Changes in the kinase activity of the insulin receptor account for an increased insulin sensitivity of mammary gland in late pregnancy

Copyright (1998) The Endocrine Society .The paper can be found at the following URL on the website http://endo.endojournals.org

The T=1 capsid protein of Penicillium chrysogenum virus is formed by a repeated helix-rich core indicative of gene duplication

et al.Penicillium chrysogenum virus (PcV), a member of the Chrysoviridae family, is a double-stranded RNA (dsRNA) fungal virus with a multipartite genome, with each RNA molecule encapsidated in a separate particle. Chrysoviruses lack an extracellular route and are transmitted during sporogenesis and cell fusion. The PcV capsid, based on a T=1 lattice containing 60 subunits of the 982-amino-acid capsid protein, remains structurally undisturbed throughout the viral cycle, participates in genome metabolism, and isolates the virus genome from host defense mechanisms. Using three-dimensional cryoelectron microscopy, we determined the structure of the PcV virion at 8.0 Å resolution. The capsid protein has a high content of rod-like densities characteristic of α-helices, forming a repeated α-helical core indicative of gene duplication. Whereas the PcV capsid protein has two motifs with the same fold, most dsRNA virus capsid subunits consist of dimers of a single protein with similar folds. The spatial arrangement of the α-helical core resembles that found in the capsid protein of the L-A virus, a fungal totivirus with an undivided genome, suggesting a conserved basic fold. The encapsidated genome is organized in concentric shells; whereas the inner dsRNA shells are well defined, the outermost layer is dense due to numerous interactions with the inner capsid surface, specifically, six interacting areas per monomer. The outermost genome layer is arranged in an icosahedral cage, sufficiently well ordered to allow for modeling of an A-form dsRNA. The genome ordering might constitute a framework for dsRNA transcription at the capsid interior and/or have a structural role for capsid stability. Copyright © 2010, American Society for Microbiology. All Rights Reserved.This work was supported by grants from the Spanish Ministry of Science and Innovation (BFU 2008-02328/BMC and S-0505-Mat-0238 to J.L.C. and BIO2008-02361 to J.R.C.) and the NIH Intramural Research Program with support from the Center for Information Technology.Peer Reviewe

Trapping and patterning of biological objects using photovoltaic tweezers

Photovoltaic tweezers are a recently proposed technique for manipulation and patterning of micro- and nano-objects. It is based in the dielectrophoretic forces associated to the electric fields induced by illumination of certain ferroelectrics due to the bulk photovoltaic effect. The technique has been applied to the patterning of dielectric and metal micro- and nano-particles. In this work, we report the use of photovoltaic tweezers to pattern biological objects on LiNbO3:Fe. Specifically, spores and pollen grains and their nanometric fragments have been trapped and patterned. 1D and 2D arrangements have been achieved by deposition in air or from a hexane suspension. The quality of patterns obtained with nanometric fragments is even better than previous results using photovoltaic tweezers with inorganic micro- and nano-particles. In fact, 1D patterns with a period of 2 μm, almost half of the minimum reported period achieved with photovoltaic tweezers, have been obtained with pollen fragmentsThis work was supported by Spanish projects MAT2011-28379-C03 and MAT2014-57704-C0

The Structure of a Biologically Active Influenza Virus Ribonucleoprotein Complex

The influenza viruses contain a segmented, single-stranded RNA genome of negative polarity. Each RNA segment is encapsidated by the nucleoprotein and the polymerase complex into ribonucleoprotein particles (RNPs), which are responsible for virus transcription and replication. Despite their importance, information about the structure of these RNPs is scarce. We have determined the three-dimensional structure of a biologically active recombinant RNP by cryo-electron microscopy. The structure shows a nonameric nucleoprotein ring (at 12 Å resolution) with two monomers connected to the polymerase complex (at 18 Å resolution). Docking the atomic structures of the nucleoprotein and polymerase domains, as well as mutational analyses, has allowed us to define the interactions between the functional elements of the RNP and to propose the location of the viral RNA. Our results provide the first model for a functional negative-stranded RNA virus ribonucleoprotein complex. The structure reported here will serve as a framework to generate a quasi-atomic model of the molecular machine responsible for viral RNA synthesis and to test new models for virus RNA replication and transcription

Ultrastructural and functional analyses of recombinant influenza virus ribonucleoproteins suggest dimerization of nucleoprotein during virus amplification

8 pages, 7 figures.-- PMID: 10590102 [PubMed].-- PMCID: PMC111524.Full-text version available Open Access at PebMed Central: http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=10590102Influenza virus ribonucleoproteins (RNPs) were reconstituted in vivo from cloned cDNAs expressing the three polymerase subunits, the nucleoprotein (NP), and short template RNAs. The structure of purified RNPs was studied by electron microscopy and image processing. Circular and elliptic structures were obtained in which the NP and the polymerase complex could be defined. Comparison of the structure of RNPs of various lengths indicated that each NP monomer interacts with approximately 24 nucleotides. The analysis of the amplification of RNPs with different lengths showed that those with the highest replication efficiency contained an even number of NP monomers, suggesting that the NP is incorporated as dimers into newly synthesized RNPs.J. Ortega was a fellow of Instituto de Estudios Turolenses. This work was supported by Programa Sectorial de Promoción General del Conocimiento (grants PB97-1160 and PB96-0818).Peer reviewe

ObRa and ObRe are differentially expressed in adipose tissue in aged food-restricted rats: Effects on circulating soluble leptin receptor levels

Copyright (2005) The Endocrine Society .The paper can be found at the following URL on the website http://endo.endojournals.org

In Vivo insulin-dependent glucose uptake of specific tissues is decreased during aging of mature wistar rats

Copyright (1997) The Endocrine Society .The paper can be found at the following URL on the website http://endo.endojournals.org

Particle Patterning on Lithium Niobate waveguides via photovoltaic tweezers

Successful micro and nano-particle patterning on iron doped lithium niobate waveguides using photovoltaic fields is reported. This technique previously used in bulk crystals is here applied to waveguide configuration. Well defined particle patterns are obtained using two types of planar waveguides (by proton exchanged and swift heavy ion irradiation) and metallic and dielectric neutral particles. The use of waveguide configuration has allowed a reduction of the light exposure time until 3 s, two orders of magnitude smaller than typical values used in bulk

Individualization of Pinus radiata Canopy from 3D UAV Dense Point Clouds Using Color Vegetation Indices

The location of trees and the individualization of their canopies are important parameters to estimate diameter, height, and biomass, among other variables. The very high spatial resolution of UAV imagery supports these processes. A dense 3D point cloud is generated from RGB UAV images, which is used to obtain a digital elevation model (DEM). From this DEM, a canopy height model (CHM) is derived for individual tree identification. Although the results are satisfactory, the quality of this detection is reduced if the working area has a high density of vegetation. The objective of this study was to evaluate the use of color vegetation indices (CVI) in canopy individualization processes of Pinus radiata. UAV flights were carried out, and a 3D dense point cloud and an orthomosaic were obtained. Then, a CVI was applied to 3D point cloud to differentiate between vegetation and nonvegetation classes to obtain a DEM and a CHM. Subsequently, an automatic crown identification procedure was applied to the CHM. The results were evaluated by contrasting them with results of manual individual tree identification on the UAV orthomosaic and those obtained by applying a progressive triangulated irregular network to the 3D point cloud. The results obtained indicate that the color information of 3D point clouds is an alternative to support individualizing trees under conditions of high-density vegetation

Aging impairs the hepatic subcellular distribution of ChREBP in response to fasting/feeding in rats: Implications on hepatic steatosis

© 2015 Elsevier Inc. All rights reserved. Aging is associated with alterations of lipid metabolism and increased prevalence of non alcoholic hepatic steatosis.Nevertheless, themechanisms bywhich fat is accumulated in the liver during aging remain incompletely understood. In the present study, we investigated potential alterations that might contribute to the development of hepatic steatosis with aging. To this end, we analyzed the expression and the subcellular localization of key transcriptional factors involved in lipid metabolism such as ChREBP, Foxo1, Foxa2 and SREBP-1c in the liver of 3- and 24-month oldWistar rats. In addition, we studied the intracellular redistribution of ChREBP in response to fasting/refeeding transition. Old rats were characterized by hepatic steatosis, low serum ketone body levels and postprandial hyperinsulinemia. These observations were paralleled by the cytoplasmic localization and decreased expression of Foxa2, while ChREBP expression was markedly up-regulated and mainly localized in the nucleus. Consequently, the expression of lipogenic and β-oxidation genes was up-regulated or downregulated, respectively. Besides, the intracellular redistribution of ChREBP in response to fasting/refeeding transition was also impaired in old animals. Additionally, a negative correlation between serum ketone body levels and the nuclear localization of ChREBP was observed only in adult but not in old rats. Taken together, these data suggest that an age-related dysfunctional adaptation of ChREBP, in response to changes in the nutritional state, might contribute to the development of liver steatosis with aging.Junta de Comunidades de Castilla-La Mancha (JCCM), BFU2012- 39705-C03-01 from Ministerio de Ciencia e Innovación, and S2010/BMC2423 from Comunidad de Madrid, Spain. A.S. was supported by FPU predoctoral fellowship from Ministerio de Educación y Ciencia (MEC), Spain, and B.B. was supported by CONACyT predoctoral fellowship from México. The Centre of Molecular Biology “Severo Ochoa” is the recipient of institutional aid from the Ramón Areces FoundationPeer Reviewe