Apontic regulates somatic stem cell numbers in Drosophila testes

BACKGROUND: Microenvironments called niches maintain resident stem cell populations by balancing self-renewal with differentiation, but the genetic regulation of this process is unclear. The niche of the Drosophila testis is well-characterized and genetically tractable, making it ideal for investigating the molecular regulation of stem cell biology. The JAK/STAT pathway, activated by signals from a niche component called the hub, maintains both germline and somatic stem cells. RESULTS: This study investigated the molecular regulation of the JAK/STAT pathway in the stem cells of the Drosophila testis. We determined that the transcriptional regulator Apontic (Apt) acts in the somatic (cyst) stem cells (CySCs) to balance differentiation and maintenance. We found Apt functions as a negative feedback inhibitor of STAT activity, which enables cyst cell maturation. Simultaneous loss of the STAT regulators apt and Socs36E, or the Stat92E-targeting microRNA miR-279, expanded the somatic stem cell-like population. CONCLUSIONS: Genetic analysis revealed that a conserved genetic regulatory network limits JAK/STAT activity in the somatic stem cells of Drosophila testis. In these cells, we determined JAK/STAT signaling promotes apt expression. Then, Apt functions through Socs36E and miR-279 to attenuate pathway activation, which is required for timely CySC differentiation. We propose that Apt acts as a core component of a STAT-regulatory circuit to prevent stem cell overpopulation and allow stem cell maturation

Ultrasound-Guided Microinjection into the Mouse Forebrain In Utero at E9.5

In utero survival surgery in mice permits the molecular manipulation of gene expression during development. However, because the uterine wall is opaque during early embryogenesis, the ability to target specific parts of the embryo for microinjection is greatly limited. Fortunately, high-frequency ultrasound imaging permits the generation of images that can be used in real time to guide a microinjection needle into the embryonic region of interest. Here we describe the use of such imaging to guide the injection of retroviral vectors into the ventricular system of the mouse forebrain at embryonic day (E) 9.5. This method uses a laparotomy to permit access to the uterine horns, and a specially designed plate that permits host embryos to be bathed in saline while they are imaged and injected. Successful surgeries often result in most or all of the injected embryos surviving to any subsequent time point of interest (embryonically or postnatally). The principles described here can be used with slight modifications to perform injections into the amnionic fluid of E8.5 embryos (thereby permitting infection along the anterior posterior extent of the neural tube, which has not yet closed), or into the ventricular system of the brain at E10.5/11.5. Furthermore, at mid-neurogenic ages (~E13.5), ultrasound imaging can be used direct injection into specific brain regions for viral infection or cell transplantation. The use of ultrasound imaging to guide in utero injections in mice is a very powerful technique that permits the molecular and cellular manipulation of mouse embryos in ways that would otherwise be exceptionally difficult if not impossible

Fibroblast growth factor receptor signaling promotes radial glial identity and interacts with Notch1 signaling in telencephalic progenitors

The Notch and fibroblast growth factor (FGF) pathways both regulate cell fate specification during mammalian neural development. We have shown previously that Notch1 activation in the murine forebrain promotes radial glial identity. This result, together with recent evidence that radial glia can be progenitors, suggested that Notch1 signaling might promote progenitor and radial glial character simultaneously. Consistent with this idea, we found that in addition to promoting radial glial character in vivo, activated Notch 1 (ActN1) increased the frequency of embryonic day 14.5 (E14.5) ganglionic eminence (GE) progenitors that grew into neurospheres in FGF2. Constitutive activation of C-promoter binding factor (CBF1), a Notch pathway effector, also increased neurosphere frequency in FGF2, suggesting that the effect of Notch1 on FGF responsiveness is mediated by CBF1. The observation that ActN1 promoted FGF responsiveness in telencephalic progenitors prompted us to examine the effect of FGF pathway activation in vivo. We focused on FGFR2 because it is expressed in radial glia in the GEs where ActN1 increases FGF2 neurosphere frequency, but not in the septum where it does not. Like ActN1, activated FGFR2 (ActFGFR2) promoted radial glial character in vivo. However, unlike ActN1, ActFGFR2 did not enhance neurosphere frequency at E14.5. Additional analysis demonstrated that, unexpectedly, neither ActFGFR2 nor ActFGFR1 could replace the need for ligand in promoting neurosphere proliferation. This study suggests that telencephalic progenitors with radial glial morphology are maintained by interactions between the Notch and FGF pathways, and that the mechanisms by which FGF signaling promotes radial glial character in vivo and progenitor proliferation in vitro can be uncoupled

Insertional mutagenesis in zebrafish using a pseudotyped retroviral vector

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 1997.Includes bibliographical references (leaves 155-158).by Nicholas R. Gaiano.Ph.D

Cost of Bordetella pertussis illness in tertiary hospitals in Argentina

La Comisión Nacional de Inmunizaciones y el ProNaCEI (Programa Nacional de Control de Enfermedades Inmunoprevenibles) actualizaron la política de vacunación por Bordetella pertussis (BP) a partir del año 2009 con el objetivo de optimizar el control de esta enfermedad, de acuerdo con las recomendaciones internacionales. Para evaluar el impacto económico de esta nueva política de vacunación resulta necesario conocer inicialmente el costo que implica para el sistema de salud un niño internado o ambulatorio con infección por BP. El objetivo de este estudio fue describir el perfl de costos en niños internados o tratados ambulatoriamente, con infección confrmada por laboratorio de BP en tres hospitales de la Argentina. Estudio prospectivo de costo de la enfermedad durante el período diciembre de 2010 a marzo de 2012. Resultados. El costo total para toda la cohorte fue de 1 170 663,32 pesos (236 497,64 dólares); los costos médicos directos, de 1 124 052,31 pesos (227 081,27 dólares); los costos indirectos y gastos de bolsillo, de 46611 pesos (9 416,36 dólares), lo que permite inferir un costo total promedio por paciente de 10 546,52 pesos (IC 95% 9009 a 13 840) (2130,60 dólares, IC 95% 1820 a 2795), costos médicos directos por paciente de 10 126,6 pesos (IC 95% 8607 a 13 171) (2045,77 dólares, IC 95%1738 a 2660) y costos indirectos más de bolsillo (viajes y extras) de 419,92 pesos (IC 95% 344,7 a 565,3), (84 dólares, IC 95% 69 a 115). Conclusión. El costo de un caso confrmado hospitalizado por BP es 10 546,52 pesos (IC 95% 9009 a 13 840) (2130,60 dólares, IC 95% 1820 a 2795). Los costos directos no médicos y costos indirectos constituyen el 4% del total, lo que corresponde a 419,91 pesos por familia (84 dólares, IC 95% 69 a 115), un 8% del salario promedio.Fil: Gentile, Angela. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "ricardo Gutierrez"; ArgentinaFil: Salgueiro, Ana L.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "ricardo Gutierrez"; ArgentinaFil: Garcia Bournissen, Facundo. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "r. Gutierrez". Servicio de Parasitología y Chagas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Romanin, Viviana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "ricardo Gutierrez"; ArgentinaFil: Bulgheroni, Sonia. Hospital Materno Infantil de San Isidro "Dr. Gianantonio"; ArgentinaFil: Gaiano, Alejandra. Hospital Materno Infantil de San Isidro "Dr. Gianantonio"; ArgentinaFil: Benegas, Liliana. Hospital de Niños "Víctor J. Vilela"; ArgentinaFil: Uboldi, Andrea. Hospital de Niños "Víctor J. Vilela"; ArgentinaFil: Giglio, Norberto. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "ricardo Gutierrez"; Argentin

Ultrasound-guided in utero injections allow studies of the development and function of the eye

Ultrasound-guided in utero injections into the brain of murine embryos has been shown to facilitate gene delivery. We investigated whether these methods would allow gene transfer into ocular structures. Gene transfer using retroviral vectors or electroporation was found to be quite effective. We determined the window of time, as well as compared several strains of mice, that yield a high degree of survival and successful gene transfer. Several retroviral constructs were tested for expression and coexpresssion of two genes in retinal cell types. In addition, a retroviral vector was engineered to give cone photoreceptor-enriched expression, and a retroviral vector was demonstrated to provide RNAi-mediated loss-of-function. These methods enable access to early ocular structures and provide a more rapid method of assessment of gene and promoter function than possible using genetically engineered mice

Caracterização física e química da polpa de diferentes variedades de abacate visando o potencial para extração de óleo

The aim of this study was to evaluate the physicochemical properties of avocado pulp of four different varieties (Avocado, Guatemala, Dickinson, and Butter pear) and to identify which has the greatest potential for oil extraction. Fresh avocado pulp was characterized by moisture, protein, fat, ash, carbohydrates and energy contents were determined. The carotenoids and chlorophyll contents were determined by the organic solvent extraction method. The results showed significant differences in the composition of the fruit when varieties are compared. However, the striking feature in all varieties is high lipid content; Avocado and Dickinson are the most suitable varieties for oil extraction, taking into account moisture content and the levels of lipids in the pulp. Moreover, it could be said that the variety Dickinson is the most affected by the parameters evaluated in terms of overall quality. Chlorophyll and carotenoids, fat-soluble pigments, showed a negative correlation with respect to lipids since it could be related to its function in the fruit. The varieties Avocado and Dickinson are an alternative to oil extraction having great commercial potential to be exploited thus avoiding waste and increasing farmers income