The YlmG protein has a conserved function related to the distribution of nucleoids in chloroplasts and cyanobacteria

<p>Abstract</p> <p>Background</p> <p>Reminiscent of their free-living cyanobacterial ancestor, chloroplasts proliferate by division coupled with the partition of nucleoids (DNA-protein complexes). Division of the chloroplast envelope membrane is performed by constriction of the ring structures at the division site. During division, nucleoids also change their shape and are distributed essentially equally to the daughter chloroplasts. Although several components of the envelope division machinery have been identified and characterized, little is known about the molecular components/mechanisms underlying the change of the nucleoid structure.</p> <p>Results</p> <p>In order to identify new factors that are involved in the chloroplast division, we isolated <it>Arabidopsis thaliana </it>chloroplast division mutants from a pool of random cDNA-overexpressed lines. We found that the overexpression of a previously uncharacterized gene (<it>AtYLMG1-1</it>) of cyanobacterial origin results in the formation of an irregular network of chloroplast nucleoids, along with a defect in chloroplast division. In contrast, knockdown of <it>AtYLMG1-1 </it>resulted in a concentration of the nucleoids into a few large structures, but did not affect chloroplast division. Immunofluorescence microscopy showed that AtYLMG1-1 localizes in small puncta on thylakoid membranes, to which a subset of nucleoids colocalize. In addition, in the cyanobacterium <it>Synechococcus elongates</it>, overexpression and deletion of <it>ylmG </it>also displayed defects in nucleoid structure and cell division.</p> <p>Conclusions</p> <p>These results suggest that the proper distribution of nucleoids requires the YlmG protein, and the mechanism is conserved between cyanobacteria and chloroplasts. Given that <it>ylmG </it>exists in a cell division gene cluster downstream of <it>ftsZ </it>in gram-positive bacteria and that <it>ylmG </it>overexpression impaired the chloroplast division, the nucleoid partitioning by YlmG might be related to chloroplast and cyanobacterial division processes.</p

Development of temporal and spatial characteristics of anticipatory postural adjustments during gait initiation in children aged 3-10 years

This study aimed to analyze the development of direction specificities of temporal and spatial control and the coordination pattern of anticipatory postural adjustment (APA) along the anteroposterior (AP) and mediolateral (ML) directions during gait initiation (GI) in children aged 3-10 years. This study included 72 healthy children aged 3-10 years and 14 young adults. The child population was divided into four groups by age: 3-4, 5-6, 7-8, and 9-10 years. The GI task included GI using the dominant limb. The peak center of feet pressure (COP) shifts during APAs (APApeak), initiation time of COP shifts (APAonset), and the COP vectors in the horizontal plane were calculated to evaluate the direction specificity of spatial, temporal, and coordination control, respectively. A difference in direction specificity development was found for the APApeak. The APApeak in the mediolateral axis, but not in the anteroposterior axis, was significantly higher in the 7-8 years age group than in other groups. Although APAonset was not found for direction specificity, a significant difference between the adult and children groups (5-6 years, 7-8 years, and 9-10 years) was observed in the direction of the COP vector. In conclusion, the developmental process of the spatial, temporal, and coordination control of APAs during GI varied with age. Furthermore, the spatial control and coordination pattern of APAs was found to be direction specific. All components of APAs, namely temporal and spatial control, coordination pattern, and direction specificities, should be analyzed to capture the developmental process of anticipatory postural control

The effect of ezetimibe on lipid and glucose metabolism after a fat and glucose load

AbstractObjectivesThe clinical benefit of ezetimibe, an intestinal cholesterol transporter inhibitor, for treatment of postprandial hyperlipidemia was assessed in subjects who ingested a high-fat and high-glucose test meal to mimic westernized diet.MethodsWe enrolled 20 male volunteers who had at least one of the following: waist circumference ≥ 85cm, body mass index ≥ 25kg/m2, or triglycerides (TG) from 150 to 400mg/dL. After 4 weeks of treatment with ezetimibe (10mg/day), the subjects ingested a high-fat and high-glucose meal. Then changes in serum lipid and glucose levels were monitored after 0, 2, 4, and 6h, and the area under the curve (AUC) was calculated for the change in each parameter.Results and conclusionAt 4 and 6h postprandially, TG levels were decreased (p<0.01) after 4 weeks of ezetimibe treatment, and the AUC for TG was also decreased (p<0.01). Apolipoprotein B48 (apo-B48) levels at 4 and 6h postprandially were significantly decreased after ezetimibe treatment (p<0.01 and p<0.001, respectively), and the AUC for apo-B48 was also significantly decreased (p<0.01). Blood glucose and insulin levels at 2h postprandially were significantly decreased by ezetimibe (p<0.05). The AUCs for blood glucose and insulin were also significantly decreased (p<0.05 and p<0.01, respectively). Since ezetimibe improved postprandial lipid and glucose metabolism, this drug is likely to be beneficial for dyslipidemia in patients with postprandial metabolic abnormalities

Plastid chaperonin proteins Cpn60α and Cpn60β are required for plastid division in Arabidopsis thaliana

BACKGROUND: Plastids arose from a free-living cyanobacterial endosymbiont and multiply by binary division as do cyanobacteria. Plastid division involves nucleus-encoded homologs of cyanobacterial division proteins such as FtsZ, MinD, MinE, and ARC6. However, homologs of many other cyanobacterial division genes are missing in plant genomes and proteins of host eukaryotic origin, such as a dynamin-related protein, PDV1 and PDV2 are involved in the division process. Recent identification of plastid division proteins has started to elucidate the similarities and differences between plastid division and cyanobacterial cell division. To further identify new proteins that are required for plastid division, we characterized previously and newly isolated plastid division mutants of Arabidopsis thaliana. RESULTS: Leaf cells of two mutants, br04 and arc2, contain fewer, larger chloroplasts than those of wild type. We found that ARC2 and BR04 are identical to nuclear genes encoding the plastid chaperonin 60α (ptCpn60α) and chaperonin 60β (ptCpn60β) proteins, respectively. In both mutants, plastid division FtsZ ring formation was partially perturbed though the level of FtsZ2-1 protein in plastids of ptcpn60β mutants was similar to that in wild type. Phylogenetic analyses showed that both ptCpn60 proteins are derived from ancestral cyanobacterial proteins. The A. thaliana genome encodes two members of ptCpn60α family and four members of ptCpn60β family respectively. We found that a null mutation in ptCpn60α abolished greening of plastids and resulted in an albino phenotype while a weaker mutation impairs plastid division and reduced chlorophyll levels. The functions of at least two ptCpn60β proteins are redundant and the appearance of chloroplast division defects is dependent on the number of mutant alleles. CONCLUSION: Our results suggest that both ptCpn60α and ptCpn60β are required for the formation of a normal plastid division apparatus, as the prokaryotic counterparts are required for assembly of the cell division apparatus. Since moderate reduction of ptCpn60 levels impaired normal FtsZ ring formation but not import of FtsZ into plastids, it is suggested that the proper levels of ptCpn60 are required for folding of stromal plastid division proteins and/or regulation of FtsZ polymer dynamics

What Will Happen to Permanent Left Ventricular Assist Device Recipients? Clues from Long-Term Outcomes of Heterotopic Heart Transplants

Donor organ shortage and successful experience with left ventricular assist devices as a bridge to transplantation have prompted us to consider a permanent alternative to transplantation. However, we have little information on the long-term follow-up, because the left ventricular assist device has been used as a bridge to transplantation for a period of just over one year. In recipients of a left ventricular assist device, the potential heart-related complications expected include arrhythmia, thromboembolism, valvular heart disease, and progression of ischemic heart disease. Heterotopic heart transplantation (in which the native heart is retained) may be a good model to study long-term pathophysiological processes in the native heart. We analyzed the prevalence of native-heart-related complications in heterotopic heart transplantation to help in predicting the performance of the native heart in patients with a permanent left ventricular assist device. Between December 1984 and December 1994, 16 patients (13 men, 3 women, 37–60 years old) underwent heterotopic heart transplantation at the University of Pittsburgh. The indication for heterotopic heart transplantation in all recipients was pulmonary hypertension unresponsive to vasodilators. The one- and five-year survival rates after transplantation were 81% and 44%. Pulmonary hemodynamics improved significantly after the operation. The actuarial percentages of patients free of complications related to the native heart after one and four years were, respectively: ventricular arrhythmia: 85%, 75%; ischemic heart disease: 85%, 64%; and valvular heart disease: 100%, 88%. The actuarial freedom from all these complications was 70% after one year and 50% after four years. These results will give us an indication of the native heart performance to expect in the patient with a permanent left ventricular assist device

Open-label, randomized, comparative, phase III study on effects of reducing steroid use in combination with Palonosetron

The purpose of this study is to compare the efficacy of a single administration of dexamethasone (DEX) on day1 against DEX administration on days1-3 in combination with palonosetron (PALO), a second-generation 5-HT3 receptor antagonist, for chemotherapy-induced nausea and vomiting (CINV) in non-anthracycline and cyclophosphamide (AC) moderately-emetogenic chemotherapy (MEC). This phaseIII trial was conducted with a multi-center, randomized, open-label, non-inferiority design. Patients who received non-AC MEC as an initial chemotherapy were randomly assigned to either a group administered PALO (0.75mg, i.v.) and DEX (9.9mg, i.v.) prior to chemotherapy (study treatment group), or a group administered additional DEX (8mg, i.v. or p.o.) on days2-3 (control group). The primary endpoint was complete response (CR) rate. The CR rate difference was estimated by logistic regression with allocation factors as covariates. The non-inferiority margin was set at -15% (study treatment group - control group). From April 2011 to March 2013, 305patients who received non-AC MEC were randomly allocated to one of two study groups. Overall, the CR rate was 66.2% in the study treatment group (N=151) and 63.6% in the control group (N=154). PALO plus DEX day1 was non-inferior to PALO plus DEX days1-3 (difference, 2.5%; 95% confidence interval [CI]: -7.8%-12.8%; P-value for non-inferiority test=0.0004). There were no differences between the two groups in terms of complete control rate (64.9 vs 61.7%) and total control rate (49.7% vs 47.4%). Anti-emetic DEX administration on days2-3 may be eliminated when used in combination with PALO in patients receiving non-AC MEC