Longitudinal virological changes and underlying pathogenesis in hospitalized COVID-19 patients in Guangzhou,China

Science China Life Sciences - Prolonged viral RNA shedding and recurrence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in coronavirus disease 2019 (COVID-19) patients have been...     

Landscape genetic structure of Scirpus mariqueter reveals a putatively adaptive differentiation under strong gene flow in estuaries

Estuarine organisms grow in highly heterogeneous habitats, and their genetic differentiation is driven by selective and neutral processes as well as population colonization history. However, the relative importance of the processes that underlie genetic structure is still puzzling. Scirpus mariqueter is a perennial grass almost limited in the Changjiang River estuary and its adjacent Qiantang River estuary. Here, using amplified fragment length polymorphism (AFLP), a moderate‐high level of genetic differentiation among populations (range F_ST: 0.0310–0.3325) was showed despite large ongoing dispersal. FLOCK assigned all individuals to 13 clusters and revealed a complex genetic structure. Some genetic clusters were limited in peripheries compared with very mixing constitution in center populations, suggesting local adaptation was more likely to occur in peripheral populations. 21 candidate outliers under positive selection were detected, and further, the differentiation patterns correlated with geographic distance, salinity difference, and colonization history were analyzed with or without the outliers. Combined results of AMOVA and IBD based on different dataset, it was found that the effects of geographic distance and population colonization history on isolation seemed to be promoted by divergent selection. However, none‐liner IBE pattern indicates the effects of salinity were overwhelmed by spatial distance or other ecological processes in certain areas and also suggests that salinity was not the only selective factor driving population differentiation. These results together indicate that geographic distance, salinity difference, and colonization history co‐contributed in shaping the genetic structure of S. mariqueter and that their relative importance was correlated with spatial scale and environment gradient.     

Mitochondria bridge HIF signaling and ferroptosis blockage in acute kidney injury

Ferroptosis, a form of regulated cell death, plays an important role in acute kidney injury (AKI). Previous studies have shown that prolyl hydroxylase domain protein (PHD) inhibitors that activate HIF signaling provide strong protection against AKI, which is characterized by marked cell death. However, the relationship between PHD inhibition/HIF signaling and ferroptosis in AKI has not been elucidated. Here, we review recent studies to explore the issue. First, we will review the literature concerning the functions of HIF in promoting mitophagy, suppressing mitochondrial respiration and modulating redox homeostasis. Second, we will describe the current understanding of ferroptosis and its role in AKI, particularly from the perspective of mitochondrial dysfunction. Finally, we will discuss the possibility that mitochondria link PHD inhibition/HIF signaling and ferroptosis in AKI. In conclusion, we propose that HIF may protect renal cells against ferroptosis in AKI by reducing mitochondrial oxidative stress and damage.Subject terms: Cell biology, Kidney diseases     

Phosphoinositide 3-kinase is activated by MUC1 but not responsible for MUC1-induced suppression of Toll-like receptor 5 signaling

MUC1 is a membrane-tethered mucin-like glycoprotein expressed on the surface of various mucosal epithelial cells as well as hematopoietic cells. Recently, we showed that MUC1 suppresses flagellin-induced Toll-like receptor (TLR) 5 signaling both in vivo and in vitro through cross talk with TLR5. In this study, we determined whether phosphoinositide 3-kinase (PI3K), a negative regulator of TLR5 signaling, is involved in the cross talk between MUC1 and TLR5 using various genetically modified epithelial cell lines. Our results showed 1) activation of MUC1 induced recruitment of the PI3K regulatory subunit p85 to the MUC1 cytoplasmic tail (CT) as well as Akt phosphorylation, 2) MUC1-induced Akt phosphorylation required the presence of Tyr(20) within the PI3K binding motif of the MUC1 CT, and 3) mutation of Tyr(20) or pharmacological inhibition of PI3K activation failed to block MUC1-induced suppression of TLR5 signaling. We conclude that whereas PI3K is downstream of MUC1 activation and negatively regulates TLR5 signaling, it is not responsible for MUC1-induced suppression of TLR5 signaling.     

山茶属植物ITS的多态性——一个广泛逃离一致性进化的实例

利用位于45S rDNA内转录间隔区（ITS）的3对SSR引物, 对山茶属（Camellia L.）的40个物种进行PCR扩增, 检测3个SSR位点的多态性, 研究物种倍性与多态性之间的关系。实验结果显示, 37个种（占92.5%）的ITS片段存在个体内长度多态性, 在这些种类的个体内至少有2–6类ITS拷贝, 表明山茶属植物的ITS片段存在广泛的非一致性进化; ITS序列上存在易于滑动的SSR位点, 并且其基因组中有较多位于不同染色体上的rDNA位点, 这很可能是山茶属植物ITS片段存在广泛多态性的原因。然而, 研究中没有发现多倍体种类ITS片段的多态性显著高于二倍体种类。山茶属植物ITS片段的多态性提示该属植物的rDNA可能存在更为复杂的进化模式, 在利用ITS片段解决该属植物的系统分类问题时应更为谨慎。     

Depletion of activated hepatic stellate cell correlates with severe liver damage and abnormal liver regeneration in acetaminophen-induced liver injury

Hepatic stellate cells (HSCs) are important part of the local 'stem cell niche' for hepatic progenitor cells (HPCs) and hepatocytes. However, it is unclear as to whether the products of activated HSCs are required to attenuate hepatocyte injury, enhance liver regeneration, or both. In this study, we performed 'loss of function' studies by depleting activated HSCs with gliotoxin. It was demonstrated that a significantly severe liver damage and declined survival rate were correlated with depletion of activated HSCs. Furthermore, diminishing HSC activation resulted in a 3-fold increase in hepatocyte apoptosis and a 66% decrease in the number of proliferating hepatocytes. This was accompanied by a dramatic decrease in the expression levels of five genes known to be up-regulated during hepatocyte replication. In particular, it was found that depletion of activated HSCs inhibited oval cell reaction that was confirmed by decreased numbers of Pank-positive cells around the portal tracts and lowered gene expression level of cytokeratin 19 (CK19) in gliotoxin-treated liver. These data provide clear evidence that the activated HSCs are involved in both hepatocyte death and proliferation of hepatocytes and HPCs in acetaminophen (APAP)-induced acute liver injury.     

Spatial heterogeneity of DTPA-extractable zinc in cultivated soils induced by city pollution and land use

The spatial heterogeneity of DTPA-extractable zinc in the cultivated soils of Shenyang suburbs in Liaoning Province of China was investigated, and its map was drawn by the methods of geostatistics combined with geographic information system. The data of soil DTPA-extractable zinc fitted normal distribution after logarithm transformation, and its semivariogram fitted a spherical model. The semivariogram indicated that the spatial dependence of soil DTPA-extractable zinc content was moderate, with the spatial dependence range of 1.69 km and the fractal dimension of 1.96. Stochastic factors contributed to 49.9% of the spatial variability, while structural factors contributed to 50.1% of it. The spatial heterogeneity of soil DTPA-extractable zinc shown by a kriged interpolation map was deeply influenced by stochastic factors such as city pollution, land use pattern and crop distributions. For example, the average content of Zn in vegetable garden soils was 2.5–4 times as much as in their originated soils, and was lower in paddy soils than in their originated soils. The areas with a higher content of soil DTPA-extractable zinc appeared in the near suburbs and the riverside along Hunhe River and the wastewater drainage of Xihe River, and the extremely high values in the near suburb of the city’s residential area were a striking feature, indicating the key role of city pollution in the spatial heterogeneity of soil DTPA-extractable zinc. When recorded in the form of a soil pollution map, the results of such a survey make it possible to identify the unusually polluted areas, and to provide more information for precise agriculture and environmental control.     

A sustainability analysis of a municipal sewage treatment ecosystem based on emergy

“Discharge of treated wastewater and sewage sludge landfilling” are the most common practice, which poses threats to the local environment. In this work we first constructed a general sewage treatment ecosystem (STE) which integrated the three systems. Emergy synthesis, with several improved emergy-based indicators which considered the waste input contribution and impacts of emissions, was applied to evaluate two alternative scenarios (scenario 1: sewage treatment system + treated water discharge + sludge landfilling; scenario 2: sewage treatment subsystem + reclaimed water reuse subsystem + aerobic compost production subsystem) for Mingjingtan sewage treatment plant in Wanzhou City of Chongqing in China. Results point out the environmental pressure of scenario 2 is much smaller than scenario 1 although its economic performance is somewhat poorer than scenario 1, and finally the sustainability of scenario 2 is still much better than scenario 1. Therefore, the treated water and sewage sludge reuse can further improve the environmental benefit of the sewage treatment process; however, the STE should be optimized in order to enhance its economic benefit. The proposed methods can help policy-makers make decisions and guide designers and operators to improve the comprehensive performance of sewage treatment processes. In addition, this paper also briefly discusses wastewater integrated management strategy.