中国东北地区流动沙丘生态系统丘间低地地下芽库的时空变化

中国东北地区流动沙丘生态系统丘间低地地下芽库的时空变化 地下芽库在半干旱区沙丘生态系统植被恢复中起着重要作用。然而,目前针对流动沙丘丘间低地地下芽库时空变化的研究却很少。本研究通过调查一个生长季内5个不同面积流动沙丘丘间低地地下芽库的大小和组成,确定流动沙丘丘间低地地下芽库的时空变化。研究结果显示,中等面积丘间低地的总芽库密度与分蘖芽密度最高,茎基部芽密度呈相反趋势,而根茎芽密度不随丘间低地的面积变化而变化。地下芽库大小具有明显的季节变化特征。总芽密度在8月份达到高峰,10月份最低,根茎芽密度变化趋势与总芽密度相似,而茎基芽密度变化趋势与总芽密度相反,分蘖芽密度的变化不明显。以上结果表明,地下芽库密度随丘间低地的面积和季节变化而变化。这一结果有助于认识流动沙丘生态系统中植物生长的适应策略,并可为半干旱区沙丘植被恢复和保护提供理论指导。     

Responses of soil labile organic carbon and water-stable aggregates to reforestation in southern subtropical China

中国南亚热带土壤易分解有机碳和水稳性团聚体对造林的响应 造林被认为可以提高土壤碳稳定性并促进土壤碳累积。然而,实验结果差异很大,造林在提高土壤碳稳定性方面的作用仍存在争议。因此,在森林生态系统中不同土壤碳库对造林如何响应目前尚不清楚。基于此,本文对亚热带地区的尾叶桉林(Eucalyptus urophylla)、厚荚相思林(Acacia crassicarpa)、 红锥林(Castanopsis hystrix)、10树种混交林和自然恢复草坡等5种不同林型的土壤碳组分进行了研究,评估其不同土层(0–10、10–20、20–40 和40–60 cm)中的土壤易分解有机碳(容易被高锰酸钾氧化的有机碳ROC和土壤可溶性有机碳DOC)及土壤团聚体相关的碳对造林的响应。实验结果表明,造林(与自然恢复草坡比较)和林型并没有显著影响土壤ROC浓度,而自然恢复草坡土壤的DOC浓度在4个土层中均最高。0–10 cm土层中各径级的土壤团聚体其碳(C)浓度均是红锥林最高。此外,在任一土层中,林型对不同径级土壤水稳性团聚体比例的影响均不显著。但是土壤深度显著改变土壤团聚体的分布,0–20 cm土层主要为>0.25 mm粒径的团聚体,20–60 cm土层则是0.053–2 mm粒径的团聚体占主导。这些结果显示造林和林型影响土壤DOC 和团聚体C,而且它们相比于ROC对造林的响应更为敏感。研究发现,与自然恢复相比,人工林降低了土壤DOC浓度,暗示它可能会减少土壤C的淋溶损失。此外,红锥林能够通过物理保护提高表土层中土壤碳的稳定性。本研究为关注土壤碳汇功能时的中国南亚热带地区造林树种选择提供了有价值的信息。     

An inducible model for specific neutrophil depletion by diphtheria toxin in mice

Science China Life Sciences - Neutrophils are crucial for immunity and play important roles in inflammatory diseases; however, mouse models selectively deficient in neutrophils are limited, and...     

Bi-FoRe:an efficient bidirectional knockin strategy to generate pairwise conditional alleles with fluorescent indicators

Gene expression labeling and conditional manipulation of gene function are important for elaborate dissection of gene function.However,contemporary generation of pairwise dual-function knockin alleles to achieve both conditional and geno-tagging effects with a single donor has not been reported.Here we first developed a strategy based on a flipping donor named FoRe to generate conditional knockout alleles coupled with fluorescent allele-labeling through NHEJ-mediated unidirectional targeted insertion in zebrafish facilitated by the CRISPR/Cas system.We demonstrated the feasibility of this strategy at sox10 and isl1 loci,and successfully achieved Cre-induced conditional knockout of target gene function and simultaneous switch of the fluorescent reporter,allowing generation of genetic mosaics for lineage tracing.We then improved the donor design enabling efficient one-step bidirectional knockin to generate paired positive and negative conditional alleles,both tagged with two different fluorescent reporters.By introducing Cre recombinase,these alleles could be used to achieve both conditional knockout and conditional gene restoration in parallel;furthermore,differential fluorescent labeling of the positive and negative alleles enables simple,early and efficient realtime discrimination of individual live embryos bearing different genotypes prior to the emergence of morphologically visible phenotypes.We named our improved donor as Bi-FoRe and demonstrated its feasibility at the sox10 locus.Furthermore,we eliminated the undesirable bacterial backbone in the donor using minicircle DNA technology.Our system could easily be expanded for other applications or to other organisms,and coupling fluorescent labeling of gene expression and conditional manipulation of gene function will provide unique opportunities to fully reveal the power of emerging single-cell sequencing technologies.     

Re-detectable positive SARS-CoV-2 RNA tests in patients who recovered from COVID-19 with intestinal infection

Dear Editor,Severe acute respiratory syndrome coronavirus 2(SARSCoV-2),a novel coronavirus that causes Coronavirus Disease 2019(COVID-19)(Yang and Wang,2020),has spread to more than 200 countries and infected more than 9,000,000 people as of Jun 2020.Tens of thousands of patients with COVID-19 have recovered and been discharged from hospital.However,there are reports of recovered patients who subsequently tested positive for SARSCoV-2 after discharge(re-detectable positive,RP)(An et al.,2020;Lan et al.,2020),and this has led to increasing focus on the mechanism(s)underlying RP.     

Unexpected guests in the tumor microenvironment:microbiome in cancer

Although intestinal microbiome have been established as an important biomarker and regulator of cancer development and therapeutic response,less is known about the role of microbiome at other body sites in cancer.Emerging evidence has revealed that the local microbiota make up an important part of the tumor microenvironment across many types of cancer,espe-cially in cancers arising from mucosal sites,including the lung,skin and gastrointestinal tract.The populations of bacteria that reside specifically within tumors have been found to be tumor-type specific,and mechanistic studies have demonstrated that tumor-associated microbiota may directly regulate cancer initiation,pro-gression and responses to chemo-or immuno-thera-pies.This review aims to provide a comprehensive review of the important literature on the microbiota in the cancerous tissue,and their function and mechanism of action in cancer development and treatment.     

Structure of intact human MCU supercomplex with the auxiliary MICU subunits

Dear Editor,Mitochondrial Ca2+homeostasis regulates energy production,cell division,and cell death.The basic properties of mitochondrial Ca2+uptake have been firmly established.The Ca2+influx is mediated by MCU,driven by membrane potential and using a uniporter mechanism(Vasington and Murphy,1962).Patch-clamp analysis of MCU currents demonstrated that MCU is a channel with exceptionally high Ca2+selectivity(Kirichok et al.,2004).     

Molecular deconvolution of the neutralizing antibodies induced by an inactivated SARS-CoV-2 virus vaccine

Dear Editor, The rapid emergence and persistence of the pandemic caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) has had enormous impacts on global health and the economy.Effective vaccines against SARS-CoV-2 are urgently needed to control the coronavirus disease 2019(COVID-19) pandemic,and multiple vaccines have been found to be efficacious in preventing symptomatic COVID-19(Polack et al.,2020;Wu et al.,2020;Jones and Roy,2021).We have developed a traditional beta-propiolactone-inacti-vated aluminum hydroxide-adjuvanted whole-virion SARS-CoV-2 vaccine (BBIBP-CorV),which elicited protective immune responses in clinical trials (Wang et al.,2020;Xia et al.,2021).The vaccine has been granted conditional approvals or emergency use authorizations (EUAs) in China and other countries.     

Effects of a Potential Host Gut-Derived Probiotic,Bacillus subtilis 6-3-1, on the Growth,Non-specific Immune Response and Disease Resistance of Hybrid Grouper (Epinephelus fuscoguttatus♀ × Epinephelus lanceolatus♂)

Probiotics and Antimicrobial Proteins - A potential host-derived probiotic, Bacillus subtilis 6-3-1, was successfully screened from 768 isolates from the intestines of healthy hybrid grouper...     

Multifaceted roles of duckweed in aquatic phytoremediation and bioproducts synthesis

Duckweed (Lemnaceae) is a fast‐growing aquatic vascular plant. It has drawn an increasing attention worldwide due to its application in value‐added nutritional products and in sewage disposal. In particular, duckweed is a promising feedstock for bioenergy production. In this review, we summarized applications of duckweed from the following four aspects. Firstly, duckweed could utilize nitrogen, phosphorus, and inorganic nutrition in wastewater and reduces water eutrophication efficiently. During these processes, microorganisms play an important role in promoting duckweed growth and improving its tolerance to stresses. We also introduced our pilot‐scale test using duckweed for wastewater treatment and biomass production simultaneously. Secondly, its capability of fast accumulation of large amounts of starch makes duckweed a promising bioenergy feedstock, catering the currently increasing demand for bioethanol production. Pretreatment conditions prior to fermentation can be optimized to improve the conversion efficiency from starch to bioethanol. Furthermore, duckweed serves as an ideal source for food supply or animal feed because the composition of amino acids in duckweed is similar to that of whey protein, which is easily digested and assimilated by human and other animals. Finally, severing as a natural plant factory, duckweed has shown great potential in the production of pharmaceuticals and dietary supplements. With the surge of omics data and the development of Clustered Regularly Interspaced Short Palindromic Repeats technology, remodeling of the metabolic pathway in duckweed for synthetic biology study will be attainable in the future.