Some observations on the localization of mitomycin C-induced aberrations in human lymphocytes

Actively cycling human lymphocytes were treated with mitomycin C for 1 h (1.4 μg/ml) and then grown in medium containing 10 μg/ml bromodeoxyuridine. Serial 5-h colcemid accumulation samples were taken up to 35 h and the air-dried methaphase spreads stained for replication banding. A complete cell-cycle subphasing analysis was made, and classified cells scored for all categories of chromatid-type aberrations and their location.

Inspite of the high dose which produced massive delay and cycle perturbation, there was no evidence for selectively lethality of early-S cells, in fact such cells were in excess. Extreme localization of aberrations to late-replicating (mostly centromeric) regions was found at all subphases and in pre-S cells. This rules out ‘localization by default’ as an explanation for the observed preferential occurence of ‘break points’ in these regions.

The frequency of incomplete intrachanges, low in late S, rises dramaticallyin early S to become maximal in pre-S cells.     

Rational Design of Nanocatalysts with Nonmetal Species Modification for Electrochemical CO2 Reduction

Converting CO₂ to valuable carbonaceous fuels and chemicals via electrochemical CO₂ reduction by using renewable energy sources is considered to be a scalable strategy with substantial environmental and economic benefits. One of the challenges in this field is to develop nanocatalysts with superior electrocatalytic activity and selectivity for targeted products. Nonmetal species modification of nanocatalysts is of great significance for the construction of distinctive active sites to overcome the kinetic limitations of CO₂ reduction. These types of modification enable the efficient control of the selectivity and significantly decrease the reaction overpotential. Herein, a comprehensive review of the recent progress of nonmetal species modification of nanocatalysts for electrochemical CO₂ reduction is presented. After discussing some fundamental parameters and the basic principles of CO₂ reduction, including possible reaction pathways in light of theoretical modeling and experiments, the identification of active sites and elucidation of reaction mechanisms are emphasized for unraveling the role of nonmetal species modification, such as heteroatom incorporation, organic molecule decoration, electrolyte engineering, and single‐atom engineering. In the final section, future challenges and constructive perspectives are provided, facilitating the accelerated advancement of mechanism research and practical applications of green carbon cycling.     

Ultra‐high α‐linolenic acid accumulating developmental defective embryo was rescued by lysophosphatidic acid acyltransferase 2

For decades, genetic engineering approaches to produce unusual fatty acids (UFAs) in crops has reached a bottleneck, including reduced seed oil production and seed vigor. Currently, plant models in the field of research are primarily used to investigate defects in oil production and seedling development, while the role of UFAs in embryonic developmental defects remains unknown. In this study, we developed a transgenic Arabidopsis plant model, in which the embryo exhibits severely wrinkled appearance owing to α‐linolenic acid (ALA) accumulation. RNA‐sequencing analysis in the defective embryo suggested that brassinosteroid synthesis, FA synthesis and photosynthesis were inhibited, while FA degradation, endoplasmic reticulum stress and oxidative stress were activated. Lipidomics analysis showed that ultra‐accumulated ALA is released from phosphatidylcholine as a free FA in cells, inducing severe endoplasmic reticulum and oxidative stress. Furthermore, we identified that overexpression of lysophosphatidic acid acyltransferase 2 rescued the defective phenotype. In the rescue line, the pool capacity of the Kennedy pathway was increased, and the esterification of ALA indirectly to triacylglycerol was enhanced to avoid stress. This study provides a plant model that aids in understanding the molecular mechanism of embryonic developmental defects and generates strategies to produce higher levels of UFAs.     

Human bone marrow mesenchymal stem cell-derived extracellular vesicles impede the progression of cervical cancer via the miR-144-3p/CEP55 pathway

Cervical cancer is the most common gynaecological malignancy, with a high incidence rate and mortality rate in middle-aged women. Human bone marrow mesenchymal stem cells (hBMSCs) have been implicated in the initiation and subsequent development of cancer, along with the involvement of extracellular vesicles (EVs) mediating intracellular communication by delivering microRNAs (miRNAs or miRs). This study is aimed at investigating the physiological mechanisms by which EVs-encapsulated miR-144-3p derived from hBMSCs might mediate the progression of cervical cancer. The expression profiles of centrosomal protein, 55 Kd (CEP55) and miR-144-3p in cervical cancer cell lines and tissues, were quantified by RT-qPCR and Western blot analysis. The binding affinity between miR-144-3p and CEP55 was identified using in silico analysis and luciferase activity determination. Cervical cancer cells were co-cultured with EVs derived from hBMSCs that were treated with either miR-144-3p mimic or miR-144-3p inhibitor. Cervical cancer cell proliferation, invasion, migration and apoptosis were detected in vitro. The effects of hBMSCs-miR-144-3p on tumour growth were also investigated in vivo. miR-144-3p was down-regulated, whereas CEP55 was up-regulated in cervical cancer cell lines and tissues. CEP55 was targeted by miR-144-3p, which suppressed cervical cancer cell proliferation, invasion and migration and promoted apoptosis via CEP55. Furthermore, similar results were obtained by hBMSCs-derived EVs carrying miR-144-3p. In vivo assays confirmed the tumour-suppressive effects of miR-144-3p in hBMSCs-derived EVs on cervical cancer. Collectively, hBMSCs-derived EVs-loaded miR-144-3p impedes the development and progression of cervical cancer through target inhibition of CEP55, therefore providing us with a potential therapeutic target for treating cervical cancer.     

Circular RNAs acting as ceRNAs mediated by miRNAs may be involved in the synthesis of soybean fatty acids

Functional & Integrative Genomics - Soybean oil is composed of fatty acids and glycerol. The content and composition of fatty acids partly determine the quality of soybean seeds. Circular RNAs...     

吉林省辽源地区羊肚菌根际土壤真菌多样性及群落组成

为探究羊肚菌Morchella与不同土壤生长环境及土壤理化因子的关系,以吉林省辽源市的野生和栽培两种生境为样地,采集羊肚菌根际土壤样品为材料,通过Illumina MiSeq高通量测序技术,对羊肚菌土壤真菌群落结构和多样性进行研究,同时分析土壤理化因子对其真菌群落多样性及优势菌属的影响。通过Alpha多样性分析发现:与对照组相比,不论是野生环境还是栽培环境,羊肚菌生长之后的土壤真菌的群落组成多样性降低;通过Beta多样性分析发现:两组根际土壤真菌组成差异非常明显,说明不同的羊肚菌生长环境对土壤真菌组成有重要影响,同时,野生羊肚菌根际土壤真菌优势菌属是被孢霉属Mortierella,栽培羊肚菌根际土壤真菌优势菌属是红菇属Russula。土壤冗余分析表明土壤理化指标中全氮(TN)、有机碳(OC)对土壤真菌群落多样性影响最大,野生羊肚菌根际土壤中的优势菌属被孢霉属与TN、OC 2种元素呈正相关,而栽培羊肚菌根际土壤中的优势菌属红菇属与Mg~(2+)、全磷(TP)、Ca~(2+)和K~+4种元素呈正相关。研究结果表明羊肚菌更喜欢生活在略偏碱的土壤环境。     

Prognostic Value of Cancer Stem Cell Marker Aldehyde Dehydrogenase in Ovarian Cancer: A Meta-Analysis

Objective

Aldehyde dehydrogenase (ALDH) has recently been reported as a marker of cancer stem-like cells in ovarian cancer. However, the prognostic role of ALDH in ovarian cancer still remains controversial. In this study, we aimed to evaluate the association between the expression of ALDH and the outcome of ovarian cancer patients by performing a meta-analysis.

Methods

We systematically searched for studies investigating the relationships between ALDH expression and outcome of ovarian cancer patients. Only articles in which ALDH expression was detected by immunohistochemical staining were included. A meta-analysis was performed to generate combined hazard ratios (HRs) with 95% confidence intervals (CIs) for overall survival (OS) and disease-free survival (DFS).

Results

A total of 1,258 patients from 7 studies (6 articles) were included in the analysis. Our results showed that high ALDH expression in patients with ovarian cancer was associated with poor prognosis in terms of Os (HR, 1.25; 95% CI, 1.07-1.47; P = 0.005) and DFS (HR, 1.58; 95% CI, 1.00-2.49; P = 0.052), though the difference for DFS was not statistically significant. In addition, there was no evidence of publication bias as suggested by Begg’s and Egger’s tests (Begg’s test, P = 0.707; Egger’s test, P = 0.355).

Conclusion

The present meta-analysis indicated that elevated ALDH expression was associated with poor prognosis in patients with ovarian cancer.     

Investigation of the binding network of IGF-I on the cavity surface of IGFBP4

Insulin-like growth factor-binding proteins (IGFBPs) control bioactivity and distribution of insulin-like growth factors (IGFs) through high-affinity complex of IGFBP and IGF. To get more insight into the binding interaction of IGF system, the site-directed mutagenesis and force-driving desorption methods were employed to study the interaction mechanism of IGFBP4 and IGF-I by molecular dynamics (MD) simulation. In IGF-I, residues Gly7 to Asp12 were found to be the hot spots and they mainly anchored on the N-domain of IGFBP4. The contact area, the shape and size of protein, the surroundings of the binding site, the hydrophobic and electrostatic interaction between the two proteins worked as a complex network to regulate the protein-protein interaction. It was also found that the unfolding of the helix was not inevitable in the mutant, and it could be regulated by careful selection of the substituted amino acid.

Expression Profiles of Long Noncoding RNAs and Messenger RNAs in Mn-Exposed Hippocampal Neurons of Sprague–Dawley Rats Ascertained by Microarray: Implications for Mn-Induced Neurotoxicity

Manganese (Mn) is an essential trace element, while excessive expose may induce neurotoxicity. Recently, lncRNAs have been extensively studied and it has been confirmed that lncRNAs participate in neural functions and aberrantly expressed lncRNAs are involved in neurological diseases. However, the pathological effects of lncRNAs on Mn-induced neurotoxicity remain unclear. In this study, the expression profiles of lncRNAs and messenger RNAs (mRNAs) were identified in Mn-treated hippocampal neurons and control neurons via microarray. Bioinformatic methods and intersection analysis were also employed. Results indicated that 566, 1161, and 1474 lncRNAs meanwhile 1848, 3228, and 4022 mRNAs were aberrantly expressed in low, intermediate, and high Mn-exposed groups compared with the control group, respectively. Go analysis determined that differentially expressed mRNAs were targeted to biological processes, cellular components, and molecular functions. Pathway analysis indicated that these mRNAs were enriched in insulin secretion, cell cycle, and DNA replication. Intersection analysis denominated that 135 lncRNAs and 373 mRNAs were consistently up-regulated while 150 lncRNAs and 560 mRNAs were consistently down-regulated. Meanwhile, lncRNA {"type":"entrez-nucleotide","attrs":{"text":"BC079195","term_id":"50926238"}}BC079195 was significantly up-regulated while lncRNAs uc.229- and {"type":"entrez-nucleotide","attrs":{"text":"BC089928","term_id":"59808777"}}BC089928 were significantly down-regulated in three comparison groups. The relative expression levels of 3 lncRNAs and 4 mRNAs were validated through qRT-PCR. To the best of our knowledge, this study is the first to identify the expression patterns of lncRNAs and mRNAs in hippocampal neurons of Sprague–Dawley rats. The results may provide evidence on underlying mechanisms of Mn-induced neurotoxicity, and aberrantly expressed lncRNAs/mRNAs may be useful in further investigations to detect early symptoms of Mn-induced neuropsychiatric disorders in the central nervous system.