Deterministic assembly of grassland soil microbial communities driven by climate warming amplifies soil carbon loss

Perturbations in soil microbial communities caused by climate warming are expected to have a strong impact on biodiversity and future climate-carbon (C) feedback, especially in vulnerable habitats that are highly sensitive to environmental change. Here, we investigate the impact of four-year experimental warming on soil microbes and C cycling in the Loess Hilly Region of China. The results showed that warming led to soil C loss, mainly from labile C, and this C loss is associated with microbial response. Warming significantly decreased soil bacterial diversity and altered its community structure, especially increasing the abundance of heat-tolerant microorganisms, but had no effect on fungi. Warming also significantly increased the relative importance of homogeneous selection and decreased "drift" of bacterial and fungal communities. Moreover, warming decreased bacterial network stability but increased fungal network stability. Notably, the magnitude of soil C loss was significantly and positively correlated with differences in bacterial community characteristics under ambient and warming conditions, including diversity, composition, network stability, and community assembly. This result suggests that microbial responses to warming may amplify soil C loss. Combined, these results provide insights into soil microbial responses and C feedback in vulnerable ecosystems under climate warming scenarios.

Acid rain reduced soil carbon emissions and increased the temperature sensitivity of soil respiration: A comprehensive meta-analysis

Soil respiration the second-largest carbon flux in terrestrial ecosystems, has been extensively studied across a wide range of biomes. Surprisingly, no consensus exist on how acid rain (AR) impacts the spatiotemporal pattern of soil respiration. Therefore, we conducted a meta-analysis using 318 soil respiration and 263 soil respiration temperature sensitivity (Q10) data points obtained from 48 studies to assess the impact of AR on soil respiration components and their Q10. The results showed that AR reduced soil total respiration (Rt) and soil autotrophic respiration (Ra) by 7.41 % and 20.75 %, respectively. As the H+ input increased, the response rates of Ra to AR (RR-Ra) and soil heterotrophic respiration (Rh) to AR (RR-Rh) decreased and increased, respectively. With increased AR duration, the RR-Ra increased, whereas the RR-Rh did not change. AR increased the Q10 of Rt (Rt-Q10) and Rh (Rh-Q10) by 1.92 % and 9.47 %, respectively, and decreased the Q10 of Ra (Ra-Q10) by 2.77 %. Increased mean annual temperature, mean annual precipitation, and initial soil organic carbon increased the response rate of Ra-Q10 to AR (RR-Ra-Q10) and decreased the response rate of Rh-Q10 to AR (RR-Rh-Q10). However, as the AR frequency and initial soil pH increased, both RR-Ra-Q10 and RR-Rh-Q10 also increased. In summary, AR decreased Rt but increased Q10, likely due to soil acidification (soil pH decreased by 7.84 %), reducing plant root biomass (decreased by 5.67 %) and soil microbial biomass (decreased by 5.67 %), changing microbial communities (increased fungi to bacteria ratio of 15.91 %), and regulated by climate, vegetation, soil and AR regimes. To the best of our knowledge, this is the first study to reveal the large-scale, varied response patterns of soil respiration components and their Q10 to AR. It highlights the importance of applying the reductionism theory in soil respiration research to enhance our understanding of soil carbon cycling processes with in the context of global climate change.

P-limitation regulates the accumulation of soil aggregates organic carbon during the restoration of Pinus tabuliformis forest

Artificial forest restoration is widely recognized as a crucial approach to enhance the potential of soil carbon sequestration. Nevertheless, there is still limited understanding regarding the dynamics of aggregate organic carbon (OC) and the underlying mechanisms driving these dynamics after artificial forest restoration. To address this gap, we studied Pinus tabuliformis forests and adjacent farmland in three recovery periods (13, 24 and 33 years) in the Loess Plateau region. Samples of undisturbed soil from the surface layer were collected and divided into three aggregate sizes: >2 mm (large aggregate), 0.25-2 mm (medium aggregate), and <0.25 mm (small aggregate). The aim was to examine the distribution of OC and changes in enzyme activity within each aggregate size. The findings revealed a significant increase in OC content for all aggregate sizes following the restoration of Pinus tabuliformis forests. After 33 years of recovery, the OC of large aggregates, medium aggregates and micro-aggregates increased by (30.23 ± 9.85)%, (36.71 ± 21.60)% and (37.88 ± 16.07)% respectively compared with that of farmland. Moreover, the restoration of Pinus tabuliformis forests lead to increased activity of hydrolytic enzymes and decreased activity of oxidative enzymes. It is noteworthy that the regulation of carbon in all aggregates is influenced by soil P-limitation. In large aggregates, P-limitation promotes the enhancement of hydrolytic enzyme activity, thereby facilitate OC accumulation. Conversely, in medium and small aggregates, P-limitation inhibits the increase in oxidative enzyme activity, resulting in OC accumulation. The results emphasize the importance of P-limitation in regulating OC accumulation during the restoration of Pinus tabulaeformis forest, in which large aggregates play a leading role.

Unknown bacterial species lead to soil CO2 emission reduction by promoting lactic fermentation in alpine meadow on the Qinghai-Tibetan Plateau

Highly variable soil microbial respiration among grasslands has been identified as a major cause of uncertainty in regional carbon (C) budget estimation in the Qinghai-Tibetan Plateau; microbial metabolism mechanisms might explain this variation, but remain elusive. Therefore, we investigated soil CO2 production in incubated soils and detected the associated functional genes at four sampling sites from two major alpine grasslands on the Qinghai-Tibetan Plateau. The results showed that the cumulative CO2 emissions from alpine meadow soils were 71 %-83 % lower than those from alpine steppe soils. Both the enriched genes abundance encoding fermentation and glycolysis (Embden-Meyerhof pathway (EMP)) and the diminished genes encoding tricarboxylic acid cycle (TCA) and phosphate pentose pathway (PPP) explained the CO2 emission reduction in the alpine meadow soils. The EMP: PPP and fermentation: TCA cycle ratios in alpine meadow soils were 1.45- and 1.50-fold higher than those in alpine steppe soils, respectively. Such shifts in metabolic pathways were primarily caused by the increasing dominance of an unknown species of Desulfobacteraceae with high glycolytic potential, carrying a higher abundance of ldh genes during fermentation. These unknown species were promoted by warmer temperatures and higher precipitation in the alpine meadows. Further studies on the unknown species would enhance our understanding and predictability of C cycling in alpine grasslands.

Cross-linked modifications of starches from colored highland barley and their characterizations, digestibility, and lipolysis inhibitory abilities in vitro

To promote the stability and functionality of native starch from colored highland barley (CHBS), the cross-linked modifications with sodium trimetaphosphate (STMP)/sodium tripolyphosphate (STPP) and citric acid were conducted to prepare CHB resistant starches (CHRSs), whose physicochemical characteristics, digestibility, and lipolysis inhibitory potential were also assessed. Results showed that the resistant starch amounts in CHBS were significantly increased after cross-linking and differed slightly among CHRSs. Citric acid modification of CHBS resulted in significantly higher amylose amounts, solubilities, swelling powers, and water-binding capacities than those under STMP/STPP modification within the cultivars (p < 0.05), with their crystalline patterns of A-type (white and blue) and CB-type (black). STMP/STPP modified CHBS exhibited higher degrees of crystalline regions with B-type crystalline patterns. Due to the differences in structural properties and structure-based morphology, STMP/STPP cross-linked CHBS showed lower digestibility and citric acid cross-linked CHBS exhibited higher lipolysis inhibitory activities. Besides, the cross-linked modifications demonstrated more enhancements in functionalities of starches from white and blue cultivars than black cultivar.

Natural restoration exhibits better soil bacterial network complexity and stability than artificial restoration on the Loess Plateau, China

Natural restoration (NR, e.g., secondary succession) and artificial restoration (AR, e.g., afforestation) are key approaches for rehabilitating degraded land; however, a comparative assessment of microbial network between these approaches is lacking. We compared bacterial networks under NR and AR in two different watersheds on the Loess Plateau. Our findings revealed significantly heightened network complexity under NR compared to AR, including metrics such as node, edge, modularity, degree, centrality, and keystone nodes. NR's network robustness exceeded AR by 19.45-35.9% and 7.79-17.74% in the two watersheds, aligning with the ecological principle that complexity begets stability. The significantly higher negative/positive cohesion and natural connectivity under NR also support its better network stability than AR. Integrated analysis of paired sequencing data from five Loess Plateau studies conducted on the Loess Plateau further confirmed the higher complexity and stability of bacterial networks under NR. Further analysis unveiled "biological interactions" as primary drivers of bacterial co-occurrence (on average 84.21% of links), surpassing the influence of environmental filtering (5.17%) or dispersal limitation (4.2%). Importantly, networked communities under NR exhibited generally stronger linkages with various ecosystem function than AR. Overall, our study provides insights into vegetation restoration strategies from the perspective of microbial network, underscoring natural regeneration's potential as a superior remedy for degraded-land restoration.

Effects of straw and plastic film mulching on microbial functional genes involved in soil nitrogen cycling

Introduction

Microorganisms regulate soil nitrogen (N) cycling in cropping systems. However, how soil microbial functional genes involved in soil N cycling respond to mulching practices is not well known.

Methods

We collected soil samples from a spring maize field mulched with crop straw (SM) and plastic film (FM) for 10-year and with no mulching (CK) in the Loess Plateau. Microbial functional genes involved in soil N cycling were quantified using metagenomic sequencing. We collected soil samples from a spring maize field mulched with crop straw (SM) and plastic film (FM) for 10-year and with no mulching (CK) in the Loess Plateau. Microbial functional genes involved in soil N cycling were quantified using metagenomic sequencing.

Results

Compared to that in CK, the total abundance of genes involved in soil N cycling increased in SM but had no significant changes in FM. Specifically, SM increased the abundances of functional genes that involved in dissimilatory nitrate reduction to ammonium (nirB, napA, and nrfA), while FM decreased the abundances of functional genes that involved in ammonification (ureC and ureA) in comparison with CK. Other genes involved in assimilatory nitrate reduction, denitrification, and ammonia assimilation, however, were not significantly changed with mulching practices. The nirB and napA were derived from Proteobacteria (mainly Sorangium), and the ureC was derived from Actinobacteria (mainly Streptomyces). Mental test showed that the abundance of functional genes that involved in dissimilatory nitrate reduction was positively correlated with the contents of soil microbial biomass N, potential N mineralization, particulate organic N, and C fractions, while ammonification related gene abundance was positively correlated with soil pH, microbial biomass C and N, and mineral N contents.

Discussion

Overall, this study showed that SM could improve soil N availability and promote the soil N cycling by increasing the abundance of functional genes that involved in DNRA, while FM reduced the abundance of functional genes that involved in ammonification and inhibited soil N cycling.

First Report of Tomato mottle mosaic virus infecting Chinese snake gourd (Trichosanthes kirilowii) in China

Tomato mottled mosaic virus (ToMMV) was first identified in tomato in Mexico (Li et al. 2013). It belongs to the genus Tobamovirus and family Virgaviridae, and is a positive-sense single-stranded RNA virus. The viral genome contains about 6400 nucleotides, encoding four proteins, including the 126 K protein, 183 K protein, movement protein (MP) and coat protein (CP) (Tu et al. 2021). ToMMV mainly poses a serious risk to solanaceous crops. The virus-infected plants appear stunted growth and top necrosis, and the disease leaves show mottled, shrinkage and necrosis symptoms, resulting in a significant decline in tomato fruit yield and quality (Li et al. 2017; Tu et al. 2021). Chinese snake gourd (Trichosanthes kirilowii Maxim) is a perennial climbing herb in the family Cucurbitaceae, and the fruit, seed, peel and root can all be used as traditional Chinese medicine. In May of 2021, twenty-seven symptomless seedlings (developed from tissue culture plantlets) were randomly collected from nursery in Fengyang, Anhui Province. Total RNA of each sample was extracted, and RT-PCR was performed using degenerate tobamovirus primers Tob-Uni1 (5'-ATTTAAGTGGASGGAAAAVCACT-3') and Tob-Uni2 (5'-GTYGTT GATGAGTTCRTGGA-3') (Letschert et al. 2002). Amplicons with expected size were obtained from 6 of 27 samples and sequenced. Alignment results showed that the nucleotide sequence identities ranged from 98.7 to 100% with all ToMMV isolates deposited in NCBI GenBank. Then, ToMMV coat protein (CP) gene was amplified using specific primers CP-F (5'-ATGTCTTACGCTATTACTT CTCCG-3') and CP-R (5'-TTAGGACGCTGGCGCAGAAG-3'). The CP fragment was obtained and sequenced. Sequence alignment indicated that CP sequence of isolate FY (GenBank accession no. ON924176) exhibited a 100% identity with ToMMV isolate LN (MN853592.1). The anti-ToMMV polyclonal antibody (PAb) was prepared by the author (S.L.) by immunizing rabbit with purified virus from Nicotiana benthamiana, and serological tests (dot-enzyme linked immunosorbent assay, Dot-ELISA) of RNA-positive T. kirilowii leaf samples using anti-ToMMV PAb were also positive. To fulfill a Koch's postulate, a pure culture of ToMMV was obtained from N. benthamiana using infectious cDNA clone of ToMMV (Tu et al. 2021), and then healthy T. kirilowii plants were mechanically inoculated with a prepared inoculum from ToMMV-infected N. benthamiana, as described previously (Sui et al. 2017). T. kirilowii seedlings showed chlorosis and leaf tip necrosis symptoms at 10 and 20 day post-inoculation respectively, and ToMMV infection on symptomatic plants was also verified by RT-PCR detection using primers CP-F and CP-R. These results demonstrated that T. kirilowii is a host of ToMMV under natural conditions, which might threaten the production of this medicinal plant. The seedlings from nursery appeared to be asymptomatic, but the plants showed chlorosis and necrosis symptoms after indoor inoculation. In qRT-PCR analysis, viral accumulation level in greenhouse-inoculated plants was a 25.6-fold of that in field-collected samples, which may be the reason of different symptom expression between field samples and inoculated samples. ToMMV has now been detected from the solanaceous (tomato, pepper and eggplant) and leguminous (pea) crops in the field (Li et al. 2014; Ambrós et al. 2017; Zhang et al. 2022). To our knowledge, this is the first report of natural infection of ToMMV in T. kirilowii as well as its natural infection on Cucurbitaceae plants.

Genome-wide identification and expression analysis of SlRR genes in response to abiotic stress in tomato

The cytokinin two-component signal transduction system (TCS) is involved in many biological processes, including hormone signal transduction and plant growth regulation. Although cytokinin TCS has been well characterized in Arabidopsis thaliana, its role in tomato remains elusive. In this study, we characterized the diversity and function of response regulator (RR) genes, a critical component of TCS, in tomato. In total, we identified 31 RR genes in the tomato genome. These SlRR genes were classified into three subgroups (type-A, type-B and type-C). Various stress-responsive cis-elements were present in the tomato RR gene promoters. Their expression responses under pesticide treatment were evaluated by transcriptome analysis. Their expression under heat, cold, ABA, salinity and NaHCO₃ treatments was further investigated by qRT-PCR and complemented with the available transcription data under these treatments. Specifically, SlRR13 expression was significantly upregulated under salinity, drought, cold and pesticide stress and was downregulated under ABA treatment. SlRR23 expression was induced under salt treatment, while the transcription level of SlRR1 was increased under cold and decreased under salt stress. We also found that GATA transcription factors played a significant role in the regulation of SlRR genes. Based on our results, tomato SlRR genes are involved in responses to abiotic stress in tomato and could be implemented in molecular breeding approaches to increase resistance of tomato to environmental stresses.

Altered microbial P cycling genes drive P availability in soil after afforestation

Soil Phosphorous (P) availability is a limiting factor for plant growth and regulates biological metabolism in plantation ecosystems. The effect of variations in soil microbial P cycling potential on the availability of soil P during succession in plantation ecosystems is unclear. In this study, a metagenomics approach was used to explore variations in the composition and diversity of microbial P genes along a 45-year recovery sequence of Robinia pseudoacacia on the Loess Plateau, as well soil properties were measured. Our results showed that the diversity of P cycling genes (inorganic P solubilization and organic P mineralization genes) increased significantly after afforestation, and the community composition showed clear differences. The gcd and ppx genes were dominant in inorganic P transformation, whereas phnM gene dominated the transformation of organic P. The abundance of genes involved in inorganic P solubilization and organic P mineralization was significantly positively correlated with P availability, particularly for phnM, gcd, ppx, and phnI genes, corresponding to the phyla Gemmatimonadetes, Acidobacteria, Bacteroidetes, and Planctomycetes. The critical drivers of the microbial main genes of soil P cycling were available P (AP) and total N (TN) in soil. Overall, these findings highlight afforestation-induced increases in microbial P cycling genes enhanced soil P availability. and help to better understand how microbial growth metabolism caused by vegetation restoration in ecologically fragile areas affects the soil P cycling.

Predicting hot electron generation in inertial confinement fusion with particle-in-cell simulations

A series of two-dimensional particle-in-cell simulations with speckled laser drivers was carried out to study hot electron generation in direct-drive inertial confinement fusion on OMEGA. Scaling laws were obtained for hot electron fraction and temperature as functions of laser/plasma conditions in the quarter-critical region. Using these scalings and conditions from hydro simulations, the temporal history of hot electron generation can be predicted. The scalings can be further improved to predict hard x-rays for a collection of OMEGA warm target implosions within experimental error bars. These scalings can be readily implemented into inertial confinement fusion design codes.

Different mechanisms driving increasing abundance of microbial phosphorus cycling gene groups along an elevational gradient

Microbes play an integral role in forest soil phosphorus (P) cycling. However, the variation of microbial P-cycling functional genes and their controlling factors in forest soils is unclearly. We used metagenomics to investigate changes in the abundance of genes involved in P-starvation response regulation, P-uptake and transport, and P-solubilization and mineralization along the five elevational gradients. Our results showed the abundance of three P cycling gene groups increasing along the elevational gradient. Acidobacteria and Proteobacteria were the dominant microbial phyla determining the turnover of soil P-solubilization and immobilization. Along the elevational gradient, soil substrates are the major factor explaining variation in P-starvation response regulation genes. Soil environment is the main driver of P-uptake and transport and P-solubilization and mineralization genes. This study provided insights into the regulation of P-cycling from a microbial functional profile perspective, highlighting the importance of substrate and environmental factors for P-cycling genes in forest soils.

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P-cycling functional genes increased along the elevational gradient

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Acidobacteria and Proteobacteria are the key phyla for P cycle in forest soils

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Microbial functional gene groups for P-cycling were driven by different factors

Soil microbial nitrogen-cycling gene abundances in response to crop diversification: A meta-analysis

Single planting structure has a significant impact on the maintenance of nitrogen in managed ecosystems. Although the effect of crop diversity on soil nitrogen-cycling microbes is mainly related to the influence of environmental factors, there is a lack of quantitative research. This study aims to determine the effect of diversified cropping mode on the abundance of functional genes in the soil nitrogen cycle based on the quantitative integration of a meta-analysis database containing 189 observation data pairs. The results show that the soil nifH (nitrogenase coding gene), nirS and nirK (nitrite reductase coding gene), and narG (nitrate reductase coding gene) abundances are positively affected by the diversity of plant species, whereas the amoA (ammonia monooxygenase coding gene) and nosZ (nitrous oxide reductase coding gene) show no response. Diversification duration and ecosystem type are important factors that regulate soil nitrogen fixation and nitrification gene abundances. Denitrification genes are mainly affected by categorical variables such as the planting pattern, soil layer, application species, duration, and soil texture. Among them, the long-term continuous diversification is mainly manifested in the reduction of soil nifH and increase of nirK abundances. Soil organic carbon and nitrogen linearly affect the responses of nifH, amoA, nirS, and nirK. Therefore, to maintain the soil ecological function, diversity of planting patterns needs to be applied flexibly by regulating the abundance of nitrogen-cycling genes. Our study draws conclusions in order to provide theoretical references for the sustainability of nitrogen and improvement of management measures in the process of terrestrial managed ecosystem diversification.

[Correlation analysis of clock genes and MEN2 medullary thyroid carcinoma]

Objective: To investigate the correlation between CLOCK and BMAL1 genes and MEN2 medullary thyroid carcinoma (MTC). Methods: Thirteen cases with MEN2 MTC and thirteen cases with non-MEN2 MTC were selected who were treated in the Yantai Yuhuangding Hospital between January 2013 and September 2021. Clinical indicators such as blood calcitonin level, tumor diameter and metastatic lymph node of patients were collected. The expression differences of CLOCK and BMAL1 between MEN2 MTC and para-carcinoma tissue as well as between MEN2 MTC and non-MEN2 MTC were detected by immunohistochemistry and qPCR. The correlation between lymph node metastasis and CLOCK or BMAL1 expression was analyzed. Protein-protein interaction (PPI) network analysis combined with qPCR and correlation analysis was used to explore the expression regulation relationship between RET and circadian clock genes. The rhythm disorder of MEN2 cells was verified by lipopolysaccharide cell stimulation experiment after dexamethasone rhythm synchronization. Results: MEN2 MTC exhibited typical RET gene mutation. The mean blood calcitonin level, the tumor diameter and the number of metastatic lymph nodes of patients with MEN2 MTC were higher than those of patients with non-MEN2 MTC (t value was 2.76, 2.53, 2.26, all P<0.05). Immunohistochemical results showed that the expression levels of CLOCK and BMAL1 in MEN2 MTC were higher than those in non-MEN2 MTC, while negatively expressed in para-cancerous thyroid follicle. qPCR displayed that the expression of CLOCK gene in cancer tissues was higher than that in non-MEN2 MTC and para-cancerous tissues (t value was 2.68 and 2.86, all P<0.05); the expression of BMAL1 gene in MEN2 MTC was higher than that in non-MEN2 MTC and para-cancerous tissues (t value was 2.21 and 2.35, all P<0.05). Correlation analysis showed that the expression levels of CLOCK and BMAL1 genes were positively correlated with the number of lymph node metastases in patients with MEN2 MTC (r=0.65, P<0.001; r=0.52, P=0.005). PPI network analysis indicated that the expression of CLOCK gene was positively correlated with the abnormal expression of RET gene (r=0.96, P<0.001). With lipopolysaccharide to stimulate cultured cells in vitro after dexamethasone rhythm synchronization, the expressions of CLOCK and BMAL1 in MEN2 MTC cells (0.47±0.22 and 2.60±1.48) at 12 hours of synchronization were significantly lower than those in para-cancerous tissues (1.70±1.62 and 8.23±2.52), the difference was statistically significant(t=5.04, P=0.007; t=3.34, P=0.029). Conclusion: CLOCK and BMAL1 are correlated with the occurrence and development of MEN2 MTC, and may be potential targets for the development of new therapeutic strategies for MEN2 MTC.

Global pattern of soil priming effect intensity and its environmental drivers

The microbial priming effect - the decomposition of soil organic carbon (SOC) induced by plant inputs - has long been considered an important driver of SOC dynamics, yet we have limited understanding about the direction, intensitiy, and drivers of priming across ecosystem types and biomes. This gap hinders our ability to predict how shifts in litter inputs under global change can affect climate feedbacks. Here, we synthesized 18,919 observations of CO₂ effluxes in 802 soils across the globe to test the relative effects (i.e., log response ratio; RR) of litter additions on native SOC decomposition, and identified the dominant environmental drivers in natural ecosystems and agricultural lands. Globally, litter additions enhanced native SOC decomposition (RR = 0.35, 95% CI: 0.32 ~ 0.38), with greater priming effects occurring with decreasing latitude, and more in agricultural soils (RR = 0.43) than in uncultivated soils (RR = 0.28). In natural ecosystems, soil pH and microbial community composition (e.g., bacteria:fungi ratio) were the best predictors of priming, with greater effects occurring in acidic, bacterial-dominated, sandy soils. In contrast, substrate properties of plant litter and soils were the most important drivers of priming in agricultural systems, as soils with high C:N ratio and those receiving large inputs of low quality litter had the highest priming effects. Collectively, our results suggest that while different factors may control priming effects, the ubquitious nature of priming means that alterations of litter quality and quantity owing to global changes will likely have consequences for global C cycling and climate forcing.

Variability of right ventricular linear measurements of size and function using a standardized echocardiographic protocol

Funding Acknowledgements

Type of funding sources: None.

Background

Right ventricular size and function have a prognostic value not only in right heart conditions (pulmonary hypertension, congenital heart disease), but also in left ventricular (LV) disease states. The right ventricle (RV) has a unique shape, for which a simple geometrical model is not achievable as is the case for the LV. In clinical practice simple measurements are used for the RV, since these are considered to be most reliable  and reproducible: linear cavity dimensions, tricuspid annular plane systolic excursion (TAPSE) and tissue Doppler systolic velocity s’ at the tricuspid annulus. The latest RV quantitation guidelines made important modifications to RV measurements, in particular, by shifting from the apical 4-chamber view to the RV focused apical view. Very scarce data exist on the variability of these measurements.

Purpose

In this study we aim to analyze the intra and inter-observer variability of the linear measurements of RV size and function using a standardized methodology.

Methods

A mixed cohort, randomly selected from the echocardiographic database, comprising 50 patients, was retrospectively analyzed. We measured linear diameters (basal = 1, longitudinal = 2, mid = 3) in apical RV-focused view, TAPSE and s’. Based on computer simulations, we propose a step-by-step approach: tracing the longitudinal diameter as perpendicular to the mid of the basal and generally parallel with the interventricular septum, and the mid as perpendicular to the middle of the longitudinal (Figure). Two observers measured independently the same images at baseline, three (inter-observer) and six months (intra-observer).

Results

The longitudinal diameter had the lowest relative bias (3% inter and 4% intra-observer), followed by the basal (7% and 2%), and mid (6% and 6%). The limits of agreement (LOA) were small for s’ (-3 to 1 intra and -1 to 1mm inter-observer), TAPSE (-6 to 5 and -3 to 3mm), and larger for diameters (1=-5 to 10 and -8 to 6; 2=-13 to 17 and -11 to 6; 3=-11 to 7 and -9 to 4mm). ICCs for individual measurements were very good (1= 0.94 intra and 0.94 inter; 2 = 0.78 and 0.94; 3: 0.72 and 0.56; TAPSE: 0.86 and 0.94; s’=0.94 and 0.98), p &lt; 0.001 for all (Table).

Conclusion

A systematic approach to linear RV-focused apical view measurements may lead to reproducible results. It is essential that size measurements be performed in the RV focused view. Our study shows best consistency and reproducibility for the basal diameter and the linear functional parameters.  Echocardiographic laboratories may benefit from implementing a consistent analysis protocol and assessing its reproducibility. Abstract Figure: linear RV measurements  Abstract Table: variability results

Microbial traits determine soil C emission in response to fresh carbon inputs in forests across biomes

Soil priming is a microbial-driven process, which determines key soil-climate feedbacks in response to fresh carbon inputs. Despite its importance, the microbial traits behind this process are largely undetermined. Knowledge of the role of these traits is integral to advance our understanding of how soil microbes regulate carbon (C) emissions in forests, which support the largest soil carbon stocks globally. Using metagenomic sequencing and ¹³ C-glucose, we provide unprecedented evidence that microbial traits explain a unique portion of the variation in soil priming across forest biomes from tropical to cold temperature regions. We show that microbial functional profiles associated with the degradation of labile C, especially rapid simple sugar metabolism, drive soil priming in different forests. Genes involved in the degradation of lignin and aromatic compounds were negatively associated with priming effects in temperate forests, whereas the highest level of soil priming was associated with β-glucosidase genes in tropical/subtropical forests. Moreover, we reconstructed, for the first time, 42 whole bacterial genomes associated with the soil priming effect and found that these organisms support important gene machinery involved in priming effect. Collectively, our work demonstrates the importance of microbial traits to explain soil priming across forest biomes and suggests that rapid carbon metabolism is responsible for priming effects in forests. This knowledge is important because it advances our understanding on the microbial mechanisms mediating soil-climate feedbacks at a continental scale.

Responses of AM fungal abundance to the drivers of global climate change: A meta-analysis

Arbuscular mycorrhizal fungi (AMF), playing critical roles in carbon cycling, are vulnerable to climate change. However, the responses of AM fungal abundance to climate change are unclear. A global-scale meta-analysis was conducted to investigate the response patterns of AM fungal abundance to warming, elevated CO₂ concentration (eCO₂), and N addition. Both warming and eCO₂ significantly stimulated AM fungal abundance by 18.6% (95%CI: 5.9%-32.8%) and 21.4% (15.1%-28.1%) on a global scale, respectively. However, the response ratios (RR) of AM fungal abundance decreased with the degree of warming while increased with the degree of eCO₂. Furthermore, in warming experiments, as long as the warming exceeded 4 °C, its effects on AM fungal abundance changed from positive to negative regardless of the experimental durations, methods, periods, and ecosystem types. The effects of N addition on AM fungal abundance are -5.4% (-10.6%-0.2%), and related to the nitrogen fertilizer input rate and ecosystem type. The RR of AM fungal abundance is negative in grasslands and farmlands when the degree of N addition exceeds 33.85 and 67.64 kg N ha^-1 yr^-1, respectively; however, N addition decreases AM fungal abundance in forests only when the degree of N addition exceeds 871.31 kg N ha^-1 yr^-1. The above results provide an insight into predicting ecological functions of AM fungal abundance under global changes.

[Screening of drugs that selectively inhibit uveal melanoma cells with SF3B1 mutations]

OBJECTIVE

To screen compounds that can selectively inhibit uveal melanoma cells with splicing factor 3B subunit 1 (SF3B1) mutations in comparison with isogenic SF3B1 wild-type counterparts in a cell model of SF3B1 mutant allele knockout.

METHODS

Principal component analysis was used to analyze transcriptome alternative splicing in TCGA cohorts of uveal melanoma with wild-type SF3B1 and SF3B1 mutations, and abnormal alternative splicing events derived from SF3B1 mutations were identified. The SF3B1 mutant allele in Mel202 cells was knocked out using CRISPR-Cas9 technology, and Sanger sequencing was used to verify the edited sequence. MTT and colony formation assays were used to assess the proliferation of Mel202 and Mut-KO cells. RT-PCR agarose electrophoresis combined with Sanger sequencing was used to determine alternative splicing events in Mel202 and Mut-KO cells. MTT assay was performed to screen the compounds that showed selective inhibitory effect against Mel202 cells with SF3B1 mutation.

RESULTS

Specific knockout of SF3B1 mutant allele in Mel202 cells obviously promoted the cell proliferation and caused changes in alternative splicing of ZDHHC16 and DYNLL1 transcripts. The screening data showed that 13 compounds had selective inhibitory activity against Mel202 cells with SF3B1 mutation (Fold change≥2), and among them, tetrandrine and lapatinib showed good dose-effect curves.

CONCLUSION

This study provides a cell screening model for identification of potential individualized treatment drugs for patients with uveal melanoma with SF3B1 mutation.

Whole-lesion histogram analysis of mono-exponential and bi-exponential diffusion-weighted imaging in differentiating lung cancer from benign pulmonary lesions using 3 T MRI

AIM

To investigate whether whole-lesion histogram analysis of apparent diffusion coefficient (ADC) values derived from mono-exponential and bi-exponential diffusion-weighted imaging (DWI) can differentiate lung cancer from benign pulmonary lesions.

MATERIALS AND METHODS

Thirty-two patients with lung cancer and 17 patients with benign pulmonary lesions were included retrospectively. All patients underwent DWI before surgery or biopsy. ADC histogram parameters, including mean, percentile values (10^th and 90^th), kurtosis, and skewness, were calculated independently by two radiologists. The histogram parameters were compared between patients with lung cancer and benign lesions. Receiver operating characteristic curves were constructed to evaluate the diagnostic performance.

RESULTS

The ADC_Mean, ADC_10th, D_Mean, D_10th were significantly lower in lung cancer (1.187 ± 0.144 × 10^-3; 0.440 ± 0.062 × 10^-3; 1.068 ± 0.108 × 10^-3; and 0.422 ± 0.049 × 10^-3 mm/s) compared to benign lesions (1.418 ± 0.274 × 10^-3; 0.555 ± 0.113 × 10^-3; 1.216 ± 0.149 × 10^-3; and 0.490 ± 0.044 × 10^-3 mm/s; p<0.05). The ADC_Skewness and D_Skewness were significantly different between lung cancer (2.35 ± 0.72; 2.58 ± 1.14) and benign lesions (1.85 ± 0.54; 1.59 ± 1.47; p<0.05). D_10th was robust in differentiating lung cancer from benign lesions. Using 0.453 × 10^-3 mm/s as the optimal threshold, the sensitivity, specificity, and accuracy of D_10th were 78.12%, 82.35%, and 79.6%, respectively.

CONCLUSION

Whole-lesion histogram analysis of ADC values derived by mono-exponential and bi-exponential DWI using 3 T magnetic resonance imaging helps distinguish lung cancer from benign pulmonary lesions.

Pump-depletion dynamics and saturation of stimulated Brillouin scattering in shock ignition relevant experiments

As an alternative inertial confinement fusion scheme, shock ignition requires a strong converging shock driven by a high-intensity laser pulse to ignite a precompressed fusion capsule. Understanding nonlinear laser-plasma instabilities is crucial to assess and improve the laser-shock energy coupling. Recent experiments conducted on the OMEGA EP laser facility have demonstrated that such instabilities can ∼100% deplete the first 0.5 ns of the high-intensity laser. Analyses of the observed laser-generated blast wave suggest that this pump-depletion starts at ∼0.02 critical density and progresses to 0.1-0.2 critical density, which is also confirmed by the time-resolved stimulated Raman backscattering spectra. The pump-depletion dynamics can be explained by the breaking of ion-acoustic waves in stimulated Brillouin scattering. Such pump depletion would inhibit the collisional laser energy absorption but may benefit the generation of hot electrons with moderate temperatures for electron shock ignition [Phys. Rev. Lett. 119, 195001 (2017)PRLTAO0031-900710.1103/PhysRevLett.119.195001].

Focus on autonomic dysfunctions in anti-NMDAR encephalitis: a case report

OBJECTIVE

We hope it will provide a reference for early detection, early diagnosis, and early treatment of atypical Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis with non-typical autonomic dysfunctions as the first symptom.

PATIENTS AND METHODS

We present a 15-year-old girl with the repetition of conscious disturbance at different levels, but no abnormal movements. Initially, there were no positive findings on routine electroencephalography (EEG) and dynamic video-electroencephalography (V-EEG), but the head-up tilt test (HTT) suggested neurocardiogenic syncope (vascular rejection type), which seemed to be the final diagnosis. However, the patient later experienced several episodes of disturbance of consciousness with unexplained abdominal pain. Abnormalities were discovered on EEG, which indicated the possibility of "epileptic seizures with autonomic-gastrointestinal features". Based on these findings, we finally tested the autoimmune encephalitis-related antibodies for the patient after the literature search and review.

RESULTS

The patient was finally diagnosed with anti-NMDAR encephalitis. Her symptoms were fully controlled after glucocorticoid and gamma globulin treatment, and she left the hospital with complete recovery.

CONCLUSIONS

Although autonomic nervous dysfunction occurred in our patient, her prognosis was good because she did not have respiratory or (and) circulatory failure. Exclusive diagnosis and early treatment are important in patients with anti-NMDAR encephalitis. Abdominal pain with positive HTT may be a manifestation of autonomic dysfunction in this disease.

[Correlation between alcohol drinking and high risk sexual behaviors in HIV negative clients of female sex workers]

Objective: To explore the correlation between alcohol drinking and high-risk sexual behaviors in HIV negative clients of female sex workers and provide scientific evidence for prevention of HIV sexual transmission. Methods: A cross-sectional survey was conducted in HIV negative clients in Ji'nan and Haikou from December 2018 to May 2019. The estimated sample size was 337, the information about their demographic characteristics, AIDS knowledge awareness, sexual behaviors and alcohol drinking habit were collected through convenience sampling. The data were analyzed by using SPSS 24.0 software. Results: A total of 381 clients were included in this study. Most of them were less than 40 years old, accounting for 89.2% (340/381); 85.3% of them (325/381) reported an education level of high school and above; the clients who were married, had cohabitation with females or had girl friends accounted for 53.2% (202/380). The overall awareness rate of AIDS knowledge was 83.7% (318/380). Of all participants, 80.8% (308/381) had commercial sex in the past year, 79.8% (304/381) had non-commercial sex partners, 62.7% (239/381) had high-risk sexual behaviors. The results of logistic regression showed that compared with those with alcohol drinking frequency ≤2 times per month in last year, the clients with alcohol drinking frequency more than once a week (aOR=3.22, 95%CI: 1.25-8.27) were more likely to have high risk sexual behaviors after adjustment for age, living area, location type of residence, time of local residence, education level, monthly income level, occupation, marital status, knowledge awareness of AIDS and HIV related services, the number of commercial or non-commercial sexual partners in the past year, cost of commercial sex and HIV test frequency. Conclusions: Alcohol drinking is related to high risk sexual behaviors in HIV negative clients, and will increase the risk of HIV transmission. To control AIDS, the intervention of alcohol drinking should be combined with other preventions to improve the correct use of condoms.

[Influence of Xuebijing injection and its component paeoniflorin on immune function and survival rate of septic rats]

Objective: To explore the influence of Xuebijing injection (hereinafter referred to as Xuebijing) and its component paeoniflorin on immune function of regulatory T cells (Tregs) of spleen and survival rate of septic rats. Methods: (1) CD4(+) CD25(+) Tregs and CD4(+) T cells were isolated and purified from spleens of three 9 to 12 weeks old Sprague-Dawley male rats (the same age, breed, and gender below) by immunomagnetic beads. According to the random number table (the same grouping method below), CD4(+) CD25(+) Tregs were divided into blank control group, simple CD3/CD28 group, simple endotoxin/lipopolysaccharide (LPS) group, LPS+ Xuebijing group, and LPS+ paeoniflorin group, with 6 wells in each group. The cells in simple CD3/CD28 group, simple LPS group, LPS+ Xuebijing group, and LPS+ paeoniflorin group were cultured in RPMI 1640 medium containing fetal bovine serum in volume fraction of 10%, 1.25 μg CD3, and 2.5 μg CD28 for 24 hours. Then 1 μg/mL LPS in the volume of 1 μL was added to the cells in simple LPS group, LPS+ Xuebijing group, and LPS+ paeoniflorin group. Moreover, 5 mg/mL Xuebijing in the volume of 1 μL and 80 μmol/L paeoniflorin in the volume of 1 μL were added to the cells in LPS+ Xuebijing group and LPS+ paeoniflorin group, respectively, which were cultured for another 72 hours. Cells in blank control group were routinely cultured in RPMI 1640 medium containing fetal bovine serum in volume fraction of 10% for 96 hours. The expressions of cytotoxic T lymphocyte antigen 4 (CTLA-4) and forkhead wing-link transcription factor 3 (Foxp3) and apoptosis of CD4(+) CD25(+) Tregs were measured by flow cytometry. The interleukin-10 (IL-10) level from culture supernatant of CD4(+) CD25(+) Tregs was determined by enzyme-linked immunosorbent assay (ELISA). CD4(+) T cells were divided into blank control' group, simple CD3/CD28' group, simple LPS' group, LPS+ Xuebijing' group, and LPS+ paeoniflorin' group, with 6 wells in each group. After being cocultured with the corresponding CD4(+) CD25(+) Tregs treated as before for 72 hours, the proliferative activity of CD4(+) T cells was measured by flow cytometry, and IL-4 level from culture supernatant of CD4(+) T cells was determined by ELISA. (2) One hundred and twenty rats were divided into sham surgery group, simple sepsis group, sepsis+ Xuebijing group, and sepsis+ paeoniflorin group, with 30 rats in each group. The septic rat model was reproduced by cecal ligation and puncture surgery in simple sepsis group, sepsis+ Xuebijing group, and sepsis+ paeoniflorin group. In sham surgery group, the rats were only performed with laparotomy to simulate surgery. In sepsis+ Xuebijing group, the rats were given post-surgical injection of 4 mL/kg Xuebijing through tail vein, twice a day. In sepsis+ paeoniflorin group, the rats received 978 μg paeoniflorin via tail vein, twice a day. The survival rates of rats in the four groups on post surgery day 1, 2, 3, 4, 5, 6, and 7 were observed and recorded. The surviving cure of Kaplan-Meier was drawn. Data were statistically analyzed with one-way analysis of variance, least significant difference t test. The surviving curve was analyzed by Log-rank (Mantel-Cox) test. Results: (1) Compared with those in blank control group, the expressions of CTLA-4 and Foxp3 of CD4(+) CD25(+) Tregs (t=27.19, 17.00, P<0.01) and IL-10 level from culture supernatant (t=40.76, P<0.01) were significantly increased in rats in simple LPS group. Compared with those in simple LPS group, the expressions of CTLA-4 and Foxp3 of CD4(+) CD25(+) Tregs (t(LPS+ Xuebijing group)=31.03, 11.27, t(LPS+ paeoniflorin group)=5.79, 5.64, P<0.01) and IL-10 level from culture supernatant (t=15.49, 4.20, P<0.01) was significantly decreased in LPS+ Xuebijing group and LPS+ paeoniflorin group. Compared with that in blank control group, the apoptosis rate of CD4(+) CD25(+) Tregs in simple LPS group was significantly declined (t=6.02, P<0.01). Compared with the rate in simple LPS group, the apoptosis rates of CD4(+) CD25(+) Tregs in LPS+ Xuebijing group and LPS+ paeoniflorin group were significantly increased (t=20.32, 8.60, P<0.01). (2) Compared with those in simple CD3/CD28' group, the proliferative rate of CD4(+) T cells was significantly decreased in simple LPS' group (t=22.47, P<0.01), while IL-4 level from culture supernatant was significantly elevated (t=3.51, P<0.01). Compared with those in simple LPS' group, the proliferative rates of CD4(+) T cells in LPS+ Xuebijing' group and LPS+ paeoniflorin' group were significantly increased (t=16.31, 11.48, P<0.01), while IL-4 level from culture supernatant showed no obvious change. (3) The post-operative 7-day survival rates of rats in sham surgery group, simple sepsis group, sepsis+ Xuebijing group, sepsis+ paeoniflorin group were 100% (30/30), 30% (9/30), 57% (17/30), and 47% (14/30), respectively. Compared with that in simple sepsis group, the survival rate within post-operative 7-day of rats in sepsis+ Xuebijing group was significantly higher (χ(2)=4.34, P<0.05), while the survival rate within post-operative 7-day of rats in sepsis+ paeoniflorin group showed no obvious change. Conclusions: Both Xuebijing and its component paeoniflorin are capable of reversing sepsis-induced inhibitory immune function and apoptotic resistant of Tregs in rats, and further improving the proliferative activity of T cells. In addition, the effect of paeoniflorin on improvement of survival rate of rats with sepsis is weaker than Xuebijing.

Contrasting Responses of Rhizosphere Bacteria, Fungi and Arbuscular Mycorrhizal Fungi Along an Elevational Gradient in a Temperate Montane Forest of China

Elevational gradients strongly affect microbial biodiversity in bulk soil through altering plant and soil properties, but the effects on rhizosphere microbial patterns remain unclear, especially at large spatial scales. We therefore designed an elevational gradient experiment to examine rhizosphere microbial (bacteria, fungi and arbuscular mycorrhizal fungi) diversity and composition using Illumina sequencing of the 16S rRNA and ITS genes for comparison to plant and soil properties. Our results showed that bacterial and fungal alpha diversity was significantly higher at mid-elevation, while AMF alpha diversity decreased monotonically. The beta diversities of the three groups were significantly affected by elevational gradients, but the effect on bacterial beta diversity was larger than on fungal and AMF beta diversity. Proteobacteria, the dominant phyla of bacteria, was significantly higher at the mid-elevation, while Acidobacteria and Actinobacteria significantly decreased as elevation increased. The main fungal taxa, Basidiomycota, significantly decreased with elevation, and Ascomycota significantly increased with elevation. Glomeromycota, the dominant AMF phyla, responded insignificantly to the elevational gradients. The responses of bacterial and fungal alpha diversity were mostly associated with tree diversity and organic carbon, whereas AMF alpha diversity mainly depended on litter N and P. Changes in bacterial community composition along the elevational gradient were explained primarily by litter N and P, and litter P was the main driver of fungal and AMF community composition. Overall, our results suggest that plant litter, particularly litter N and P, were the main source of external carbon input and drove the observed differences in rhizosphere microbial diversity and community composition. Our results highlight the importance of litter nutrition in structuring rhizosphere microbial communities in mountain ecosystems.

Effects of Robinia pseudoacacia afforestation on aggregate size distribution and organic C dynamics in the central Loess Plateau of China: A chronosequence approach

Afforestation has been proven to have enormous potential for carbon (C) sequestration; however, the dynamics of aggregate-associated organic carbon (OC) following afforestation and their contribution to changes in bulk soil OC are not well understood in regions with serious soil erosion. Therefore, we investigated the dynamics of OC associated with aggregates along a Robinia pseudoacacia (RP) afforestation chronosequence in the Loess Plateau. Soil aggregate size distribution and OC dynamics in bulk soil were analyzed 10, 18, 28, and 42 years after RP afforestation at depths of 0-20 cm and 20-40 cm. Results showed that total macroaggregates (>0.25 mm), mean weight diameter, and geometric mean diameter increased significantly with stand age, after 42 years of afforestation, increased by 433.5%, 437.2%, 302.1% in the 0-20 cm depth, respectively, while microaggregate amounts decreased by 52.9%, and the proportions of silt + clay fraction showed no obvious changes. Long-term afforestation increased OC content and stock, both in bulk soil (245.6% and 222.9% in the 0-20 cm depth, respectively) and soil aggregates. The improvement of soil structure and enrichment of OC stocks were greater at the 0-20 cm depth than the 20-40 cm depth. In addition, small macroaggregates (2-0.25 mm) contained the highest OC content and microaggregates (<0.025 mm) had the highest OC stocks regardless of soil depth and stand age. Across the afforestation chronosequence, OC content and stock in bulk soil positively correlated with large macroaggregate (>2 mm) amounts and small macroaggregate (2-0.25 mm) associated OC dynamics (P < 0.01). These results indicated that changes in bulk soil OC dynamics mainly depend on changes in the proportion of large macroaggregates and in the OC dynamics associated with small macroaggregates after RP afforestation.

Cogeneration of hot electrons from multiple laser-plasma instabilities

Interactions of two-plasmon decay (TPD) and side-stimulated Raman scattering (SSRS) were studied using three-dimensional particle-in-cell simulations under inertial-confinement-fusion-relevant conditions for linearly and circularly polarized lasers. In the linear stage, SSRS took place under n_{e}=0.235n_{c} and TPD dominated near the quarter-critical density surface and their growth rates agreed with theory. In the nonlinear stage, SSRS reduced TPD through pump depletion. Hot electrons were found to be first accelerated by SSRS plasma waves and then by TPD plasma waves through a cogeneration mechanism. Compared to the linearly polarized case with the same laser intensity, both SSRS and TPD were reduced due to the lower laser amplitude in the circularly polarized case. As a result, a 30% decrease in hot electron flux was observed.

Differential responses of soil hydrolytic and oxidative enzyme activities to the natural forest conversion

Effects of natural forest conversion (NFC) on soil nutrient turnover are substantially mediated by soil microbial extracellular hydrolytic enzymatic activities (Hy-EEAs) and oxidative enzymatic activities (Ox-EEAs). Yet it remains largely unknown the indicative links between soil Hy- and Ox-EEAs and soil carbon (C), nitrogen (N) and phosphorus (P) supplies based on economic theories of microbial metabolism under NFC. Here we used a meta-analysis approach to synthesize the responses of the soil C-, N-, P-degrading Hy-EEAs and Ox-EEAs, soil microbial biomass, soil organic C, total N, P and available P parameters to natural forest conversion from 51 peer-reviewed studies. Our results showed that NFC notably decreased soil Hy-EEAs but statistically insignificant reduction of soil Ox-EEAs. The changes of soil Hy- and Ox-EEAs were significantly and positively associated with soil organic C, available P as well as microbial biomass C and N but significantly and negatively correlated with soil pH, whereas the changes of soil C/N impacted on soil Ox-EEAs remarkably but not for soil Hy-EEAs. The depletion of soil organic carbon stimulated soil microbial secretion of Hy- and Ox-EEAs. The soil total N scarcity only provoked soil microbial Hy-EEAs rather than Ox-EEAs. The soil total P dearth quickened the soil Ox-EEAs, however, the plenitude of soil available P suppressed soil Hy- and Ox-EEAs. Moreover, the eco-enzymatic stoichiometry of soil Hy-EEAs indicated that soil N and P nutrient limitation after NFC restricted soil microbial N- and P-acquiring enzymes secretion, which ultimately reduced resources availability for C acquisition. Altogether, the distinct responses of soil Hy- and Ox-EEAs depended on substrate availability peculiarly for soil N and P gains of microorganisms for further enzymatic ability on soil C decomposition and highlighted the abundant or absent supply of soil N and P for positive or negative enzymatic activities on metabolic requirement of soil edaphons.

miR-27a is an important adipogenesis regulator associated with differential lipid accumulation between intramuscular and subcutaneous adipose tissues of sheep

Micro ribonucleic acids (miRNAs) are crucial regulators for various biological processes. Despite important function in the proliferation and differentiation of preadipocytes, miRNA studies are limited in regional differences in adipogenesis. Here, we show that miR-27a plays an important role in regulating differential lipid accumulation between intramuscular (IM) and subcutaneous (SC) adipose tissues in sheep. Invivo, we observed that miR-27a expression in IM adipose tissue is more abundant than in SC adipose tissue. However, the expression of Peroxisome Proliferator-Activated Receptor Gamma (PPARG) and retinoid X receptor alpha (RXR alpha) in IM adipose tissue was significantly lower than that in SC adipose tissue. In the ovine preadipocyte differentiation model, we found that the expression of miR-27a was significantly decreased in differentiated ovine adipocytes. Overexpression of miR-27a significantly downregulated the expression of PPARG and RXR alpha and suppressed the accumulation of triglyceride but promoted the proliferation of ovine preadipocytes. Whereas, inhibition of miR-27a suppressed preadipocyte proliferation but enhanced PPARG and RXR alpha expression and lipid droplet formation. In addition, dual-luciferase activity assays showed that RXR alpha was a direct target of miR-27a. Thus, miR-27a enhances ovine preadipocytes proliferation and inhibits ovine preadipocytes differentiation through regulating the expression of target RXR alpha. Collectively, our study demonstrates the functional importance of miR-27a in ovine adipogenesis and provides novel insights into exploring regional differences in adipogenesis.

Pump depletion and hot-electron generation in long-density-scale-length plasma with shock-ignition high-intensity laser

Two-dimensional particle-in-cell simulations for laser plasma interaction with laser intensity of 10^{16}W/cm^{2}, plasma density range of 0.01-0.28n_{c}, and scale length of 230-330μm showed significant pump depletion of the laser energy due to stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) in the low-density region (n_{e}=0.01-0.2n_{c}). The simulations identified hot electrons generated by SRS in the low-density region with moderate energy and by two-plasmon-decay near n_{e}=0.25n_{c} with higher energy. The overall hot electron temperature (46 keV) and conversion efficiency (3%) were consistent with the experiment's measurements. The simulations also showed artificially reducing SBS would lead to stronger SRS and a softer hot-electron spectrum.

[Effects of ticagrelor on cardiorespiratory fitness in patients after percutaneous coronary intervention]

Objective: To investigate the effects of ticagrelor on cardiorespiratory fitness in patients with coronary heart disease after percutaneous coronary intervention (PCI). Methods: A total of 1 073 patients, who were diagnosed as coronary heart disease and underwent cardiopulmonary exercise testing (CPET) within 1 year after PCI, were enrolled from September 2017 to September 2019 in Peking University Third Hospital, including 309 patients in ticagrelor group and 764 patients in clopidogrel group. Clinical information, blood test results, echocardiographic parameters, cardiorespiratory fitness related parameters (including peak oxygen uptake (VO(2)), anaerobic threshold VO(2), peak oxygen pulse (VO(2)/HR) and carbon dioxide ventilation equivalent (VE/VCO(2)) slope), coronary lesions and intervention information were obtained. Cardiopulmonary fitness related indexes were compared between the two groups, and the correlation between ticagrelor use and cardiopulmonary fitness related indexes was analyzed by multivariate logistic regression. Patients who underwent CPET within 1 month after PCI were included in the subgroup analysis. Results: In ticagrelor group, the age was (60.3±10.3) years, and 253(81.9%) cases were male. The age of clopidogrel group was (60.6±10.0) years, and there were 608(79.6%) males. No significant differences were observed in peak VO(2), anaerobic threshold VO(2), and peak VO(2)/HR between the two groups (all P>0.05), but the VE/VCO(2) slope was significantly higher in the ticagrelor group than in the clopidogrel group (30.075 (27.207, 33.603) vs. 28.853 (25.970, 32.336), P<0.001). Logistic regression analysis suggested that the peak VO(2), anaerobic threshold VO(2) and peak VO(2)/HR were not significantly correlated with the ticagrelor use (all P>0.05), while the VE/VCO(2) slope was independently correlated with ticagrelor use (OR=1.098, 95%CI 1.032-1.168, P=0.003). Subgroup analysis of patients who underwent CPET within 1 month after PCI also indicated that no significant difference were observed in peak VO(2), anaerobic threshold VO(2), peak VO(2)/HR and VE/VCO(2) slope between the two groups (all P>0.05). Logistic regression analysis suggested that the peak VO(2), anaerobic threshold VO(2) and peak VO(2)/HR were not significantly correlated with ticagrelor use (all P>0.05), while the VE/VCO(2) slope was significantly correlated with ticagrelor use (OR=1.132, 95%CI 1.030-1.244, P=0.010). Conclusion: Among coronary heart disease patients after PCI, treatment with clopidogrel does not result in significant decrease in exercise endurance as compared with patients treated with ticagrelor.

Dynamics of bacterial community in litter and soil along a chronosequence of Robinia pseudoacacia plantations

As the driver of plantation ecosystem function, microorganisms can decompose plant residues and soil organic matter. To identify dynamics of microbial communities in litter and soil and its influence by vegetation and soil at regional scales, the plantations of Robinia pseudoacacia at different successional stages (13, 19, 29, and 44 y) was selected on the Loess Plateau. High-throughput sequencing of the 16S rRNA gene was used to examine bacterial communities in litter and soil, and changes in vegetation, litter, and soil characteristics were analyzed. With increase of stand age, coverage and biomass of understory vegetation increased significantly and peaked at 44-y. Concentrations of carbon (C), nitrogen (N), and phosphorus (P) in litter and soil increased significantly, whereas pH values decreased significantly. Composition and diversity of bacterial communities in litter and soil were significantly different. Diversity and richness of litter bacterial communities were higher than that of soils. Relative abundances of Actinobacteria and Proteobacteria in litter were higher than that in soil; relative abundance of Acidobacteria exhibited the reverse trend. The diversity and richness index of vegetation significantly affected that of litter bacterial communities. Soil C/P significantly affected the Simpson and Shannon index of soil bacterial communities. The C/P and pH of litter and soil were significantly correlated with bacterial composition, primarily including Actinobacteria, Acidobacteria, and Gemmatimonadetes. Diversity of litter bacterial communities was more sensitive to the diversity and richness of vegetation flora than that of soil in the succession of R. pseudoacacia. Canopy density, vegetation, and litter and soil nutrients might directly or indirectly affect bacterial communities. Carbon, phosphorus, and pH may be critical factors influencing the composition of bacterial communities in litter and soil.

Serum sclerostin as a potential novel biomarker for heart valve calcification in patients with chronic kidney disease

OBJECTIVE

To explore the correlation between change in sclerostin level and heart valve calcification in patients with chronic kidney disease (CKD) in stages 3-5, as well as the possible underlying mechanism, which could provide a clinical reference for the diagnosis and treatment of cardiovascular disease (CVD).

PATIENTS AND METHODS

110 patients were divided into a healthy control group and three groups of patients with CKD stages 3, 4, and 5 according to CKD staging guidelines. Scr, BUN, AKP, TC, TG, HDL, LDL, Ca, Pi, and CRP were measured, and calcium-phosphate product (Ca×Pi) calculated. ELISA was used to measure the sclerostin level, and the estimated glomerular filtration rate (eGFR) was calculated by MDRD. Heart valve calcification was measured by a physician in the Cardiac Department of our hospital. The correlations between sclerostin-level change and heart valve calcification, as well as each index in CKD patients in stages 3-5, were analyzed.

RESULTS

Compared with the healthy control group, the serum Ca in CKD stage-3, stage-4, and stage-5 groups (p < 0.05) was reduced, and PTH was increased (p < 0.05). Blood Pi and Ca×Pi in the stage-4 and stage-5 groups were increased (p < 0.05). The serum sclerostin level increased with renal hypofunction in stage-3 CKD patients, and was significantly increased compared with that of the control group, reaching the highest level in the terminal stage (p < 0.01). Pearson correlation analysis indicated that serum sclerostin was negatively correlated with eGFR (r = -0.91, p < 0.001) and blood Ca (r= -0.271, p < 0.001), and positively correlated with SCr (r = 0.608, p < 0.001), blood Pi level (r = 0.295, p < 0.001), PTH (r = 0.334, p < 0.001), and Ca×Pi (r = 0.275, p < 0.001). The rate of heart valve calcification in the CKD patients in stage 5 was relatively high (11/30, 36.67%), and significantly higher than that in healthy controls (1/20, 5%; p < 0.01). Logistic regression analysis of heart valve calcification indicated that sclerostin was a risk factor for heart valve calcification in CKD patients in stages 3-5.

CONCLUSIONS

The sclerostin level gradually increased with renal hypofunction in CKD patients in stages 3-5, and the increase in serum sclerostin level in the CKD patients occurred earlier than the change in Pi and Ca×Pi. The risk of heart valve calcification in stage-5 CKD patients was significantly increased. Sclerostin is an independent risk factor for heart valve calcification in CKD patients.

Three-dimensional particle-in-cell modeling of parametric instabilities near the quarter-critical density in plasmas

The nonlinear regime of laser-plasma interactions including both two-plasmon decay (TPD) and stimulated Raman scattering (SRS) instabilities has been studied in three-dimensional (3D) particle-in-cell simulations with parameters relevant to the inertial confinement fusion (ICF) experiments. SRS and TPD develop in the same region in plasmas, and the generation of fast electrons can be described accurately with only the full model including both SRS and TPD. The growth of instabilities in the linear stage is found to be in good agreement with analytical theories. In the saturation stage the low-frequency density perturbations driven by the daughter waves of the SRS side scattering can saturate the TPD and consequently inhibit the fast-electron generation. The fast-electron flux in 3D modeling is up to an order of magnitude smaller than previously reported in 2D TPD simulations, bringing it close to the results of ICF experiments.

Diazoxide induces endoplasmic reticulum stress-related neuroprotection mediated by p38 MAPK against Aβ25-35 insults

OBJECTIVE

The endoplasmic reticulum (ER) -resident caspase-12 was identified as a mediator of Aβ neurotoxicity. Recent evidence indicates that mitochondrial ATP-sensitive potassium (KATP) channel openers mediate their neuroprotective role by adjusting ER stress pathways, but the molecular details remain largely unknown and have been investigated.

MATERIALS AND METHODS

In this study, the protein expression levels of calreticulin (CRT) and caspase-12 activation and phosphorylated p38 MAPK were observed by immunoblotting in cultured PC12 cells from different groups: treatment with Aβ25-35 (group Aβ25-35), treatment with diazoxide (group diazoxide), pretreatment with diazoxide and then exposure to Aβ25-35 (group diazoxide + Aβ25-35), pretreatment with p38 MAPK inhibitor SB 203580 and then exposure to diazoxide and Aβ25-35 (group SB 203580 + diazoxide + Aβ25-35), and the control (group control).

RESULTS

In response to the treatment with Aβ25-35 (10 µM) for 24 h, the protein expression levels of CRT and caspase-12 activation were increased and phosphorylated p38 MAPK was decreased significantly. Diazoxide reduced CRT overexpression and caspase-12 activation and increased the up-regulation of phosphorylated p38 MAPK. When SB 203580 was presented before exposure to diazoxide and Aβ25-35, CRT expression was markedly suppressed, and the inhibition effect of diazoxide on caspase-12 activation was almost eliminated.

CONCLUSIONS

We showed that diazoxide induced ERS-related neuroprotection mediated by p38 MAPK against Aβ25-35 insults. From the clinical point of view, these results are of considerable importance for the understanding of AD pathogenesis. However, further studies are required to explore more detailed mechanisms of the observed effects.

[Influence of vagus nerve on multiple organ function and immune reaction of T lymphocytes in septic rats]

Objective: To explore influence of vagus nerve on multiple organ function and immune reaction of T lymphocytes in septic rats. Methods: Forty Sprague-Dawley rats were divided into sham injury group, sepsis group, vagus nerve stimulation (VNS) group, and vagotomy (VGX) group, according to the random number table, with 10 rats in each group. Rats in sepsis group, VNS group, and VGX group were inflicted with sepsis by cecal ligation and puncture (CLP). Rats in VNS group were given electrical stimulation on left cervical vagus nerve for 15 min right after CLP. Rats in VGX group underwent vagotomy of left cervical vagus nerve at 30 min before CLP. At 24 h after CLP, serum of rats was collected to detect levels of alanine transaminase (ALT), aspartate aminotransferase (AST), glycocholic acid (CG), creatine kinase (CK), myocardial creatine kinase (CK-MB), blood urea nitrogen (BUN), and serum creatinine by fully automatic biochemistry analyzer. The left lung of rats was collected to determine wet or dry mass, and wet to dry (W/D) ratio was calculated. The right lung of rats was collected to measure the activity of pulmonary myeloperoxidase (MPO) by enzyme linked immunosorbent assay (ELISA). Spleen of rats was collected to determine the proliferative activity of CD4(+) T lymphocytes by cell counting kit 8, and real-time fluorescence quantitative polymerase chain reaction and ELISA were used to quantify mRNA expressions and levels of interleukin 2 (IL-2), interferon-γ, and IL-4, respectively. Data were processed with one-way analysis of variance and Tukey's honest significant difference test. Results: (1) The levels of serum ALT, AST, CG, CK, CK-MB, BUN, and creatinine, pulmonary W/D ratio, as well as MPO activity of rats in sepsis group were significantly higher than those in sham injury group and VNS group (P<0.01) and were significantly lower than those in VGX group (P<0.01). (2) The proliferative activity of CD4(+) T lymphocytes of rats in sepsis group was 0.93±0.03, which was significantly lower than 1.54±0.07 of rats in sham injury group (P<0.01). The proliferative activity of CD4(+) T lymphocytes of rats in VNS group was 1.15±0.15, which was significantly higher than that of rats in sepsis group (P<0.01). The proliferative activity of CD4(+) T lymphocytes of rats in VGX group was 0.75±0.06, which was obviously lower than that of rats in sepsis group (P<0.01). (3) In comparison with those of rats in sham injury group, the levels of IL-2 and interferon-γ in CD4(+) T lymphocytes of rats in sepsis group were markedly decreased (P<0.01), while the level of IL-4 was significantly increased (P<0.01). In comparison with those of rats in sepsis group, the levels of IL-2 and interferon-γ in CD4(+) T lymphocytes of rats in VNS group were obviously increased (P<0.01), while the level of IL-4 was markedly decreased (P<0.01). As compared with those of rats in sepsis group, the levels of IL-2 and interferon-γ in CD4(+) T lymphocytes of rats in VGX group were markedly decreased (P<0.01), while the level of IL-4 was significantly increased (P<0.01). (4) As compared with those of rats in sham injury group, expressions of IL-2 and interferon-γ mRNA in CD4(+) T lymphocytes of rats in sepsis group were markedly decreased (P<0.01), while expression of IL-4 mRNA was significantly increased (P<0.01). Expressions of IL-2 and interferon-γ mRNA in CD4(+) T lymphocytes of rats in VNS group were obviously increased when compared with those of rats in sepsis group (P<0.01), while expression of IL-4 mRNA was markedly decreased (P<0.01). In comparison with those of rats in sepsis group, expressions of IL-2 and interferon-γ mRNA in CD4(+) T lymphocytes of rats in VGX group were markedly decreased (P<0.01), while expression of IL-4 mRNA was significantly increased (P<0.01). Conclusions: Electrical stimulation of vagus nerve can significantly improve multiple organ dysfunction and reverse immunosuppression of T lymphocytes in septic rats, while vagotomy of vagus nerve may enhance the susceptibility of rats to sepsis.

[Relationship between angiopoietin-2 and vascular endothelial factor and vasodilation function in hypertensive patients]

Objective: To analyze the relationship between angiopoietin 2 (Ang2) and vascular endothelial factor and vasodilation function in hypertensive patients. Methods: Patients with new onset grade 1~2 hypertension (n=40) and healthy control group (n=25) wereenrolledprospectively. Serum Ang2 and nitric oxide (NO), nitric oxide synthase (eNOS), endothelin-1 (ET-1) were measured in both groups. Flow-mediated vasodilation (FMD) were measured in hypertensive patients. The above indicators were reviewed in hypertensive patients after antihypertensive treatment until blood pressure<140/90 mmHg. Results: Compared with the control group, serum Ang2 (P=0.049) and ET-1 (P<0.001) were significantly higher. Serum NO (P<0.001) and eNOS (P<0.001) was significantly lower in the hypertensive group. Compared with baseline, serum Ang2 (P=0.049) and ET-1 (P<0.001) were decreased significantly, meanwhile serum NO (P<0.001) and eNOS (P<0.001) were significantly increased. Serum Ang2 after antihypertensive treatment was not significantly different from that of the control group, but no statistical difference was observed in FMD after antihypertensive therapy. Correlation analysis found that serum Ang2 was positively correlated with mean arterial pressure (R=0.432, P<0.001), and negative correlated with serum NO(R=-0.374, P=0.001) and FMD (R=-0.368 0, P=0.002). Multiple linear regression found that serum Ang2 was independently associated with body mass index, mean arterial pressure, and serum NO. Conclusion: Serum Ang 2 can reflect the degree of endothelial and vasodilation impairment in hypertensive patients. Antihypertensive therapy can improve endothelial function, but whether it can restore damaged vasodilation function needs further verification.

Abstract P5-04-25: Characterization of FGFR1/2 genetic alterations reveals novel fusions of FGFR1 in Chinese breast cancer

Background: Deregulation of fibroblast growth factor receptor 1 (FGFR1) signalling has been extensively studied in various tumor types, and has been implicated in driving endocrine resistance in breast cancer. Genetic alterations of FGFR1, especially FGFR1 amplification, is one of particularly important mechanisms leading to enhanced FGFR signaling in breast cancer. However, the prevalence of FGFR1/2 genetic variations in Chinese breast cancer patients has not been well explored.

Methods: To investigate the characteristics of FGFR1 and FGFR2 genetic variations in Chinese breast cancer, we employed customized next-generation sequencing panel to screen the somatic mutation or copy number variations of FGFR1/2 in primary breast cancer tissues by using two ongoing breast cancer Cohorts, in which we have recruited 289 of early breast cancer patients (EBC Cohort) and 74 of advanced breast cancer patients (ABC Cohort).

Results: In EBC Cohort, we found FGFR1 amplification in 9.0% (26/289) patients and FGFR2 amplification in 2.1% (6/289) patients, and also found 3 of somatic FGFR1 mutations (FGFR1 p.W4C; p.E334K; p.V396I ) and 2 of FGFR2 mutations (FGFR2 p.S702L; p.Y779*). Unlike the comparable prevalence of FGFR2 genetic variations in 2.8% (8/289) of EBC Cohort and 2.7% (2/74; one amplification event and one FGFR2 p.E499D mutation) of ABC Cohort, there were more FGFR1 genetic alterations in ABC Cohort (27%; 20/74 patients; p&lt;0.001), including 19 events of FGFR1 amplification and 1 of FGFR1 c.2186+20G&gt;A intron mutation. More importantly, we identified 5 novel FGFR1 fusion genes in our cohorts, including TACC1-FGFR1, FGFR1-KCNU1, FGFR1-MIR1268A, FGFR1-LZTS1-AS1 and FGFR1-RNF5P1. Although FGFR1-TACC1 fusion gene has been previously reported in breast cancer and TACC1 is fused to the C-terminal of FGFR1 protein leading to aberrant activation of FGFR1, we found TACC1 was fused to the N-terminal of FGFR1 at exon 6 of FGFR1 in our study. In addition, we identified and verified FGFR1-MIR1268A fusion gene at mRNA level using RNA-seq analysis, and further found this fusion gene might result in the truncation of FGFR1.

Conclusions: Collectively, we characterized the prevalence of FGFR1/2 genetic alterations in Chinese breast cancer, and identified 5 of novel FGFR1 fusion genes. The potential roles for novel FGFR1 fusion genes in regulating breast cancer cellular biology and in affecting the efficacy of endocrine therapy have been under the investigation in our laboratory, and the result from which will help us better elucidate the molecular mechanism of FGFR1 in driving the resistance of endocrine therapy.

This study was supported by funding from National Natural Science Foundation of China (Grant No. 81602645), Guangdong Provincial Natural Science Foundation (Grant No. 2016A030313768) and Research Funds from Guangzhou Science and Technology Bureau (Grant No. 201707010418 and 201804010430).

Citation Format: Wang Y, Guo L, Cao L, Jia M, Wen L, Ren C, Zhang G, Liao N. Characterization of FGFR1/2 genetic alterations reveals novel fusions of FGFR1 in Chinese breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-04-25.