拟南芥根原生韧皮部筛管分子的超微结构

运用高压冷冻替代方法固定处理材料,在透射电镜下观察了拟南芥（Arabidopsis thaliana L.)根原生韧皮部筛管分子在发育过程中的超微结构变化。结果表明：在筛管分子发育过程中,细胞核具有细胞程序死亡的典型特征,出现核膜内陷、核质聚集并边缘化,核膜破毁以及最后核消失,核膜在破毁前一直呈饱满状态,未出现核膜皱缩,核裂瓣和核周腔明显膨大等现象。在成熟筛管分子的细胞质内,具单层膜的淀粉状颗粒,这些淀粉状态颗粒常与线粒体在一起,可能为线粒体的产能活动提供基质,小液泡发生于内质网,未见大液泡的形成。     

Epithelium segmentation and automated Gleason grading of prostate cancer via deep learning in label‐free multiphoton microscopic images

In the current clinical care practice, Gleason grading system is one of the most powerful prognostic predictors for prostate cancer (PCa). The grading system is based on the architectural pattern of cancerous epithelium in histological images. However, the standard procedure of histological examination often involves complicated tissue fixation and staining, which are time‐consuming and may delay the diagnosis and surgery. In this study, label‐free multiphoton microscopy (MPM) was used to acquire subcellular‐resolution images of unstained prostate tissues. Then, a deep learning architecture (U‐net) was introduced for epithelium segmentation of prostate tissues in MPM images. The obtained segmentation results were then merged with the original MPM images to train a classification network (AlexNet) for automated Gleason grading. The developed method achieved an overall pixel accuracy of 92.3% with a mean F1 score of 0.839 for epithelium segmentation. By merging the segmentation results with the MPM images, the accuracy of Gleason grading was improved from 72.42% to 81.13% in hold‐out test set. Our results suggest that MPM in combination with deep learning holds the potential to be used as a fast and powerful clinical tool for PCa diagnosis.     

Selecting cost effective and policy-relevant biological indicators for European monitoring of soil biodiversity and ecosystem function

Soils provide many ecosystem services that are ultimately dependent on the local diversity and belowground abundance of organisms. Soil biodiversity is affected negatively by many threats and there is a perceived policy requirement for the effective biological monitoring of soils at the European level. The aim of this study was to evaluate and recommend policy relevant, cost-effective soil biological indicators for biodiversity and ecosystem function across Europe. A total of 18 potential indicators were selected using a logical-sieve based approach. This paper considers the use of indicators from the ‘top down’ (i.e. concerned with the process of indicator selection), rather than from the ‘bottom up’ detail of how individual indicators perform at specific sites and with specific treatments. The indicators assessed a range of microbial, faunal and functional attributes, newer nucleic acids based techniques, morphological approaches and process based measurements. They were tested at 6 European experimental sites already in operation and chosen according to land-use, climatic zone and differences in land management intensity. These were 4 arable sites, one each in Atlantic, Continental, Mediterranean and Pannonian climate zones, and 2 grassland sites, one each in Atlantic and Continental zones. At each site we sampled three replicated plots of contrasting management intensity and, while the treatments varied from site to site, their disturbance effects were quantified in terms of land use intensity. The field sampling and laboratory analysis were standardised through a combination of ISO protocols, or standard operating procedures if the former were not available. Sites were sampled twice, in autumn 2012 and spring or autumn 2013, with relative costs of the different indicators being determined each time. A breakdown of the cost effectiveness of the indicators showed the expected trade-off between effort required in the field and effort required in the laboratory. All the indicators were able to differentiate between the sites but, as no single indicator was sensitive to all the differences in land use intensity, we suggest that an indicator programme should be based upon a suite of different indicators. For monitoring under the European climatic zones and land uses of this study, indicators for ecosystem functions related to the services of water regulation, C-sequestration and nutrient provision would include a minimum suite of: earthworms; functional genes; and bait lamina. For effective monitoring of biodiversity all taxonomic groups would need to be addressed.     

远端血管通路导管治疗急性脑梗死对血清Adropin蛋白、载脂蛋白A1的影响

摘要 目的：探讨远端血管通路导管治疗急性脑梗死对血清Adropin蛋白、载脂蛋白A1（ApoA1）的影响。方法：将2018年6月到2021年4月选择在本院急诊的急性脑梗死患者84例作为研究对象,根据随机信封1:1抽签原则把患者分为导管组与支架组,各42例。支架组给予支架溶栓治疗,导管组给予远端血管通路导管治疗,比较两组手术相关指标、mTICI分级情况、脑血液流变学变化以及血清Adropin、ApoA1含量等指标。结果：导管组的导引导管到位时间、血管获得再通时间均较支架组少（P<0.05）;导管组治疗后1个月的血管灌注改良脑梗死溶栓试验（mTICI）分级优于支架组（P<0.05）;两组颅脑椎动脉与基底动脉血流速度治疗前均无差异（P>0.05）,治疗后两组的颅脑椎动脉与基底动脉血流速度高于治疗前（P<0.05）,导管组较支架组高（P<0.05）;两组血清Adropin、ApoA1含量治疗前对比无差异（P>0.05）,治疗后两组的血清Adropin、ApoA1含量较治疗前高（P<0.05）,导管组较支架组高（P<0.05）。结论：远端血管通路导管治疗急性脑梗死可加快手术操作改善患者的血管灌注分级情况,促进血清Adropin、ApoA1的释放,有利于患者脑动脉血流速度的恢复。     

两种钝化剂对污染土壤上生菜吸收重金属和养分的影响

为明确分子筛、硅灰石作为钝化剂修复粤北Cd污染农田土壤的效果,采用盆栽生菜(Lactuca sativa)试验,评估钝化剂应用潜力和对作物营养元素吸收可能的负面效应。结果表明,高剂量(≥660 mg Si/kg)分子筛和硅灰石分别降低了土壤Cd和Pb的有效性,而低剂量(220 mg Si/kg)反而使土壤Cd和Pb有效性上升,添加≥660 mg Si/kg的钝化剂使生菜对Cd和Pb积累具有显著抑制效应。硅灰石通过显著提高土壤有效Ca,增强Ca-Cd竞争吸收来抑制生菜Cd累积,而非通过降低土壤Cd有效性起作用。施用分子筛会降低生菜的Ca、Mg、Mn和Zn含量,小幅增加Cu含量。施用硅灰石则降低生菜的Mn、Zn含量,小幅增加Ca、Cu含量。高剂量(880 mg Si/kg)的分子筛会使生菜产量降低29%,而添加≥660 mg Si/kg硅灰石可使产量提高10%～12%。因此,硅灰石具增产抑Cd效能,在大面积Cd污染土壤的修复中有应用前景,但需适度补充Zn、Mn养分。     

Meiobenthos provides a food resource for young cyprinids

Young individuals of the bottom-biting (i.e. sediment-ingesting) common carp Cyprinus carpio and gudgeon Gobio gobio consumed significant amounts of nematodes in laboratory experiments, whereas the selective-feeding roach Rutilus rutilus did not. In mesocosm enclosure experiments in the field, C. carpio strongly decreased the nematode abundance within 4 days, whereas the bottom-biting bream Abramis brama did not affect the abundance until after 14 days. In controlled experiments with a known number of prey, C. carpio but not A. brama significantly reduced the number of nematodes, and G. gobio reduced the nematode abundance dependent on the size of the fish, with smaller fish causing a greater reduction. Cyprinus carpio consumed the nematodes and did not just mechanically kill them in the sediment, as shown by dissection of the fish intestine. Morphometric analysis of the branchial baskets indicated that the mesh width of C. carpio, but not of A. brama, is suitable for consuming meiobenthos. The results indicate that the meiobenthos is a food resource for certain bottom-feeding freshwater fishes.