评价植物悬浮细胞培养物两项测定指标的建立

由于在细胞培养研究中缺乏一些可操作性强的且定量化的细胞状态评价指标,人们对植物细胞状态的有些性状的评价只能停留在定性描述水平,如对悬浮细胞培养物褐化程度的评价仅能作出定性判断。这里我们提出了两项悬浮细胞培养物细胞状态评价指标。     

多荚草中的新三萜皂甙

从石竹科植物多荚草（Ｐｏｌｙｃａｒｐｏｎ ｐｒｏｓｔｒａｔｕｍ（Ｆｏｒｓｓｋ．）Ａｓｃｈｅｒｓ．ｅｔ Ｓｃｈｗｅｉｎ．ｅｘ Ａｓｃｈｅｒｓ）中分离得到３个新的柴胡皂甙类化合物：ｐｒｏｓｔｒａｔｏｓｉｄｅ Ａ￣Ｃ（１￣３）。它们的结构通过波谱方法分别鉴定为：３－Ｏ－｛β－Ｄ－ｘｙｌｏｐｙｒａｎｏｓｙｌ－（１→２）－β－Ｄ－ｇｌｕｃｏｐｙｒａｎｏｓｙｌ－（１→４）－「β－Ｄ－ｇｌｕｃｏｐｙｒａｎｏｓｙ     

Altered Anatomical Network in Early Blindness Revealed by Diffusion Tensor Tractography

The topological architecture of the cerebral anatomical network reflects the structural organization of the human brain. Recently, topological measures based on graph theory have provided new approaches for quantifying large-scale anatomical networks. Diffusion MRI studies have revealed the efficient small-world properties and modular structure of the anatomical network in normal subjects. However, no previous study has used diffusion MRI to reveal changes in the brain anatomical network in early blindness. Here, we utilized diffusion tensor imaging to construct binary anatomical networks for 17 early blind subjects and 17 age- and gender-matched sighted controls. We established the existence of structural connections between any pair of the 90 cortical and sub-cortical regions using deterministic tractography. Compared with controls, early blind subjects showed a decreased degree of connectivity, a reduced global efficiency, and an increased characteristic path length in their brain anatomical network, especially in the visual cortex. Moreover, we revealed some regions with motor or somatosensory function have increased connections with other brain regions in the early blind, which suggested experience-dependent compensatory plasticity. This study is the first to show alterations in the topological properties of the anatomical network in early blindness. From the results, we suggest that analyzing the brain''s anatomical network obtained using diffusion MRI data provides new insights into the understanding of the brain''s re-organization in the specific population with early visual deprivation.     

Who Are the High-Cost Users? A Method for Person-Centred Attribution of Health Care Spending

Objective

To develop person-centered episodes of care (PCE) for community-dwelling individuals in the top fifth percentile of Ontario health care expenditures in order to: (1) describe the main clinical groupings for spending; and (2) identify patterns of spending by health sector (e.g. acute care, home care, physician billings) within and across PCE.

Data sources

Data were drawn from population-based administrative databases for all publicly funded health care in Ontario, Canada in 2010/11.

Study design

This study is a retrospective cohort study.

Data collection/extraction methods

A total of 587,982 community-dwelling individuals were identified among those accounting for the top 5% of provincial health care expenditures between April 1, 2010 and March 31, 2011. PCE were defined as starting with an acute care admission and persisting through subsequent care settings and providers until individuals were without health system contact for 30 days. PCE were classified according to the clinical grouping for the initial admission. PCE and non-PCE costs were calculated and compared to provide a comprehensive measurement of total health system costs for the year.

Principal findings

Among this community cohort, 697,059 PCE accounted for nearly 70% ($11,815.3 million (CAD)) of total annual publicly-funded expenditures on high-cost community-dwelling individuals. The most common clinical groupings to start a PCE were Acute Planned Surgical (35.2%), Acute Unplanned Medical (21.0%) and Post-Admission Events (10.8%). Median PCE costs ranged from $3,865 (IQR = $1,712-$10,919) for Acute Planned Surgical to $20,687 ($12,207-$39,579) for Post-Admission Events. Inpatient acute ($8,194.5 million) and inpatient rehabilitation ($434.6 million) health sectors accounted for the largest proportions of allocated PCE spending over the year.

Conclusions

Our study provides a novel methodological approach to categorize high-cost health system users into meaningful person-centered episodes. This approach helps to explain how costs are attributable within individuals across sectors and has applications in episode-based payment formulas and quality monitoring.     

Studies of Antibiotic Resistance of Beta-Lactamase Bacteria under Different Nutrition Limitations at the Single-Cell Level

Drug resistance involves many biological processes, including cell growth, cell communication, and cell cooperation. In the last few decades, bacterial drug resistance studies have made substantial progress. However, a major limitation of the traditional resistance study still exists: most of the studies have concentrated on the average behavior of enormous amounts of cells rather than surveying single cells with different phenotypes or genotypes. Here, we report our study of beta-lactamase bacterial drug resistance in a well-designed microfluidic device, which allows us to conduct more controllable experiments, such as controlling the nutrient concentration, switching the culture media, performing parallel experiments, observing single cells, and acquiring time-lapse images. By using GFP as a beta-lactamase indicator and acquiring time-lapse images at the single-cell level, we observed correlations between the bacterial heterogeneous phenotypes and their behavior in different culture media. The feedback loop between the growth rate and the beta-lactamase production suggests that the beta-lactamase bacteria are more resistant in a rich medium than in a relatively poor medium. In the poorest medium, the proportion of dormant cells may increase, which causes a lower death rate in the same generation. Our work may contribute to assaying the antibiotic resistance of pathogenic bacteria in heterogeneous complex media.     

SNAREs support atlastin-mediated homotypic ER fusion in Saccharomyces cerevisiae

Dynamin-like GTPases of the atlastin family are thought to mediate homotypic endoplasmic reticulum (ER) membrane fusion; however, the underlying mechanism remains largely unclear. Here, we developed a simple and quantitative in vitro assay using isolated yeast microsomes for measuring yeast atlastin Sey1p-dependent ER fusion. Using this assay, we found that the ER SNAREs Sec22p and Sec20p were required for Sey1p-mediated ER fusion. Consistently, ER fusion was significantly reduced by inhibition of Sec18p and Sec17p, which regulate SNARE-mediated membrane fusion. The involvement of SNAREs in Sey1p-dependent ER fusion was further supported by the physical interaction of Sey1p with Sec22p and Ufe1p, another ER SNARE. Furthermore, our estimation of the concentration of Sey1p on isolated microsomes, together with the lack of fusion between Sey1p proteoliposomes even with a 25-fold excess of the physiological concentration of Sey1p, suggests that Sey1p requires additional factors to support ER fusion in vivo. Collectively, our data strongly suggest that SNARE-mediated membrane fusion is involved in atlastin-initiated homotypic ER fusion.     

Flavobacterium qiangtangensis sp. nov., Isolated from Qiangtang Basin in Qinghai-Tibetan Plateau,China

A flexirubin-type yellow-pigmented, non-gliding, non-flagellated, gram-negative bacterium strain, designated F3^T, was isolated from a drilling core sample of the Qiangtang basin, Qinghai-Tibetan plateau, China. Phylogenetic analysis based on 16S rRNA gene sequences showed that the strain F3^T belongs to the genus Flavobacterium, with the highest 16S rRNA gene sequence similarity to the Flavobacterium noncentrifugens CGMCC 1.10076^T (94.92 %). Strain F3^T grew optimally at temperature about 20 °C, at pH about 7.0–8.0, at NaCl concentration 0 % (w/v). The DNA G+C content of the isolate was 35.5 mol%. The major polar lipid was phosphatidylethanolamine, predominant cellular fatty acids of the strain was iso-C_15:0 (22.02 %), while the major menaquinone was menaquinone 6. Due to the phenotypic and genetic distinctiveness and several other characteristic studied in this article, we consider F3^T as a novel species of the genus Flavobacterium, and propose to name it Flavobacterium qiangtangensis sp. nov. The type strain is F3^T (=CGMCC 1.12706^T = JCM 19739^T).     

Effect of Transient Cerebral Ischemia on the Expression of Receptor for Advanced Glycation End Products (RAGE) in the Gerbil Hippocampus Proper

The receptor for advanced glycation end products (RAGE) is a multi-ligand receptor of the immunoglobulin superfamily that has been implicated in multiple neuronal and inflammatory stress processes. In this study, we examined changes in RAGE immunoreactivity and its protein levels in the gerbil hippocampus (CA1-3 regions) after 5 min of transient global cerebral ischemia. The ischemic hippocampus was stained with cresyl violet, neuronal nuclei (a neuron-specific soluble nuclear antigen) antibody and Fluoro-Jade B (a marker for neuronal degeneration). 5 days after ischemia–reperfusion, delayed neuronal death occurred in the stratum pyramidale of the CA1 region. RAGE immunoreactivity was not detected in any regions of the CA1-3 regions of the sham-group; the immunoreactivity was markedly increased only in the CA1 region from 3 days after ischemia–reperfusion. On the other hand, RAGE immunoreactivity was newly expressed in astrocytes, not in microglia. Western blot analysis showed that RAGE protein level was highest at 5 days post-ischemia. In brief, both the RAGE immunoreactivity and protein level were distinctively increased in astrocytes in the ischemic CA1 region from 3 days after transient cerebral ischemia. These results indicate that the increase of RAGE expression in astrocytes after ischemia–reperfusion may be related to the ischemia-caused activation of astrocytes in the ischemic CA1 region.