The kinase activity of PKR represses inflammasome activity

The protein kinase R (PKR) functions in the antiviral response by controlling protein translation and inflammatory cell signaling pathways. We generated a transgenic, knock-in mouse in which the endogenous PKR is expressed with a point mutation that ablates its kinase activity. This novel animal allows us to probe the kinase-dependent and -independent functions of PKR. We used this animal together with a previously generated transgenic mouse that is ablated for PKR expression to determine the role of PKR in regulating the activity of the cryopyrin inflammasome. Our data demonstrate that, in contradiction to earlier reports, PKR represses cryopyrin inflammasome activity. We demonstrate that this control is mediated through the established function of PKR to inhibit protein translation of constituents of the inflammasome to prevent initial priming during innate immune signaling. These findings identify an important role for PKR to dampen inflammation during the innate immune response and caution against the previously proposed therapeutic strategy to inhibit PKR to treat inflammation.     

A quantitative method for assessing stages of the rat estrous cycle

The impact of gender and/or hormone variations on a wide variety of neural functions makes the choice between studying males or females (or both) of a given species difficult. Although female rats are widely used experimentally, few studies control for the stage of estrus. More detailed information about how to distinguish the various stages of the estrous cycle is needed. For the present study, vaginal smears were obtained once a day and stained using an adaptation of the Papanicolaou (PAP) procedure. Images are provided of unstained “wet” samples and the corresponding PAP stained smears illustrating the cellular profile for each stage of the cycle as well as post-ovariectomy. The different cell populations across the cycle were quantified and ratios determined to show trends between the predominant and other cell types in each stage of the estrous cycle. Both stained and unstained images and cell quantification data provide valuable guidelines for distinguishing the stages of the estrous cycle.     

Note Sui Grani a Spighe Ramificate

Resumé

Chez les Blés branchus de l'espèce «turgidum» (Triticum turgidum compositum), il existe des sortes à thermostade plutôt froid (Blés d'hiver ou de semi-hiver) et des sortes à thermostade chaud, tièe ou «indifférent» (Blés de printemps).

Les Blés branchus de l'espèce «turgidum» apparaissent comme étant des plantes à photostade de jour long.

La plus ou moins grande rapidité de l'accomplissement du photostade, par rapport à la rapidité de l'assimilation des matières plastiques, détermine la structure, — non ramifiée ou ramifiée — de l'épi.     

The role of survivin in angiogenesis during zebrafish embryonic development

Background  

Survivin is the smallest member of the inhibitor of apoptosis (IAP) gene family. Recently, the zebrafish survivin-1 gene has been cloned, showing remarkable sequence identity and similarity over the BIR domain compared with human and mouse survivin gene. Here we investigated the role of survivin in angiogenesis during zebrafish development. Morpholinos (MOs) targeting the 5' untranslated region (UTR) (Sur_UTR) and sequences flanking the initiation codon (Sur_ATG) of zebrafish survivin-1 gene were injected into embryos at 1–4 cell stage. Vasculature was examined by microangiography and GFP expression in Tg(fli1:EGFP) ^y1 embryos. Results: In embryos co-injected with Sur_UTR and Sur_ATG-MOs, vasculogenesis was intact but angiogenesis was markedly perturbed, especially in the inter-segmental vessels (ISV) and dorsal longitudinal anastomotic vessels (DLAV) of the trunk, the inner optic circle and optic veins of developing eyes and the sub-intestinal vessels. Apoptosis was increased, as shown by TUNEL staining and increase in caspase-3 activity. Efficacy of Sur_UTR and Sur_ATG-MOs was demonstrated by translation inhibition of co-injected 5'UTR survivin:GFP plasmids. The phenotypes could be recapitulated by splice-site MO targeting the exon2-intron junction of survivin gene and rescued by survivin mRNA. Injection of human vascular endothelial growth factor (VEGF) protein induced ectopic angiogenesis and increased survivin expression, whereas treatment with a VEGF receptor inhibitor markedly reduced angiogenesis and suppressed survivin expression. Conclusion: Survivin is involved in angiogenesis during zebrafish development and may be under VEGF regulation.     

Fruit structure and systematics of Monimiaceae s.s. (Laurales)

Fruit structure (anatomy) was studied in 27 species of 15 genera of Monimiaceae s.s. Almost all have apocarpous gynoecia, with the carpels more or less surrounded by a floral cup. The fruitlets are presented on the opened floral cup, which, depending on its pre‐ and post‐floral development, differentially contributes to the attractive part of the mature fruit. Morphologically similar fruits may differ conspicuously in anatomical structure. Based on anatomical characters two different fruit forms were found: drupe(let)s (with compact sclerenchymatic endocarp forming a stone: putamen) and berry(let)s (with parenchymatic endocarp, and mesocarp parenchyma containing isolated sclereid nests). Four types of drupelets differing by the endocarp structure were tentatively distinguished: (1) the Monimia‐type has a many‐cell‐layered putamen of large isodiametric sclereids, interrupted on the ventral side by few radial rows of small sclereids; (2) the Hortonia‐type has a few‐cell‐layered putamen of isodiametric, especially thick‐walled sclereids – it may be composed of two lateral halves, i.e. with the sclerenchyma partially interrupted on the ventral and dorsal sides (but without rows of small sclereids); (3) the Mollinedia‐type has a few‐cell‐layered putamen, with more or less radially elongate sclereids with wavy cell walls; and (4) the Hedycarya‐type has a one‐cell‐layered putamen of pronouncedly radially elongate sclereids with wavy cell walls. Drupelets of some taxa with a single‐cell‐layered endocarp with only weakly thickened cell walls may represent a transition from drupelets to berrylets. The fruit structure supports three major clades recognized earlier by morphological studies and by molecular phylogenetic analyses: (1) Monimioideae (Monimia‐type drupelets), (2) Hortonieae of Mollinedioideae (Hortonia‐type drupelets), and (3) the remainder of Mollinedioideae (Hedycarya‐ and Mollinedia‐types) and berrylets. Fruit structure also supports the close relationship of Monimiaceae and Lauraceae. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 153 , 265–285.     

Gene Cloning and Biochemical Characterization of an Alcohol Dehydrogenase from Euglena gracilis1

ABSTRACT. Euglena gracilis is a freshwater free‐living organism able to grow with ethanol as carbon source; to facilitate this metabolism several alcohol dehydrogenase (ADH) activities have been detected. We report the gene cloning, over‐expression, and biochemical characterization of a medium‐chain NAD⁺‐dependent ADH from E. gracilis (EgADH). The enzyme's amino acid sequence displayed the highest percentages of similarity and identity with ADHs of bacteria and fungi. In the predicted three‐dimensional model, all the residues involved in Zn²⁺, cofactor, and substrate binding were conserved. A conventional signal peptide for import into mitochondria could not be clearly identified. The protein of 37 kDa was over‐expressed, purified to homogeneity, and kinetically characterized. The enzyme's optimal pH was 7.0 for ethanol oxidation displaying a V_m of 11.7±3.6 U/mg protein and a K_m of 3.2±0.7 mM for this substrate. Isopropanol and isopentanol were also utilized, although with less efficiency. It showed specificity for NAD⁺ with a K_m value of 0.39±0.1 mM and Mg²⁺ or Zn²⁺ were essential for activity. The recombinant EgADH reported here may help to elucidate the roles that different ADHs have on the metabolism of short‐ and long‐chain alcohols in this microorganism.