Cell Surface Beta 1, 4-galactosyltransferase 1 promotes apoptosis by inhibiting epidermal growth factor receptor pathway

Our previous studies have shown that overexpression of β1,4-galactosyltransferase1 (β1,4GT1) leads to increased apoptosis induced by cycloheximide (CHX) in SMMC-7721 human hepatocarcinoma cells. However, the role of β1,4GT1 in apoptosis remains unclear. Here we demonstrated that cell surface β1,4GT1 inhibited the autophosphorylation of epidermal growth factor receptor (EGFR) especially at Try 1068. The phosphorylation of protein kinase B (PKB/Akt) and extracellular signal-regulated protein kinase1/2 (ERK1/2), which are downstream molecules of EGFR, were also reduced in cell surface β1,4GT1-overexpressing cells. Furthermore, the translocations of Bad and Bax that are regulated by PKB/Akt and ERK1/2 were also increased in these cells. As a result, the release of cytochrome c from mitochondria to cytosol was increased and caspase-3 was activated. In contrast, RNAi-mediated knockdown of β1,4GT1 increased the autophosphorylation of EGFR. These results demonstrated that cell surface β1,4GT1 may negatively regulate cell survival possibly through inhibiting and modulating EGFR signaling pathway.     

Heterogeneous impact of cytomegalovirus reactivation on nonrelapse mortality in hematopoietic stem cell transplantation

This study aims to retrospectively analyze the efficacy of penciclovir in the prevention of viral infection after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Ninety-six patients with allo-HSCT were enrolled, who were treated at the Medical Center of Hematology of Xinqiao Hospital from June 2020 to September 2021. The experimental and control groups were treated with penciclovir and acyclovir, respectively, to prevent viral infection. By February 2022, the infection rates of cytomegalovirus, BK virus, JC virus, and Epstein-Barr virus (EBV) in the experimental group and the control group were 18.8% and 39.06% (P<0.05), 28.1% and 25% (P>0.05), 6.2% and 7.81% (P>0.05), 21.8% and 23.43% (P>0.05), respectively. The infection-related urinary system symptoms of the experimental group and the control group occurred in 4 and 9 patients, respectively, of which 3 and 9 patients died, respectively. Penciclovir can significantly reduce the cytomegalovirus infection rate after allo-HSCT and has better preventive effects than acyclovir without obvious side effects. The effectiveness and safety of penciclovir will be further verified in the future.     

A secreted ribonuclease effector from Verticillium dahliae localizes in the plant nucleus to modulate host immunity

The arms race between fungal pathogens and plant hosts involves recognition of fungal effectors to induce host immunity. Although various fungal effectors have been identified, the effector functions of ribonucleases are largely unknown. Herein, we identified a ribonuclease secreted by Verticillium dahliae (VdRTX1) that translocates into the plant nucleus to modulate immunity. The activity of VdRTX1 causes hypersensitive response (HR)‐related cell death in Nicotiana benthamiana and cotton. VdRTX1 possesses a signal peptide but is unlikely to be an apoplastic effector because its nuclear localization in the plant is necessary for cell death induction. Knockout of VdRTX1 significantly enhanced V. dahliae virulence on tobacco while V. dahliae employs the known suppressor VdCBM1 to escape the immunity induced by VdRTX1. VdRTX1 homologs are widely distributed in fungi but transient expression of 24 homologs from other fungi did not yield cell death induction, suggesting that this function is specific to the VdRTX1 in V. dahliae. Expression of site‐directed mutants of VdRTX1 in N. benthamiana leaves revealed conserved ligand‐binding sites that are important for VdRTX1 function in inducing cell death. Thus, VdRTX1 functions as a unique HR‐inducing effector in V. dahliae that contributes to the activation of plant immunity.     

The structural dynamics of full-length divisome transmembrane proteins FtsQ,FtsB, and FtsL in FtsQBL complex formation

FtsQBL is a transmembrane protein complex in the divisome of Escherichia coli that plays a critical role in regulating cell division. Although extensive efforts have been made to investigate the interactions between the three involved proteins, FtsQ, FtsB, and FtsL, the detailed interaction mechanism is still poorly understood. In this study, we used hydrogen-deuterium exchange mass spectrometry to investigate these full-length proteins and their complexes. We also dissected the structural dynamic changes and the related binding interfaces within the complexes. Our data revealed that FtsB and FtsL interact at both the periplasmic and transmembrane regions to form a stable complex. Furthermore, the periplasmic region of FtsB underwent significant conformational changes. With the help of computational modeling, our results suggest that FtsBL complexation may bring the respective constriction control domains (CCDs) in close proximity. We show that when FtsBL adopts a coiled-coil structure, the CCDs are fixed at a vertical position relative to the membrane surface; thus, this conformational change may be essential for FtsBL’s interaction with other divisome proteins. In the FtsQBL complex, intriguingly, we show only FtsB interacts with FtsQ at its C-terminal region, which stiffens a large area of the β-domain of FtsQ. Consistent with this, we found the connection between the α- and β-domains in FtsQ is also strengthened in the complex. Overall, the present study provides important experimental evidence detailing the local interactions between the full-length FtsB, FtsL, and FtsQ protein, as well as valuable insights into the roles of FtsQBL complexation in regulating divisome activity.     

Aldolase A Enhances Intrahepatic Cholangiocarcinoma Proliferation and Invasion through Promoting Glycolysis

Energy metabolism reprogramming has been implicated in tumorigenesis and development. Key metabolism enzyme Aldolase A (ALDOA) has been shown to be highly expressed and involved in various kinds of cancers including hepatocellular carcinoma. In this study, we found that ALDOA was highly expressed in clinical intrahepatic cholangiocarcinoma (ICC) tissues, and its high expression was negatively correlated with overall survival (OS) and recurrence-free survival (RFS) in ICC patients. Knockdown of ALDOA expression significantly inhibited the proliferation and migration of ICC both in vitro and in vivo, while highly-expressed ALDOA in ICC cells promoted the proliferation and migration of ICC cells. By applying ALDOA inhibitor and metabolic mass spectrometry tests, we demonstrated that ALDOA modulated the biological characteristics and metabolic level of ICC cells depending on its enzymatic activity. In summary, ALDOA promotes ICC proliferation and migration by enhancing ICC cells glycolysis. Blocking enzymatic activity of ALDOA provides a strategy to inhibit ICC.     

蓝藻伪空胞的特性及浮力调节机制

伪空胞为蓝藻在水体中提供浮力,使其获得适宜的生长条件,最终导致蓝藻水华暴发,了解伪空胞的特征对控制蓝藻水华暴发有重要意义。文章简要回顾了蓝藻伪空胞自1865年被Klebahn发现到1965年被正式命名的研究历程,目前已发现150多种原核生物中含有伪空胞;伪空胞是两末端呈圆锥状的中空圆柱体,伪空胞半径与临界压强遵循方程:Pc=275(r/nm)-1.67MPa;伪空胞气体含量可根据不同原理,利用Walsby伪空胞测定装置、压力浊度计和细胞流式仪测得。总结了伪空胞组成的化学特性,评述了伪空胞gvp基因丛结构功能和GvpA、GvpC的蛋白空间结构。GvpA是伪空胞合成的主要成分,gvpA在伪空胞内存在多个拷贝,其功能仍不清楚;GvpC由33个氨基酸重复单位组成,重复单位越多,伪空胞越不易破裂;概述了伪空胞3种浮力调节机制:镇重物的改变、伪空胞的合成、伪空胞的破裂;归纳了环境因子(光照、温度、氮、磷、钾)参与伪空胞浮力网络调控的途径。提出了目前伪空胞研究面临的困难和问题,对伪空胞的未来研究方向提出探索性的建议。     

Varietal effects of eight paired lines of transgenic Bt maize and near-isogenic non-Bt maize on soil microbial and nematode community structure

A glasshouse experiment was undertaken to provide baseline data on the variation between conventional maize (Zea mays L.) varieties and genetically modified maize plants expressing the insecticidal Bacillus thuringiensis protein (Bt, Cry1Ab). The objective was to determine whether the variation in soil parameters under a range of conventional maize cultivars exceeded the differences between Bt and non-Bt maize cultivars. Variations in plant growth parameters (shoot and root biomass, percentage carbon, percentage nitrogen), Bt protein concentration in shoots, roots and soil, soil nematode abundance and soil microbial community structure were determined. Eight paired varieties (i.e. varieties genetically modified to express Bt protein and their near-isogenic control varieties) were investigated, together with a Bt variety for which no near-isogenic control was available (NX3622, a combined transformant expressing both Bt and herbicide tolerance) and a conventional barley (Hordeum vulgare L.) variety which was included as a positive control. The only plant parameter which showed a difference between Bt varieties and near-isogenic counterparts was the shoot carbon to nitrogen ratio; this was observed for only two of the eight varieties, and so was not attributable to the Bt trait. There were no detectable differences in the concentration of Bt protein in plant or soil with any of the Bt-expressing varieties. There were significant differences in the abundance of soil nematodes, but this was not related to the Bt trait. Differences in previously published soil nematode studies under Bt maize were smaller than these varietal effects. Soil microbial community structure, as determined by phospholipid fatty acid (PLFA) analysis, was strongly affected by plant growth stage but not by the Bt trait. The experimental addition of purified Cry1Ab protein to soil confirmed that, at ecologically relevant concentrations, there were no measurable effects on microbial community structure.     

乳链球菌SB900胞壁肽聚糖的部分生物学活性

对乳链球菌（Streptococcuslactis）SB900胞壁肽聚糖（简称为LABPG）进行了分离纯化及化学成分分析,并测定了其部分生物学活性．结果表明,LABPG蛋白质含量为9．84％,NAG0．871μmol／mg,NAM1．14μmol／mg;氨基酸分析结果表明,Ala、Glu、Asp含量较高,分别为1．046、0．775、0．304μmol／mg。以小鼠为实验材料进行动物学实验,对LABPG的生物学活性测定结果表明,LANPG无毒、安全可靠;腹腔注射LABPG后,PMΦ数目增多,吞噬功能明显增强,血清溶菌酶活性增强;YC-花环实验表明,腹腔注射LABPG的小鼠PMΦ表面C3b受体活性增强,YC-花环形成率较高,统计学分析有显著差别。说明LABPG对于MΦ有一定的激活作用,可作为机体的免疫激活剂。