The role of subunit composition on prepulse facilitation of the cardiac L-type calcium channel

AbstractFacilitation of calcium current by depolarizing prepulses has been observed in many cells including cardiac muscle. The mechanism underlying prepulse facilitation is controversial with respect to the requirements of channel subunits and cAMP kinase. We found that coexpression of the cardiac α1C-a subunit with the cardiac β2a subunit significantly promotes the facilitation of IBa by strong depolarizing prepulses. The magnitude of IBa facilitation depended on the voltage potential of the prepulse and the interval duration between prepulse and test pulse. Prepulse facilitation was not affected by coexpression of AKAP79 and conditions favoring cAMP-dependent phosphorylation. Prepulse facilitation was also observed in cells expressing an α1C-a subunit which was truncated at residue 1733 removing the cAMP kinase site at Ser-1928. Facilitation was abolished by coexpression of the α2δ-1 or α2δ-3 subunit. We conclude that the expressed α1C-a β2a complex is sufficient to support prepulse facilitation. Facilitation is prevented by coexpression of the α2δ subunit

Macrophyte identity shapes water column and sediment bacterial community

By assembling mesocosms and utilizing high-throughput sequencing, we aim to characterize the shifts of the bacterial community in freshwaters driven by two contrasting submerged macrophyte species, Ceratophyllum demersum L. and Vallisneria spiralis L. Although the microbe in both the water column and sediment were largely modulated by the macrophyte, the effect varied considerably depending on bacterial locations and macrophyte species. Actinobacteria was the most abundant taxa in the water column of all the three treatments, but its abundances were significantly higher in the two planted treatments. Moreover, Alphaproteobacteria showed high abundance only in the unplanted control. For bacterial taxa in the sediment, C. demersum significantly increased the relative abundance of Anaerolineae but reduced the relative abundance of Betaproteobacteria and Gammaproteobacteria, while V. spiralis increased the relative abundance of Deltaproteobacteria and Gammaproteobacteria. Additionally, in the C. demersum treatment, the water column bacterial community increased more dramatically in richness, alpha diversity, and the relative abundance of the dominant taxa than those in the V. spiralis treatment. Taken together, the findings from this study reveal that the two species of submerged macrophyte modified the bacterial community in waters, despite the obvious interspecific performance differences

m-Azipropofol (AziPm) a Photoactive Analogue of the Intravenous General Anesthetic Propofol

Propofol is the most commonly used sedative-hypnotic drug for noxious procedures, yet the molecular targets underlying either its beneficial or toxic effects remain uncertain. In order to determine targets and thereby mechanisms of propofol, we have synthesized a photoactivateable analogue by substituting an alkyldiazirinyl moiety for one of the isopropyl arms but in the meta position. m-Azipropofol retains the physical, biochemical, GABAA receptor modulatory, and in vivo activity of propofol and photoadducts to amino acid residues in known propofol binding sites in natural proteins. Using either mass spectrometry or radiolabeling, this reagent may be used to reveal sites and targets that underlie the mechanism of both the desirable and undesirable actions of this important clinical compound

Chromosome-level genome and multi-omics analyses provide insights into the geo-herbalism properties of Alpinia oxyphylla

IntroductionAlpinia oxyphylla Miquel (A. oxyphylla), one of the “Four Famous South Medicines” in China, is an essential understory cash crop that is planted widely in the Hainan, Guangdong, Guangxi, and Fujian provinces. Particularly, A. oxyphylla from Hainan province is highly valued as the best national product for geo-herbalism and is an important indicator of traditional Chinese medicine efficacy. However, the molecular mechanism underlying the formation of its quality remains unspecified.MethodsTo this end, we employed a multi-omics approach to investigate the authentic quality formation of A. oxyphylla.ResultsIn this study, we present a high-quality chromosome-level genome assembly of A. oxyphylla, with contig N50 of 76.96 Mb and a size of approximately 2.08Gb. A total of 38,178 genes were annotated, and the long terminal repeats were found to have a high frequency of 61.70%. Phylogenetic analysis demonstrated a recent whole-genome duplication event (WGD), which occurred before A. oxyphylla’s divergence from W. villosa (~14 Mya) and is shared by other species from the Zingiberaceae family (Ks, ~0.3; 4DTv, ~0.125). Further, 17 regions from four provinces were comprehensively assessed for their metabolite content, and the quality of these four regions varied significantly. Finally, genomic, metabolic, and transcriptomic analyses undertaken on these regions revealed that the content of nootkatone in Hainan was significantly different from that in other provinces.DiscussionOverall, our findings provide novel insights into germplasm conservation, geo-herbalism evaluation, and functional genomic research for the medicinal plant A. oxyphylla

Competition between α-actinin and Ca2+-Calmodulin Controls Surface Retention of the L-type Ca2+ Channel CaV1.2

Regulation of neuronal excitability and cardiac excitation-contraction coupling requires proper localization of L-type Ca2+ channels. We show that the actin-binding protein α-actinin binds to the C-terminal surface targeting motif of α11.2, the central pore-forming CaV1.2 subunit, to foster its surface expression. Disruption of α-actinin function by dominant negative or shRNA constructs reduces CaV1.2 surface localization in HEK293 and neuronal cultures, and dendritic spine localization in neurons. We demonstrate that calmodulin displaces α-actinin from their shared binding site on α11.2 upon Ca2+ influx through L-type channels but not through NMDAR, thereby triggering loss of CaV1.2 from spines. Coexpression of a Ca2+-binding deficient calmodulin mutant does not affect basal CaV1.2 surface expression, but inhibits its internalization upon Ca2+ influx. We conclude that α-actinin stabilizes CaV1.2 at the plasma membrane, and that its displacement by Ca2+-calmodulin induces Ca2+-induced endocytosis of CaV1.2, thus providing an important negative feedback mechanism for Ca2+ influx

Baseline levels of serum high sensitivity C reactive protein and lipids in predicting the residual risk of cardiovascular events in Chinese population with stable coronary artery disease: a prospective cohort study

Abstract Background The contributions of inflammation, triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) to the residual risk of cardiovascular events have not been determined in a large cohort of Chinese population before. This study was aimed to investigate the association of serum levels of high sensitive C reactive protein (hs-CRP), TG and HDL-C with the residual risk of cardiovascular events in patients with stable coronary artery disease (CAD). Methods We enrolled 4090 patients with stable CAD from 13 hospitals in China. All participants received optimal medical treatment (OMT) for stable CAD suggested by guidelines and were followed. The endpoint measures were the first occurrence of a major adverse cardiovascular event (MACE), defined as cardiovascular death, non-fatal myocardial infarction, non-fatal stroke or unplanned coronary revascularization. Cox proportional regression analysis was conducted to identify independent predictors of MACE. Results We found that hs-CRP and HDL-C levels were associated with coronary lesion severity at baseline (both p < 0.001). After 3 months OMT, 91.2% (3730/4090) patients achieved the therapeutic goal for low density lipoprotein cholesterol (LDL-C) (< 1.8 mmoL/L). During a mean follow-up period of 39.5 months, 11.5% (471/4090) patients suffered MACE. In multivariate Cox proportional regression analysis, the hazard ratio for MACE was 1.17 (95% confidence interval: 1.07–1.28, p < 0.001) per standardized deviation in the log-transformed hs-CRP levels after adjustment for other traditional cardiovascular risk factors. However, baseline TG and HDL-C levels were not associated with MACE in this study. Conclusions Baseline hs-CRP level was an independent predictor of residual risk of cardiovascular events in Chinese population with stable CAD. However, TG and HDL-C levels were not associated with MACE

General trends in freshwater ecological restoration practice in China over the past two decades: the driving factors and the evaluation of restoration outcome

Background Although freshwater ecological restoration (FER) has undergone an immense development over the past two decades in China either in the number of projects or in the spatial scale of implementations, a dearth of clear and comprehensive trends in this field is still a particular concern. We conducted a literature survey through searching the database of Web of Science between 1997 and 2017 to investigate the driving force behind FER practice and to summarize the restoration outcomes. Results A total of 2047 publications were hit and 198 of them were finally retained after manual screening. The number of studies in this field has been steadily increasing in recent years and their provincial distribution is positively correlated with GDP growth and the investment to pollution control and environmental protection, suggesting that economic development is a key driving factor of FER practice. Among the remaining articles, nearly half (46.5%) focus on lake ecosystems, and 34.8% and 32.8% of the studies indicate that land reclamation and eutrophication are the predominant causes of freshwater ecosystem degradation. The overarching target of the restoration is biodiversity increase (31.4%), followed by water quality improvement (24.7%) and ecosystem services (23.9%). Revegetation is a dominant restoration approach (40.9%). Reference sites for assessment of restoration projects are normally control locations without intervention (60%), or the status of the targeted sites before the interventions. For the restoration outcome evaluation, 86% of the studies present positive outcomes in terms of water quality improvement, and 79% have improvement in biological features. The most frequently monitored organisms are macrophytes (31%), followed by benthos as indicators of ecological condition. Conclusions Economic growth, water pollution and investment into environmental protection are the main driving factors of FER practice in China. The effort of restoration and evaluation over the past two decades has not been limited to improving hydrological function and water quality, but also pay increasingly more attention to biological processes and ecological integrity, and further the ecosystem services in recent years. However, the lack of long-term monitoring and socioeconomic attributes considered in restoration success assessments are still particular issues that need to be addressed in the future FER researches and projects