Novel function of C5 protein as a metabolic stabilizer of M1 RNA

AbstractEscherichia coli RNase P is a ribonucleoprotein composed of a large RNA subunit (M1 RNA) and a small protein subunit (C5 protein). We examined if C5 protein plays a role in maintaining metabolic stability of M1 RNA. The sequestration of C5 protein available for M1 RNA binding reduced M1 RNA stability in vivo, and its reduced stability was recovered via overexpression of C5 protein. In addition, M1 RNA was rapidly degraded in a temperature-sensitive C5 protein mutant strain at non-permissive temperatures. Collectively, our results demonstrate that the C5 protein metabolically stabilizes M1 RNA in the cell

Direct observation of microscopic change induced by oxygen vacancy drift in amorphous TiO2 thin films

To clarify the resistive switching and failure mechanisms in Al/amorphous TiO2 /Al devices we investigate the microscopic change in amorphous titanium oxide films and interface layers after the set process according to film deposition temperatures. For low temperature (<150 ??C) samples, the thickness of top interface layer decreased after the set process due to the dissociation of a top interface layer by uniform migration of oxygen vacancies. Meanwhile, for high temperature samples, crystalline TiO phases emerged in the failed state, meaning the formation of conducting paths from the local clustering of oxygen vacancies in nonhomogeneous titanium oxide film.open221

A conserved circadian function for the Neurofibromatosis 1 gene

Summary: Loss of the Neurofibromatosis 1 (Nf1) protein, neurofibromin, in Drosophila disrupts circadian rhythms of locomotor activity without impairing central clock function, suggesting effects downstream of the clock. However, the relevant cellular mechanisms are not known. Leveraging the discovery of output circuits for locomotor rhythms, we dissected cellular actions of neurofibromin in recently identified substrates. Herein, we show that neurofibromin affects the levels and cycling of calcium in multiple circadian peptidergic neurons. A prominent site of action is the pars intercerebralis (PI), the fly equivalent of the hypothalamus, with cell-autonomous effects of Nf1 in PI cells that secrete DH44. Nf1 interacts genetically with peptide signaling to affect circadian behavior. We extended these studies to mammals to demonstrate that mouse astrocytes exhibit a 24-hr rhythm of calcium levels, which is also attenuated by lack of neurofibromin. These findings establish a conserved role for neurofibromin in intracellular signaling rhythms within the nervous system. : Bai et al. show that the gene mutated in the disease Neurofibromatosis 1 is required for maintaining levels or cycling of calcium in circadian neurons in Drosophila and in mammalian cells. These effects likely account for effects of Nf1 on circadian behavior in Drosophila and may be relevant in explaining sleep phenotypes in patients. Keywords: circadian rhythms, neurofibromatosis 1, Drosophila, peptide signaling, cycling of calcium, mouse astrocyte

Bezold-Jarisch Reflex Induced by Dopamine during Isoflurane Anesthesia in Small Dogs

Background: Unlike other major reflexes contributing to hemodynamic homeostasis, the Bezold-Jarisch reflex (BJR) paradoxically decreases heart rate (HR) and mean arterial pressure (MAP) despite hypotension. In the veterinary field, there are few reported cases of BJR induced by dopamine, which is often used to manage hypotension. Herein, 2 cases involving small dogs exhibiting BJR due to dopamine infusion during general anesthesia are described.Cases: Case 1: A 7-year-old, 7 kg, mongrel was referred for external skeletal fixator removal. The patient was premedicated with 0.3 mg/kg midazolam and 0.2 mg/kg butorphanol intravenously (IV). General anesthesia was induced with 6 mg/kg propofol and maintained with 1.6% isoflurane in oxygen. The patient was given 5 mL/kg/h of Hartmann’s solution IV. The respiratory rate (RR) was set to 9 breaths/min with a ventilator. The HR and MAP values were initially 120 bpm and 76 mmHg and gradually decreased to 70 bpm and 40 mmHg, respectively. The end-tidal CO2 partial pressure (ETCO2) was 39 mmHg, and the patient was administered 2.5 μg/kg glycopyrrolate IV. Then, 5 μg/kg/min dopamine was administered IV since the MAP did not improve. The HR, MAP, and ETCO2 increased to 113 bpm, 72 mmHg, and 47 mmHg, respectively. Subsequently, HR and MAP dramatically decreased to 50 bpm and 43 mmHg, respectively. A second-degree atrioventricular block was detected, prompting dopamine infusion discontinuation, and 2.5 μg/kg glycopyrrolate was again administered IV. Within 5 min, HR and MAP values normalized, and postoperative patient recovery was typical. Case 2: A 2-year-old, 8.6 kg, mongrel underwent surgery to correct a medial luxating patella of the right leg. The patient was premedicated with 0.3 mg/kg midazolam and 0.2 mg/kg butorphanol IV. Anesthesia was induced with 4 mg/kg propofol IV and maintained with 3% isoflurane in oxygen; 10 mL/kg/h of Hartmann’s solution was administered IV. Within 15 min, the patient’s HR and MAP values decreased from 120 to 107 bpm and 73 to 50 mmHg, respectively. The ETCO2remained approximately 39 mmHg, and RR decreased from 20 to 17 breaths/min. Dopamine was infused at a rate of 5 µg/kg/min. After 10 min, the MAP slightly increased from 50 to 57 mmHg, but the HR dramatically decreased from 107 to 62 bpm and the RR also dropped to 12 breaths/min. Further, a second-degree atrioventricular block was observed. Dopamine infusion was immediately discontinued, and 2.5 μg/kg glycopyrrolate was injected IV. As the HR returned to 94 bpm, the atrioventricular block disappeared, and the RR increased to 15 breaths/min. After general anesthesia was terminated, the patient recovered well.Discussion: Among drugs used for anesthesia, propofol and isoflurane may lower the MAP and HR. Therefore, HR or MAP decreases at the beginning of anesthesia are likely due to the drugs. Considering half-life, it is unlikely that propofol provoked sudden HR or MAP decreases at about 25 min post-induction. Isoflurane may also be ruled out since the hemodynamic disorder depended on dopamine injection. Sudden decreases in the HR, MAP, or RR after dopamine injection are not generally expected dopaminergic or adrenergic responses, which likely occur due to the vagal cardiopulmonary reflex suggesting the BJR resulting from activation of cardiac mechano- or chemoreceptors. To the best of our knowledge, there have been no reports of dopamine-mediated BJR in young or middle-aged, small dogs. The BJR has been observed in older, larger dogs and humans. In the patients described, body condition score may be considered when estimating the cause of the BJR. Since they scored 8/9, it is possible that obesity increased the risk of the BJR. This report described the clinical features and treatment outcomes in young or middle-aged, obese, small-sized dogs, whose hypotension or bradycardia was exacerbated by dopamine.Keywords: Bezold-Jarisch reflex, dopamine, hypotension, bradycardia, canine.

Phospholipase A2β mediates light-induced stomatal opening in Arabidopsis

Phospholipase A2 (PLA2) catalyses the hydrolysis of phospholipids into lysophospholipids and free fatty acids. Physiological studies have indicated that PLA2 is involved in stomatal movement. However, genetic evidence of a role of PLA2 in guard cell signalling has not yet been reported. To identify PLA2 gene(s) that is (are) involved in light-induced stomatal opening, stomatal movement was examined in Arabidopsis thaliana plants in which the expression of PLA2 isoforms was reduced or knocked-out. Light-induced stomatal opening in PLA2α knockout plants did not differ from wild-type plants. Plants in which PLA2β was silenced by RNA interference exhibited delayed light-induced stomatal opening, and this phenotype was reversed by exogenous lysophospholipids, which are products of PLA2. Stomatal opening in transgenic plants that over-expressed PLA2β was faster than wild-type plants. The expression of PLA2β was localized to the endoplasmic reticulum of guard cells, and increased in response to light in the mature leaf. Aristolochic acid, which inhibits light-induced stomatal opening, inhibited the activity of purified PLA2β. Collectively, these results provide evidence that PLA2β is involved in light-induced stomatal opening in Arabidopsis

Flexible room-temperature NO2 gas sensors based on carbon nanotubes/reduced graphene hybrid films

We present a flexible room temperature NO2 gas sensor consisting of vertical carbon nanotubes (CNTs)/reduced graphene hybrid film supported by a polyimide substrate. The reduced graphene film alone showed a negligible sensor response, exhibiting abnormal N-P transitions during the initial NO2 injection. A hybrid film, formed by the growth of a vertically aligned CNT array (with CNTs 20 ??m in length) on the reduced graphene film surface, exhibited remarkably enhanced sensitivities with weak N-P transitions. The increase in sensitivity was mainly attributed to the high sensitivity of the CNT arrays. The outstanding flexibility of the reduced graphene films ensured stable sensing performances in devices submitted to extreme bending stress.open786

Ecosystem model intercomparison of under-ice and total primary production in the Arctic Ocean

Previous observational studies have found increasing primary production (PP) in response to declining sea ice cover in the Arctic Ocean. In this study, under-ice PP was assessed based on three coupled ice-ocean-ecosystem models participating in the Forum for Arctic Modeling and Observational Synthesis (FAMOS) project. All models showed good agreement with under-ice measurements of surface chlorophyll-a concentration and vertically integrated PP rates during the main under-ice production period, from mid-May to September. Further, modeled 30-year (1980–2009) mean values and spatial patterns of sea ice concentration compared well with remote sensing data. Under-ice PP was higher in the Arctic shelf seas than in the Arctic Basin, but ratios of under-ice PP over total PP were spatially correlated with annual mean sea ice concentration, with higher ratios in higher ice concentration regions. Decreases in sea ice from 1980 to 2009 were correlated significantly with increases in total PP and decreases in the under-ice PP/total PP ratio for most of the Arctic, but nonsignificantly related to under-ice PP, especially in marginal ice zones. Total PP within the Arctic Circle increased at an annual rate of between 3.2 and 8.0 Tg C/yr from 1980 to 2009. This increase in total PP was due mainly to a PP increase in open water, including increases in both open water area and PP rate per unit area, and therefore much stronger than the changes in under-ice PP. All models suggested that, on a pan-Arctic scale, the fraction of under-ice PP declined with declining sea ice cover over the last three decades