Integrated Machine Learning and Bioinformatic Analyses Constructed a Novel Stemness-Related Classifier to Predict Prognosis and Immunotherapy Responses for Hepatocellular Carcinoma Patients

Immunotherapy has made great progress in hepatocellular carcinoma (HCC), yet there is still a lack of biomarkers for predicting response to it. Cancer stem cells (CSCs) are the primary cause of the tumorigenesis, metastasis, and multi-drug resistance of HCC. This study aimed to propose a novel CSCs-related cluster of HCC to predict patients'' response to immunotherapy. Based on RNA-seq datasets from The Cancer Genome Atlas (TCGA) and Progenitor Cell Biology Consortium (PCBC), one-class logistic regression (OCLR) algorithm was applied to compute the stemness index (mRNAsi) of HCC patients. Unsupervised consensus clustering was performed to categorize HCC patients into two stemness subtypes which further proved to be a predictor of tumor immune microenvironment (TIME) status, immunogenomic expressions and sensitivity to neoadjuvant therapies. Finally, four machine learning algorithms (LASSO, RF, SVM-RFE and XGboost) were applied to distinguish different stemness subtypes. Thus, a five-hub-gene based classifier was constructed in TCGA and ICGC HCC datasets to predict patients'' stemness subtype in a more convenient and applicable way, and this novel stemness-based classification system could facilitate the prognostic prediction and guide clinical strategies of immunotherapy and targeted therapy in HCC.     

水稻土中铁氧化物对产甲烷古菌群落结构的影响

产甲烷菌广泛分布在淹水水稻土等各种厌氧环境中,在全球气候变化、碳循环和能源等领域都发挥着重要的作用。研究发现,厌氧条件下,水稻土中铁氧化物的生物还原会抑制产甲烷菌的甲烷合成作用。然而,目前关于铁氧化物对产甲烷菌群落结构的影响报道较少。通过泥浆厌氧培养实验,向采集的水稻土中添加甲酸盐作为甲烷合成的底物(Control,CK处理),并设置添加水铁矿作为体系中唯一电子受体的处理组(Ferrihydrite,Fh处理)。培养结束后,与CK相比,添加水铁矿显著降低了古菌在总微生物群落中的占比,但对古菌群落的物种多样性和均一度没有显著影响;且两组处理中优势种均为操作分类单元(Operational taxonomic unit,OTU)2056和OTU 911(76%—80%)。这说明碳源相同时,产甲烷菌的群落结构不受铁氧化物的影响。本研究为探索土壤中微生物铁还原与碳循环耦合的分子机制奠定基础。     

Genetic analysis of leaffolder resistance in rice

A double haploid(DH)population,which consists of 120 lines derived from anther culture of a typical indica and japonica hybrid 'CJ06'/'TN1',was used to investigate the genetic basis for rice leaffolder resistance.Using a constructed molecular linkage map,five QTLs for rolled leaves were detected on chromosomes 1,2,3,4,and 8.The positive alleles from CJ06 on chromosomes 3,4,and 8 in-creased the resistance to rice leaffolder,and the alleles from TN1 on chromosomes 1 and 2 also enhanced resistance to leaffolde...     

少数民族医学生医学微生物学实验教学的改革与实践——以酸奶制备为例

医学微生物学实验教学中基本操作是双基训练的重要部分,学生对实验技术的掌握程度决定了实验教学的成败。通过酸奶制备的一系列实验过程,把实验内容由验证性改变为设计性,激发了学生的学习兴趣,动手能力提高,实验教学效果良好。     

西鄂尔多斯高原干旱荒漠灌木群落空间分布格局及其竞争关系分析

对西鄂尔多斯高原干旱荒漠中的四合木(Tetraena mongolica Maxim. )、霸王(Sarcozygium xanthoxylon Bunge)、白刺(Nitraria tangutorum Bobr. )和红砂[Reaumuria songarica (Pall. ) Maxim. ]优势群落(样方面积50 m×50 m)进行调查,并按土壤中根系分布深度(0～30、30～60、60～90和大于90 cm)将4种灌木分为4个灌木组,运用单变量函数g(t)、标记相关函数markcorr(t)和双变量函数g12(t)对4个灌木组内灌木的空间分布格局及竞争关系进行了研究.g(t)函数和markcorr(t)函数分析结果显示,4个灌木组内的灌木在0～25 m尺度上几乎都呈显著的随机分布,只有根系分布深度在地下0～30 cm的灌木在小于1 m的尺度上呈现均匀分布;除根系分布深度大于90 cm的灌木的标记在12～13 m尺度上呈现较显著的负相关关系外,在0～25 m尺度上每个灌木组间的标记都不相关,表明根系分布深度相似的灌木间无显著的排斥关系,灌木个体的大小不受周围灌木的影响.g12(t)函数分析结果显示,除根系分布深度为0～30与30～60 cm、30～60与60～90 cm的灌木组间分别在某一中小尺度上(3.0～3.5 m、小于1.5 m和7.0～7.5 m)呈现显著的正相关关系外,在0～25 m尺度内根系分布深度相邻的各灌木组间几乎无显著的相关关系,表明根系分布深度不同的灌木间并不互相影响.研究结果表明,在西鄂尔多斯高原干旱荒漠灌木群落中,具有不同生态学特性的灌木分别占据各自的土壤层,呈现出对土壤水分和养分的分层利用,不存在对资源的竞争.     

植物挥发性信号物质介导抗性的生态功能

植物产生的挥发性化合物能够作为媒介参与植物与周围环境之间的信息交流及相互作用。植物挥发性物质在吸引传粉者、促进种子传播、抑制其它植物种子萌发等方面具有重要的作用。近年来,关于植物挥发性物质在生态系统中的信号作用研究已经成为国内外的研究热点,受到广泛关注。总结了植物挥发性物质作为信号物质在提高植物抗性方面的国内外研究成果,阐述了植物挥发性物质不仅能够直接提高植物的抗性,而且可以作为信号物质在同株、同种异株和不同种植物之间进行传递,进而间接提高目标植物的抗性。最后,还对植物挥发性物质的研究方法和潜在的生态功能进行了探讨。     

新生儿首次呼吸前后脐带动静脉血液氧和二氧化碳变化探索呼吸调控机制的初步报告I—血液氧和二氧化碳分压脐带动静脉差值的组间分析*

目的: 胎儿没有实际上的呼吸,新生儿出生后才开始呼吸,我们假设人的第一次呼吸主要是由于低氧而触发。本研究对流经主动脉体外周化学感受器后的脐带动脉血液氧分压（PuaO₂）变化规律和下限进行分析以探讨新生儿自主呼吸产生机制。方法: 选择签署知情同意书的正常分娩产妇数十例,仅14例新生儿在自主呼吸开始前成功完成脐带动脉或静脉置管。分别进行逐搏取血及顺序血气分析,计算血气指标的平均值、最高值和最低值,统计比较脐带动静脉的异同。结果: 在14例新生儿自主呼吸开始前完成采集脐带动脉（Pua）样本9例,脐带静脉（Puv）样本8例。就PO₂而言,所有9例PuaO₂随时间（心跳次数）呈逐渐降低倾向,直至在自主呼吸产生大约8~10次心跳后Pua挛缩、基本上无法取得足够的血样。PuaO₂平均值是（25.94±6.79,18.04~37.51）mmHg,最高值是（29.11±6.46,23.00~45.90）mmHg,最低值是（21.34±5.54,14.00~33.60）mmHg;但PuaCO₂变化趋势和规律则不够稳定,PuaCO₂平均值是（47.26 ±7.71） mmHg。PuvO₂随时间（心跳次数）虽也呈逐渐降低趋势,但多数还呈现随母亲呼吸节律的规律性交替升降的倾向,特别是母亲吸氧时。所有8例PuvO₂平均值是（53.35±21.35,32.56~100.73）mmHg,最高值是（90.38±48.44,43.40~153.00）mmHg,最低值是（36.96±14.90,24.80~73.80）mmHg;PuvCO₂平均值是（41.04±6.44)mmHg。虽然有着较大的个体差异,但 PuvO₂平均值、最高值和最低值均显著较PuaO₂高（P<0.05）;PuvCO₂虽略低于PuaCO₂,但无显著差异（P>0.05）。结论: 胎儿娩出为新生儿后自主呼吸前PuaO₂随时间（心跳次数）逐渐降低,在达到触发呼吸的阈值时诱发第一次吸气,从而开始自主呼吸。     

Rhodnius prolixus and Rhodnius robustus–like (Hemiptera, Reduviidae) wing asymmetry under controlled conditions of population density and feeding frequency

Habitat change in Rhodnius spp may represent an environmental challenge for the development of the species, particularly when feeding frequency and population density vary in nature. To estimate the effect of these variables in stability on development, the degree of directional asymmetry (DA) and fluctuating asymmetry (FA) in the wing size and shape of R. prolixus and R. robustus–like were measured under laboratory controlled conditions. DA and FA in wing size and shape were significant in both species, but their variation patterns showed both inter-specific and sexual dimorphic differences in FA of wing size and shape induced by nutrition stress. These results suggest different abilities of the genotypes and sexes of two sylvatic and domestic genotypes of Rhodnius to buffer these stress conditions. However, both species showed non-significant differences in the levels of FA between treatments that simulated sylvan vs domestic conditions, indicating that the developmental noise did not explain the variation in wing size and shape found in previous studies. Thus, this result confirm that the variation in wing size and shape in response to treatments constitute a plastic response of these genotypes to population density and feeding frequency.