The embryonic genes Dkk3, Hoxd8, Hoxd9 and Tbx1 identify muscle types in a diet-independent and fiber-type unrelated way

<p>Abstract</p> <p>Background</p> <p>The mouse skeletal muscle is composed of four distinct fiber types that differ in contractile function, number of mitochondria and metabolism. Every muscle type has a specific composition and distribution of the four fiber types. To find novel genes involved in specifying muscle types, we used microarray analysis to compare the gastrocnemius with the quadriceps from mice fed a low fat diet (LFD) or high fat diet (HFD) for 8 weeks. Additional qPCR analysis were performed in the gastrocnemius, quadriceps and soleus muscle from mice fed an LFD or HFD for 20 weeks.</p> <p>Results</p> <p>In mice fed the 8-week LFD 162 genes were differentially expressed in the gastrocnemius <it>vs</it>. the quadriceps. Genes with the strongest differences in expression were markers for oxidative fiber types (e.g. <it>Tnni1</it>) and genes which are known to be involved in embryogenesis (<it>Dkk3</it>, <it>Hoxd8</it>,<it>Hoxd9 </it>and <it>Tbx1</it>). Also <it>Dkk2, Hoxa5, Hoxa10, Hoxc9, Hoxc10, Hoxc6 </it>and <it>Tbx15 </it>were detectably, but not differentially expressed in adult muscle tissue. Expression of differentially expressed genes was not influenced by an 8-week or 20-week HFD. Comparing gastrocnemius, quadriceps and soleus, expression of <it>Hoxd8 </it>and <it>Hoxd9 </it>was not related with expression of markers for the four different fiber types. We found that the expression of both <it>Hoxd8 </it>and <it>Hoxd9 </it>was much higher in the gastrocnemius than in the quadriceps or soleus, whereas the expression of <it>Dkk3 </it>was high in quadriceps, but low in both gastrocnemius and soleus. Finally, expression of <it>Tbx1 </it>was high in quadriceps, intermediate in soleus and low in gastrocnemius.</p> <p>Conclusions</p> <p>We found that genes from the Dkk family, Hox family and Tbx family are detectably expressed in adult mouse muscle. Interestingly, expression of <it>Dkk3</it>, <it>Hoxd8, Hoxd9 </it>and <it>Tbx1 </it>was highly different between gastrocnemius, quadriceps and soleus. In fact, every muscle type showed a unique combination of expression of these four genes which was not influenced by diet. Altogether, we conclude that genes important for embryogenesis identify mouse muscle types in a diet-independent and fiber type-unrelated manner.</p

Camera-onderzoek naar grondpredatoren en nestpredatie bij weidevogels in Skriezekrite Idzegea

Skriezekrite Idzegea is een belangrijk weidevogelgebied in het zuid-westen van Friesland met nog relatief hoge dichtheden weidevogels. Ondanks een groot aandeel weidevogelbeheer heeft het gebied vanaf 2015 te kampen gehad met een toegenomen predatiedruk waardoor de weidevogelstand is afgenomen en in het verleden behaalde positieve resultaten verloren zijn gegaan. De nestverliezen worden toegeschreven aan een toename van niet-bejaagbare martersoorten als hermelijn, bunzing en steenmarter. Om deze aanname te onderbouwen is met behulp van cameravallen getracht te achterhalen welke grondpredatoren binnen het gebied aanwezig zijn en in welke mate ze verantwoordelijk zijn voor nestpredatie. Daarnaast is gekeken naar de invloed van een nieuw type camera van het merk Browning op het broedresultaat van weidevogelnesten, omdat uitvoorgaand camerawerk naar voren kwam dat cameravallen van het veel gebruikte merk Reconyx vaak opgemerkt werden door nachtelijke zoogdieren. Een effect wat ongewenst is bij het monitoren van nesten. Bunzing en steenmarter werden vrijwel overal aangetroffen in tegenstelling tot hermelijn en wezel. Katten werden veruit het meest waargenomen. Vos bleek niet aanwezig. Dat o.a. Reconyx-cameravallen regelmatig opgemerkt worden door nachtelijke zoogdieren werd bevestigd. Voor de camera’s van het merk Browning die voor de nestmonitoring gebruikt zijn kon dit niet aangetoond worden. In totaal werden 93 nesten van kievit, grutto of scholekster gevolgd waarvan 46 met camera werden gevolgd en 47 als controlenest dienden om het effect van camera’s bij nesten te bepalen. Er was geen significant verschil tussen de broedresultaten van cameranesten en controlenesten. Nestpredatie was met 22,5% aanzienlijk lager dan voorgaande jaren. Door dit geringe verlies was de steekproefgrootte onvoldoende om vast te stellen in welke mate specifieke predatoren verantwoordelijk zijn. Er werd nestpredatie door bunzing, steenmarter en zwarte kraai vastgesteld. Daarnaast werd duidelijk dat het gebruik van nestcamera’s of nestmarkering in het algemeen risico’s met zich meebrengt doordat predatoren, in dit geval zwarte kraai, kunnen aanleren dat er voedsel verkrijgbaar is bij specifieke objecten

A monitor for Cellular Oxygen METabolism (COMET): monitoring tissue oxygenation at the mitochondrial level

After introduction of the protoporphyrin IX-triplet state lifetime technique as a new method to measure mitochondrial oxygen tension in vivo, the development of a clinical monitor was started. This monitor is the “COMET”, an acronym for Cellular Oxygen METabolism. The COMET is a non-invasive electrically powered optical device that allows measurements on the skin. The COMET is easy to transport, due to its lightweight and compact size. After 5-aminolevulinic acid application on the human skin, a biocompatible sensor enables detection of PpIX in the mitochondria. PpIX acts as a mitochondrially located oxygen-sensitive dye. Three measurement types are available in the touchscreen-integrated user interface, ‘Single’, ‘Interval’ and ‘Dynamic measurement’. COMET is currently used in several clinical studies in our institution. In this first description of the COMET device we show an incidental finding during neurosurgery. To treat persisting intraoperative hypertension a patient was administered clonidine, but due to rapid administration an initial phase of peripheral vasoconstriction occurred. Microvascular flow and velocity parameters measured with laser-doppler (O2C, LEA Medizintechnik) decreased by 44 and 16% respectively, but not the venous-capillary oxygen saturation. However, mitochondrial oxygen tension in the skin detected by COMET decreased from a steady state of 48 to 16 mmHg along with the decrease in flow and velocity. We conclude that COMET is ready for clinical application and we see the future for this bedside monitor on the intensive care, operating theater, and testing of mitochondrial effect of pharmaceuticals

RNA-guided complex from a bacterial immune system enhances target recognition through seed sequence interactions

Prokaryotes have evolved multiple versions of an RNA-guided adaptive immune system that targets foreign nucleic acids. In each case, transcripts derived from clustered regularly interspaced short palindromic repeats (CRISPRs) are thought to selectively target invading phage and plasmids in a sequence-specific process involving a variable cassette of CRISPR-associated (cas) genes. The CRISPR locus in Pseudomonas aeruginosa (PA14) includes four cas genes that are unique to and conserved in microorganisms harboring the Csy-type (CRISPR system yersinia) immune system. Here we show that the Csy proteins (Csy1-4) assemble into a 350 kDa ribonucleoprotein complex that facilitates target recognition by enhancing sequence-specific hybridization between the CRISPR RNA and complementary target sequences. Target recognition is enthalpically driven and localized to a "seed sequence" at the 5' end of the CRISPR RNA spacer. Structural analysis of the complex by small-angle X-ray scattering and single particle electron microscopy reveals a crescent-shaped particle that bears striking resemblance to the architecture of a large CRISPR-associated complex from Escherichia coli, termed Cascade. Although similarity between these two complexes is not evident at the sequence level, their unequal subunit stoichiometry and quaternary architecture reveal conserved structural features that may be common among diverse CRISPR-mediated defense systems

High Irritation and Removal Rates After Plate or Nail Fixation in Patients With Displaced Midshaft Clavicle Fractures

Background: Studies comparing plate with intramedullary nail fixation of displaced midshaft clavicle fractures show faster recovery in the plate group and implant-related complications in both groups after short-term followup (6 or 12 months). Knowledge of disability, complications, and removal rates beyond the first postoperative year will help surgeons in making a decision regarding optimal implant choice. However, comparative studies with followup beyond the first year or two are scarce. Questions/purposes: We asked: (1) Does plate fixation or intramedullary nail fixation for displaced midshaft clavicle fractures result in less disability? (2) Which type of fixation, plate or intramedullary, is more frequently associated with implant-related irritation and implant removal? (3) Is plate or intramedullary fixation associated with postoperative complications beyond the first postoperative year? Methods: Between January 2011 and August 2012, patients with displaced midshaft clavicle fractures were enrolled and randomized to plate or intramedullary nail fixation. A total of 58 patients with plate and 62 patients with intramedullary nails initially were enrolled. Minimum followup was 30 months (mean, 39 months; range, 30–51 months). Two patients (3%) with plate fixation and two patients (3%) with intramedullary nails were lost to followup. The Qui