data wereanalyzed by t-test, after testing for normal distribution of data (Shapiro-Wilks); p ≤ 0.05 for statistical significance wasestablished.RESULTS: A decrease in CA biofilm formation was observed in the presence of LA (P= 0.0025) and SobLac (15%P= 0.0079 and 30% p=0.024 respectively). With SM a decrease in biobilm formation was only observed with thepresence of SobLac at 30% (P=0.0164). When evaluating the effect on CA filamentation, the GT/Y proportion(control 38.7±10.1) showed a decrease in the presence of LA (22±12; P= 0.0430) and with SobLac at 30%(10.5±8.8; P=0.0073).CONCLUSIONS: The results of this work show the inhibitory capacity of probiotics and their soluble products onvirulence factors of CA and SM, opening the possibility of new fields of study on oral microbiota.OBJETIVO: Evaluar el efecto modulador del probiotico Lactobacillus acidophilus (LA) y el sobrenadante de cultivo de Lactobacillus acidophilus (SobLac) sobre la capacidad de formación de biofilm de Candida albicans (CA) y de Streptococcus mutans(SM) y la filamentación del hongo. MÉTODOS: Formación de biofilm: A partir de una cepa de colección de Candida albicans (SC 5314) y Streptococcus mutan (ATCC 25175) se desarrollaron biofilm en presencia o en ausencia de Lactobacillus acidophilus (ATCC 4356) o del SobLac (15 y 30% v/v) Para cuantificar el biofilm se empleó el método de reducción de la sal de tetrazolio (XTT). Filamentación de CA: Una suspensión de Candida albicans se incubó con suero fetal bovino en presencia o en ausencia de LA o de SobLac (37ºC durante 2,5 h). Se determinó la relación de tubos germinativos/levaduras (TG/L). Los datos fueron analizados mediante el test de t, previa comprobación de la distribución normal de los mismos (Shapiro-Wilks), nivel de p ≤ 0,05 para la significación estadística. RESULTADOS: Se observó una disminución en el desarrollo del biofilm de CA en presencia de LA (P= 0,0025) y SobLac (15% P= 0,0079 y 30% p=0,024 respectivamente). En el desarrollo de biofilm de SM sólo se observó disminución con la presencia de SobLac al 30%(P=0,0164). Al evaluar el efecto sobre la filamentación de CA, la proporción TG/L (38,7±10,1) mostró una disminución en presencia de LA (22±12; p= 0,0430) y con SobLac al 30 % (10,5±8,8; p=0,0073). CONCLUSIONES: Los resultados de este trabajo muestran la capacidad inhibitoria de los probióticos y de sus productos solubles sobre factores de virulencia de CA y SM, abriendo la posibilidad de nuevos campos de estudio sobre la microbiota bucalhttps://saio.org.ar/?page_id=104Fil: Barembaum, Silvina Ruth. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra Introducción a la Física y Química Biológica B; Argentina.Fil: Scatena, María Gabriela. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra Química Biológica B; Argentina.Fil: Socolovsky, Javier Andrés. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra Química Biológica B; Argentina.Fil: Azcurra, Ana Isabel. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra de Biología Celular B; Argentina.Otras Ciencias de la Salu

Análisis del estrés laboral en una PYME del sector de la construcción de la Ciudad de Córdoba

El presente trabajo titulado “Análisis del Estrés Laboral en una PyME del sector de la Construcción de la ciudad de Córdoba” tiene por objetivo analizar los diferentes factores y condiciones laborales que generan estrés en la empresa analizada, como así también los grados de estrés del personal, en función de los síntomas que presentan. La modalidad utilizada fue la intervención profesional sobre una unidad estratégica de negocios de la empresa EE S.A. que brinda servicios para Aguas Cordobesas. El relevamiento de los datos se llevó a cabo a través de entrevistas y cuestionarios. Estos últimos se realizaron sobre una población de 30 personas que ocupan diferentes puestos de trabajo a lo largo de la estructura de la unidad de negocio. Para realizar el marco teórico fueron consultados diferentes autores, trabajos académicos internacionales, y profesionales que estudian y se dedican a la problemática en cuestión. Con el análisis de los datos relevados se identificaron aquellos factores que representan un mayor grado de peligrosidad en la generación del estrés laboral, como así también los síntomas más frecuentes entre los trabajadores encuestados. Finalmente, se pudo determinar la presencia de estrés en un nivel leve y moderado en la unidad analizada. En función a los síntomas presentes se concluyó que en general los trabajadores tienen un grado de estrés 2 y 3, en una escala del 1 al 6.Fil: Longhi, Yuliana Mailén. Universidad Nacional de Córdoba. Facultad de Ciencias Económica; Argentina.Fil: Barembaum, Mariel. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina

Pax2 and Pea3 synergize to activate a novel regulatory enhancer for spalt4 in the developing ear

The transcription factor spalt4 is a key early-response gene in otic placode induction. Here, we characterize the cis-regulatory regions of spalt4 responsible for activation of its expression in the developing otic placode and report the isolation of a novel core enhancer. Identification and mutational analysis of putative transcription factor binding sites reveal that Pea3, a downstream effector of FGF signaling, and Pax2 directly activate spalt4 during ear development. Morpholino-mediated knock-down of each factor reduces or eliminates reporter expression. In contrast, combined over-expression of Pea3 and Pax2 drives ectopic reporter expression, suggesting that they function synergistically. These studies expand the gene regulatory network underlying early otic development by identifying direct inputs that mediate spalt4 expression