PL-015 Aerobic exercise increases BKCa channel expression to enhance tracheal smooth muscle relaxation in a murine asthma model: There is no full paper associated with this abstract

Objective Increasing evidence has shown that moderate-intensity aerobic exercise training reduces airway hyperresponsiveness (AHR) in patients with asthma. However, the mechanisms underlying exercise-induced improvements in smooth muscle contractility have not been fully elucidated. Large-conductance Ca2+-activated K+ channels (BKCa) are expressed broadly on smooth muscle cells and play an important role in the regulation of smooth muscle contraction. We tested the hypothesis that exercise training increases the contribution of BKCa channel to tracheal smooth muscle relaxation in in ovalbumin (OVA)-challenged asthmatic rats. Methods Rats were sensitized/challenged with OVA or saline and exercised at a moderate intensity 5 times/week for 4 weeks. Tracheal smooth muscle contractility was tested. Membrane potential of primary cultured tracheal smooth muscle cells was measured. In addition, western immunoblotting was performed to study the expression levels of BKCa channel protein. Results The contraction of rat airway smooth muscle induced by carbachol was significantly increased with asthma and exercise training reversed this alteration. Application of BKCa channel agonist, NS1619, induced tracheal smooth muscle relaxation. NS1619-induced relaxation was decreased in asthmatic rats, however exercise training significantly increased NS1619-induced relaxation. In primary cultured smooth muscle cells, NS1619-induced membrane potential was reduced with asthma and this alteration was diminished after exercise training. Additionally, western blotting revealed that the protein expression of BKCa was reduced in asthmatic group and aerobic exercise significantly improved BKCa expression. Conclusions The present study reveals that aerobic exercise training increases BKCa expression on tracheal smooth muscle, which partly underlies the beneficial effect of exercise on improving airway smooth muscle relaxation in asthma

The Characteristics of Karst and Karst Water Hazards in Coal Mining Areas in North China

Abstract The characteristics of stratum distribution, karst evaluation and karst controlling factors in coal mining areas in North China were comprehensively studied and analyzed.The karst characteristics and the distribution of exposed karst ,shallow buried karst and deep buried karst were given. The relationship among geological structure controlling groundwater, groundwater circulation and the characteristics of Ordovician limestone karst was studied.The distribution characteristics of development types and water abundance of Ordovician limestone karst were obtained. The spatial relationship between major coal seams and Ordovician limestone karst aquifer, the main controlling factors of mine water hazards were studied. From the abundance water-charging sources, the capacity of water inrush-resisting of impermeable layers in seam floor, the geological formation of vertical karst and the development characteristics of water-conducting structures, evaluation of risk zonation of mine karst water hazards in coal mining areas in North China was put forward, providing important scientific basis for water hazard evaluation and control in mining deep coal resources in North China

Experimental study on the control effect of ground stress on the damage of coal seam mining floor

In order to study on mechanism of in-situ stress control on the coal floor damage during deep coal seam mining, the internal relationship among ground stress, mine pressure and floor water inrush was analyzed base on the increasing distribution rule of ground stress with the increasing depth of stratum. It is shown that the stress on the deep coal seam has obvious control effect on the depth of the floor damage and failure through the experimental study and the statistical analysis of the measured data of the mining damage depth of the coal seam floor. And the calculation formula for the depth of the floor failure in the deep seam mining was put forward

Experimental study on the control effect of ground stress on the damage of coal seam mining floor

In order to study on mechanism of in-situ stress control on the coal floor damage during deep coal seam mining, the internal relationship among ground stress, mine pressure and floor water inrush was analyzed base on the increasing distribution rule of ground stress with the increasing depth of stratum. It is shown that the stress on the deep coal seam has obvious control effect on the depth of the floor damage and failure through the experimental study and the statistical analysis of the measured data of the mining damage depth of the coal seam floor. And the calculation formula for the depth of the floor failure in the deep seam mining was put forward

Phylogenetic Analysis and Substitution Rate Estimation of Colonial Volvocine Algae Based on Mitochondrial Genomes

We sequenced the mitochondrial genome of six colonial volvocine algae, namely: Pandorina morum, Pandorina colemaniae, Volvulina compacta, Colemanosphaera angeleri, Colemanosphaera charkowiensi, and Yamagishiella unicocca. Previous studies have typically reconstructed the phylogenetic relationship between colonial volvocine algae based on chloroplast or nuclear genes. Here, we explore the validity of phylogenetic analysis based on mitochondrial protein-coding genes. We found phylogenetic incongruence of the genera Yamagishiella and Colemanosphaera. In Yamagishiella, the stochastic error and linkage group formed by the mitochondrial protein-coding genes prevent phylogenetic analyses from reflecting the true relationship. In Colemanosphaera, a different reconstruction approach revealed a different phylogenetic relationship. This incongruence may be because of the influence of biological factors, such as incomplete lineage sorting or horizontal gene transfer. We also analyzed the substitution rates in the mitochondrial and chloroplast genomes between colonial volvocine algae. Our results showed that all volvocine species showed significantly higher substitution rates for the mitochondrial genome compared with the chloroplast genome. The nonsynonymous substitution (dN)/synonymous substitution (dS) ratio is similar in the genomes of both organelles in most volvocine species, suggesting that the two counterparts are under a similar selection pressure. We also identified a few chloroplast protein-coding genes that showed high dN/dS ratios in some species, resulting in a significant dN/dS ratio difference between the mitochondrial and chloroplast genomes.</p

Comparison of colonial volvocine algae based on phylotranscriptomic analysis of gene family evolution and natural selection

This study is the first to determine the transcriptomes of eight colonial volvocine algae: Pandorina morum, P. colemaniae, Volvulina compacta, Eudorina elegans, E. cylindrica, Yamagishiella unicocca, Colemanosphaera charkowiensis and C. angeleri. By analysing these data together with the whole-genome data of Chlamydomonas reinhardtii and other colonial volvocine algae, we determined 26 979 gene families and 105 single-copy orthogroups. Using the single-copy orthogroups, we adopted a supermatrix and coalescent-based approach to perform phylotranscriptomic analysis of colonial volvocine algae. The phylogenetic relationships of most species were consistent with those of a previous study, and the results showed paraphyly of the genus Pandorina. Then, we analysed gene family expansion and contraction in colonial volvocine algae and found that they exhibited a large number of expanded and contracted gene families. In particular, the common ancestor of the Volvocaceae had the largest number of expanded gene families, which may be associated with the increased volume of extracellular matrix. Finally, using the ML method to analyse the substitution rates among colonial volvocine algae based on single-copy orthogroups, we showed a significantly higher non-synonymous substitution (dN) rate in Tetrabaena socialis. By analysing the differences in the dN/dS ratio, we found that more orthogroups exhibited a significantly higher dN/dS in T. socialis; we speculate that the higher dN/dS could indicate relaxed selection pressure and that this lower constraint allows the accumulation of more non-synonymous mutations in T. socialis.</p

Analysis of mitochondrial and chloroplast genomes in two volvocine algae: Eudorina elegans and Eudorina cylindrica (Volvocaceae, Chlorophyta)

The colonial volvocine algae span the full range of organizational complexity, from four-celled species to multicellular species, and this group of algae is often used for the study of evolution. In recent years, many organelle genomes have been sequenced using the application of next generation sequencing technology; however, only a few organelle genomes have been reported in colonial volvocine algae. In this study, we determined the organelle genomes of Eudorina elegans and Eudorina cylindrica and analysed the organelle genome size, structure and gene content between these volvocine species. This provided useful information to help us understand the composition of colonial volvocine organelle genomes. Based on the chloroplast genome protein-coding genes, we conducted a phylogenomics analysis of the volvocine algae. The result revealed an unexpected phylogenetic relationship, namely, E. elegans is more closely related to Pleodorina starrii than to E. cylindrica. The substitution rate of volvocine algae was then calculated based on organelle genome protein-coding genes; our analysis suggested the possibility that the two Eudorina species may be under similar evolutionary pressure. Lastly, the synteny analysis of the mitochondrial genome showed that gene arrangements and contents are highly conserved in the family Volvocaceae, and the synteny analysis of the chloroplast genome indicated that the genus Eudorina may have experienced genomic changes

Marker gene analysis reveals the spatial and seasonal variations in the eukaryotic phytoplankton community composition in the Yangtze River, Three Gorges Reservoir, China

The eukaryotic phytoplankton community in the Three Gorges Reservoir (TGR) of the Yangtze River in China was investigated, based on marker gene analysis of the 18S rRNA V4 region. Community composition was investigated in four seasons (to assess seasonal variation) and in the mainstream and tributary of the river (to assess spatial variation). Chlorophyll a concentration was used to estimate eukaryotic phytoplankton biomass. A significant negative correlation of biomass and evenness was found in the TGR; this relationship may be due to a few highly competitive species dominating the eukaryotic phytoplankton community, suggesting that eukaryotic phytoplankton bloom events tend to occur in such communities. Our results showed that eukaryotic phytoplankton is more likely to bloom in the tributary when compared with mainstream, and we identified two unreported algal blooms, Tetraselmis and Mychonastes. Phylogenetic analysis revealed a novel lineage in Cryptophyta and substantially more diverse species in Bacillariophyta, two high relative abundance operational taxonomic units in Bacillariophyta classified to Peridiniopsis diatom endosymbionts; their high relative abundance may result from a high relative abundance of the genus Peridiniopsis. We found that Cryptomonas was the most widely distributed genus and had the highest relative abundance, and species in TGR that have higher relative abundance tend to be distributed more widely

Evolutionary Analysis of Unicellular Species in Chlamydomonadales Through Chloroplast Genome Comparison With the Colonial Volvocine Algae

This study is the first determination of six chloroplast genomes of colonial volvocine algae, Colemanosphaera charkowiensis, Volvulina compacta, Pandorina colemaniae, Pandorina morum, Colemanosphaera angeleri, and Yamagishiella unicocca. Based on 55 chloroplast protein-coding genes, we compared the nonsynonymous (dN) and synonymous (dS) substitution rates between colonial volvocine algae and the other unicellular Chlamydomonadales species. When refer to the dN, we found 27 genes were significantly different, among them, 19 genes were significant higher in unicellular species (FDR-adjusted P < 0.05). When refer to the dS, we found 10 genes were significantly different, among them, 6 genes were significant higher in unicellular species (FDR-adjusted P < 0.05). Then we identified 14 putative fast-evolving genes and 11 putative positively selected genes of unicellular species, we analyzed the function of positively selected sites of the overlap genes of putative fast-evolving and positively selected genes, and found some sites were close to the important functional region of the proteins. Photosynthesis is the process to transform and store solar energy by chloroplast, it plays a vital role in the survival of algae, this study is the first to use the chloroplast genomes to analysis the evolutionary relationship between colonial and unicellular species in Chlamydomonadales. We found more genes have higher substitution rates in unicellular species and proposed that the fast-evolving and positively selected two genes, psbA and psbC, may help to improve the photosynthetic efficiency of unicellular species in Chlamydomonadales