Down-regulation of inhibitor of apoptosis levels provides competence for steroid-triggered cell death

A pulse of the steroid hormone ecdysone triggers the destruction of larval salivary glands during Drosophila metamorphosis through a transcriptional cascade that converges on reaper (rpr) and head involution defective (hid) induction, resulting in caspase activation and cell death. We identify the CREB binding protein (CBP) transcriptional cofactor as essential for salivary gland cell death. We show that CBP acts 1 d before the onset of metamorphosis in apparent response to a mid-third instar ecdysone pulse, when CBP is necessary and sufficient for down-regulation of the Drosophila inhibitor of apoptosis 1 (DIAP1). It is only after DIAP1 levels are reduced that salivary glands become competent to die through rpr/hid-mediated cell death. Before this time, high levels of DIAP1 block salivary gland cell death, even in the presence of ectopic rpr expression. This study shows that naturally occurring changes in inhibitor of apoptosis levels can be critical for regulating cell death during development. It also provides a molecular mechanism for the acquisition of competence in steroid signaling pathways

Comunidades de Parásitos Metazoos en Ocho Especies de Peces del Género Haemulon (FAM: Haemulidae) del Golfo de Cariaco, Venezuela

Se examinaron ejemplares de ocho especies de peces pertenecientes al género Haemulon (Fam: Haemulidae) del Golfo de Cariaco, y se encontró una comunidad de 19 especies de parásitos. La comparación de los promedios de abundancia infrapoblacional de las especies de helmintos compartidas indicó que H. steindachneri tenía una carga parasitaria de Lasiotocus longovatus y Genolopa ampullacea significativamente más grande que las otras siete especies de hospederos. De las tres especies compartidas de helmintos, las especies dominantes L. longovatus y Brachadena pyriformis, y la codominante G. ampullacea, aparentaron ser conservadas por todas las especies. No existió diferencias significativas en la infrapoblación de parásitos entre los sexos de los hospederos. La diversidad comunitaria tiende a aumentar con el tamaño en H. steindachneri y H. aurolineatum y sus parásitos fueron relativamente más abundantes en comparación con las otras seis especies en el área. El índice de Jaccard de similaridad demostró una relación constante entre L. longovatus, G. ampullacea y Diplangus paxillu

Studies in RF power communication, SAR, and temperature elevation in wireless implantable neural interfaces

Implantable neural interfaces are designed to provide a high spatial and temporal precision control signal implementing high degree of freedom real-time prosthetic systems. The development of a Radio Frequency (RF) wireless neural interface has the potential to expand the number of applications as well as extend the robustness and longevity compared to wired neural interfaces. However, it is well known that RF signal is absorbed by the body and can result in tissue heating. In this work, numerical studies with analytical validations are performed to provide an assessment of power, heating and specific absorption rate (SAR) associated with the wireless RF transmitting within the human head. The receiving antenna on the neural interface is designed with different geometries and modeled at a range of implanted depths within the brain in order to estimate the maximum receiving power without violating SAR and tissue temperature elevation safety regulations. Based on the size of the designed antenna, sets of frequencies between 1 GHz to 4 GHz have been investigated. As expected the simulations demonstrate that longer receiving antennas (dipole) and lower working frequencies result in greater power availability prior to violating SAR regulations. For a 15 mm dipole antenna operating at 1.24 GHz on the surface of the brain, 730 uW of power could be harvested at the Federal Communications Commission (FCC) SAR violation limit. At approximately 5 cm inside the head, this same antenna would receive 190 uW of power prior to violating SAR regulations. Finally, the 3-D bio-heat simulation results show that for all evaluated antennas and frequency combinations we reach FCC SAR limits well before 1 °C. It is clear that powering neural interfaces via RF is possible, but ultra-low power circuit designs combined with advanced simulation will be required to develop a functional antenna that meets all system requirements. © 2013 Zhao et al

Implantable Neural Probes for Brain-Machine Interfaces - Current Developments and Future Prospects

A Brain-Machine interface (BMI) allows for direct communication between the brain and machines. Neural probes for recording neural signals are among the essential components of a BMI system. In this report, we review research regarding implantable neural probes and their applications to BMIs. We first discuss conventional neural probes such as the tetrode, Utah array, Michigan probe, and electroencephalography (ECoG), following which we cover advancements in next-generation neural probes. These next-generation probes are associated with improvements in electrical properties, mechanical durability, biocompatibility, and offer a high degree of freedom in practical settings. Specifically, we focus on three key topics: (1) novel implantable neural probes that decrease the level of invasiveness without sacrificing performance, (2) multi-modal neural probes that measure both electrical and optical signals, (3) and neural probes developed using advanced materials. Because safety and precision are critical for practical applications of BMI systems, future studies should aim to enhance these properties when developing next-generation neural probes

HALLAZGO DE Echinochasmus macrocaudatus DITRICH et al. 1996 (TREMATODA: ECHINOSTOMATIDAE) EN EL CHICUACO CUELLO GRIS, Butorides striatus, EN VENEZUELA

Este estudio redescribe a Echinochasmus macrocaudatus Ditrich, Scholz y Vargas-Vásquez 1996, del intestino delgado del ave Butorides striatus de la localidad de Chirgua, estado Sucre. Venezuela. Este trabajo informa por primera vez la ocurrencia del trematodo en un hospedero natural desde que fue descrito en 1996 de los hospedros experimentales, Gallus gallus f. domestica y Anas platyrhynchos f. domestica. El trabajo provee información relacionada con su nuevo hospedero definitivo natural y la nueva distribución geográfica de este parásito.   Palabras clave: Trematoda, Echinochasmus, Aves, Butorides striatus, Distribución geográfica, Venezuela.   ABSTRACT This research redescribes Echinochasmus macrocaudatus (Ditrich, Scholz and Vargas-Vásquez 1996), found in the small intestine of a bird Butorides striatus from Chirgua, a small village in the state of Sucre, Venezuela. In this study, the presence of the trematode in a natural host is reported for the first time ever since it was described in 1996 in experimental hosts Gallus gallus f. domentica and Anas platyrhynchos f. domestica. This study provides information about the parasite´s new geographical distribution and its new natural final host.   Key words: Trematoda, Echinochasmus, Birds, Butorides striatus, Geographical distribution, Venezuela

RNA localization in development

Cytoplasmic RNA localization is an evolutionarily ancient mechanism for producing cellular asymmetries. This review considers RNA localization in the context of animal development. Both mRNAs and non-protein-coding RNAs are localized in Drosophila, Xenopus, ascidian, zebrafish, and echinoderm oocytes and embryos, as well as in a variety of developing and differentiated polarized cells from yeast to mammals. Mechanisms used to transport and anchor RNAs in the cytoplasm include vectorial transport out of the nucleus, directed cytoplasmic transport in association with the cytoskeleton, and local entrapment at particular cytoplasmic sites. The majority of localized RNAs are targeted to particular cytoplasmic regions by cis-acting RNA elements; in mRNAs these are almost always in the 3'-untranslated region (UTR). A variety of trans-acting factors—many of them RNA-binding proteins—function in localization. Developmental functions of RNA localization have been defined in Xenopus, Drosophila, and Saccharomyces cerevisiae. In Drosophila, localized RNAs program the antero-posterior and dorso-ventral axes of the oocyte and embryo. In Xenopus, localized RNAs may function in mesoderm induction as well as in dorso-ventral axis specification. Localized RNAs also program asymmetric cell fates during Drosophila neurogenesis and yeast budding

Distribución espacial y descriptores comunitarios de ectoparásitos en branquias de cojinua, caranx ruber (bloch, 1793) de Santa Cruz, estado Sucre, Venezuela / The spatial distribution and community descriptors of ectoparasites in gills of bar jack, caranx ruber (bloch, 1793) from santa cruz, Sucre state, Venezuela

ResumenSe analizó la distribución espacial y los descriptores comunitarios (prevalencia, densidad absoluta, densidadrelativa e índice de infección) de ectoparásitos en branquias de la cojinúa carbonera, Caranx ruber Bloch, 1793recolectados en Santa Cruz, estado Sucre, Venezuela, desde mayo de 2005 hasta abril de 2006. Se determinóel índice de dispersión (ID) y el índice de Green (IG) de los ectoparásitos en 155 ejemplares de C. ruber. Seregistraron tres monogéneos (Protomicrocotyle mirabilis, Allopyragraphorus incomparabilis, Pseudomazocraessp.), dos copépodos (Lernanthrophus kroyeri, Caligus spp.) y un isópodo (Cymothoa oestrum). Los parásitosmonogéneos mostraron preferencia por el arco branquial 1 y Pseudomazocraes sp. prefirió el lado derechodel pez. Los monogéneos se consideraron especies comunes; P. mirabilis se consideró además especie centralmientras que los copépodos e isópodo resultaron especies secundarias. Los parásitos presentaron el típico patrónde distribución agregado (ID > 1; IG +). Se observó una correlación significativa entre los valores de densidadabsoluta de P. mirabilis (rs = 0,778; p < 0,05) y de Pseudomazocraes sp. (rs = 0,731; p < 0,05) con la talla de losejemplares del hospedero, C. ruber. Las comunidades de monogeneos presentaron fluctuaciones estacionales. Elmayor número de especies de parásitos en un hospedero determinado, estuvo relacionado con el medio ambientemás diverso de la localidad.Palabras clave: Microhábitat, peces marinos, ectoparásito, Monogenea, Isopoda, Copepoda.ABSTRACTThe spatial distribution and community descriptors (prevalence, absolute density, relative density andinfection index) of the ectoparasites in gills of the bar jack Caranx ruber Bloch, 1793 from Santa Cruz, Sucrestate, Venezuela, were evaluated from May 2005 to April 2006. The Dispersion Index (DI), and Green Index (GI)of ecoparasites from 155 specimens of C. rubber is described. There were three monogeneans (Protomicrocotylemirabilis, Allopyragraphorus incomparabilis, Pseudomazocraes s p.), t wo c opepods (Lernanthrophus kroyeri,Caligus spp.), and one isopod (Cymothoa oestrum). The monogenean parasites showed preference for gill arch Iand Pseudomazocraes sp. preferred the right side of the fish. The monogeneans were considered common specieswhile P. mirabilis was also considered a central species, and the copepods and isopod were considered as secondaryspecies. The parasites showed a typical aggregate pattern of distribution (ID > 1; IG +). There was a significantcorrelation between the values of absolute density of P. mirabilis (rs = 0.778, p < 0.05) and Pseudomazocraes sp.(rs = 0.731, p <0.05) with the size of the host, C. ruber. The parasite communities showed seasonal fluctuation.The highest number of parasite species in a given host was related to the higher diversity of the local environment.Key words: Microhabitat, marine fish, ectoparasite, Monogenea, Copepoda, Isopoda

Ultra-thin biocompatible implantable chip for bidirectional communication with peripheral nerves

To realize optimal recording and stimulation of peripheral nerve cells, a CMOS chip is made with a multitude of electrodes which can be individually addressed in order to select after implantation the 16 best positioned electrodes. Since the Foreign Body Reaction should be minimal for optimum electrode-nerve contact, the CMOS chip is thinned down to 35um and fully packaged resulting in a 75um thin encapsulated chip. The chip is embedded in a biocompatible stack consisting of polymers and inorganic diffusion barriers deposited using atomic layer deposition (ALD). A biocompatible metallization is realized using gold and platinum sandwiched between polymers and ALD layers for flexible interconnects, and iridium oxide (IrOx) is selected as electrode material for optimal charge injection during stimulation. After this dedicated packaging based on the FITEP technology platform (Flexible Implantable Thin Electronic Package), the CMOS chip is still fully functional, which was tested dry (in air) as well as during submersion in saline. The form factor of the packaged chip is optimized for intra-fascicular implantation with minimum tissue damage. First acute in vivo stimulation tests proved that the stimulation capabilities of the IrOx electrodes are very good