Acyl chain composition determines cardiolipin clustering induced by mitochondrial creatine kinase binding to monolayers

It has been recently shown that mitochondrial creatine kinase (mtCK) organizes mitochondrial model membrane by modulating the state and fluidity of lipids and by promoting the formation of protein-cardiolipin clusters. This report shows, using Brewster angle microscopy, that such clustering is largely dependent on the acyl chain composition of phospholipids. Indeed, mtCK-cardiolipin domains were observed not only with unsaturated cardiolipins, but also with the cardiolipin precursor phosphatidylglycerol. On the other hand, in the case of saturated dimyristoylphosphatidylglycerol and tetramyristoylcardiolipin, mtCK was homogeneously distributed underneath the monolayer. However, an overall decrease in membrane fluidity was indicated by infrared spectroscopy as well as by extrinsic fluorescence spectroscopy using Laurdan as a fluorescent probe, both for tetramyristoylcardiolipin and bovine heart cardiolipin containing liposomes. The binding mechanism implicated the insertion of protein segments into monolayers, as evidenced from alternative current polarography, regardless of the chain unsaturation for the phosphatidylglycerols and cardiolipins tested.     

Resistive exercises, with or without whole body vibration, prevent vertebral marrow fat accumulation during 60 days of head-down tilt bed rest in men

Fat accumulates in the bone marrow of lumbar vertebrae with bed rest. Exercise with or without whole body vibration may counter this effect. Our objectives were to measure 1) the vertebral fat fraction (VFF) of men subjected to bed rest who performed resistive exercises with (RVE, n = 7) or without whole body vibration(RE, n = 8) or no exercise (CTR, n = 9) using three MRI techniques; and 2) changes in peripheral blood counts. Twenty-four healthy men (age: 20-45 yr) underwent -6° head-down tilt (HDT) bed rest for 60 days. MRI was performed using three techniques (fat saturation, proton spectroscopy, and in and out of phase) to measure the fat fraction of L(3), L(4), and/or L(5) at baseline, mid-HDT, and end-HDT. Erythrocytes and leukocytes were counted at HDT days 19, 33, 47, 54, and 60. The mean absolute VFF was increased in the CTR group at mid-HDT and end-HDT (+3.9 ± 1.3 and +3.6 ± 1.2%, respectively, both P < 0.05). The RE group had a smaller VFF change than the CTR group at mid-HDT (-0.9 ± 1.2 vs. +3.9 ± 1.3%, P < 0.05). The RVE group had a smaller VFF change than the CTR group at end-HDT (-2.6 ± 1.9 vs. +3.5 ± 1.2%, P < 0.05). Erythrocyte counts were increased in all groups at HDT day 19 and HDT day 33 and in the RE group at HDT day 54 (all P < 0.05). Bed rest for 60 days at -6° HDT increased lumbar VFF in men beyond natural involution. RVE and RE regimens effectively prevented VFF accumulation. Higher erythrocyte counts were not altered by RVE or RE. Whole body vibration, along with RE administered to people with prolonged immobility, may prevent fat accumulation in their bone marrow.     

Hybrid Access to Atria via the Guiraudon Universal Cardiac Introducer for Arrhythmia Ablation After Total Cavopulmonary Derivation

ABSTRACT: We report the first use of a new platform, the Guiraudon Universal Cardiac Introducer (GUCI), in humans for accessing the left atrium for catheter-based ablations in patients with resistant atrial arrhythmias after total cavopulmonary derivation. The GUCI was originally designed for intracardiac access for closed, beating instrumental intracardiac surgery.The patient was a 29-year-old man with problematic atrial arrhythmias resistant to antiarrhythmic drugs because of severe uncontrolled bradycardia and because his pacemaker was explanted for infection.The GUCI was attached to the left atrial appendage via an anterior left thoracotomy. The GUCI was modified to accommodate introduction and manipulation of multiple catheters. This allowed electrophysiologists to perform catheter-based exploration and ablation. A DDD pacemaker was implanted, with an atrial endocardial lead introduced via the GUCI cuff and a ventricular epicardial lead.Postoperative atrial arrhythmias were controlled using amiodarone and atrial pacing. At the 12-month follow-up, the patient was arrhythmia- and drug-free and returned to full employment.This new access offers an additional new alternative atrial access to treat resistant arrhythmia after total cavopulmonary derivation. The current state-of-the-art makes patient selection difficult and uncomfortable for the surgeons because of incomplete preoperative electrophysiological data, such as a return to the beginning of surgery for arrhythmia; however, more cumulative experience with intraoperative electrophysiological data and new mapping technologies should address these limitations.     

Multiple alignment of complete sequences (MACS) in the post-genomic era

Multiple alignment, since its introduction in the early seventies, has become a cornerstone of modern molecular biology. It has traditionally been used to deduce structure / function by homology, to detect conserved motifs and in phylogenetic studies. There has recently been some renewed interest in the development of multiple alignment techniques, with current opinion moving away from a single all-encompassing algorithm to iterative and / or co-operative strategies. The exploitation of multiple alignments in genome annotation projects represents a qualitative leap in the functional analysis process, opening the way to the study of the co-evolution of validated sets of proteins and to reliable phylogenomic analysis. However, the alignment of the highly complex proteins detected by today's advanced database search methods is a daunting task. In addition, with the explosion of the sequence databases and with the establishment of numerous specialized biological databases, multiple alignment programs must evolve if they are to successfully rise to the new challenges of the post-genomic era. The way forward is clearly an integrated system bringing together sequence data, knowledge-based systems and prediction methods with their inherent unreliability. The incorporation of such heterogeneous, often non-consistent, data will require major changes to the fundamental alignment algorithms used to date. Such an integrated multiple alignment system will provide an ideal workbench for the validation, propagation and presentation of this information in a format that is concise, clear and intuitive.     

An integrated analysis of the genome of the hyperthermophilic archaeon Pyrococcus abyssi

The hyperthermophilic euryarchaeon Pyrococcus abyssi and the related species Pyrococcus furiosus and Pyrococcus horikoshii, whose genomes have been completely sequenced, are presently used as model organisms in different laboratories to study archaeal DNA replication and gene expression and to develop genetic tools for hyperthermophiles. We have performed an extensive re-annotation of the genome of P. abyssi to obtain an integrated view of its phylogeny, molecular biology and physiology. Many new functions are predicted for both informational and operational proteins. Moreover, several candidate genes have been identified that might encode missing links in key metabolic pathways, some of which have unique biochemical features. The great majority of Pyrococcus proteins are typical archaeal proteins and their phylogenetic pattern agrees with its position near the root of the archaeal tree. However, proteins probably from bacterial origin, including some from mesophilic bacteria, are also present in the P. abyssi genome.     

Patterns of variability in the diameter of lateral roots in the banana root system

The relative importance of root system structure, plant carbon status and soil environment in the determination of lateral root diameter remains unclear, and was investigated in this study. Banana (Musa acuminata) plants were grown at various moderate levels of soil compaction in two distinct experiments, in a field experiment (FE) and in a glasshouse experiment (GE). Radiant flux density was 5 times lower in GE. The distribution of root diameter was measured for several root branching orders. Root diameters ranged between 0.09 and 0.52 mm for secondary roots and between 0.06 and 0.27 mm for tertiary roots. A relationship was found between the diameter of the parent bearing root and the median diameter of its laterals, which appears to be valid for a wide range of species. Mean lateral root diameter increased with distance to the base of the root and decreased with branching density [number of lateral roots per unit length of bearing root (cm(-1))]. Typical symptoms of low light availability were observed in GE. In this case, lateral root diameter variability was reduced. Although primary root growth was affected by soil compaction, no effects on lateral root diameter were observed.