吸附剂及培养基组成对香荚兰细胞悬浮培养产生香兰素的影响

本文报道了培养基的组成及添加吸附剂对香荚兰细胞悬浮培养产生香兰素的影响。结果表明,添加吸附剂活性炭及XAD-2后,香荚兰细胞产生的香兰素含量明显增加,而且活性炭的效果优于XAD-2;香荚兰细胞在全组成的MS培养基中香兰素含量均低于由矿物质盐组成培养基中的含量。可以考虑采用二步培养法来培养香荚兰细胞及产生香兰素。     

Production of 3-hydroxypropionate homopolymer and poly(3-hydroxypropionate-co-4-hydroxybutyrate) copolymer by recombinant Escherichia coli

Conversion of 3-hydroxypropionate (3HP) from 1,3-propanediol (PDO) was improved by expressing dehydratase gene (dhaT) and aldehyde dehydrogenase gene (aldD) of Pseudomonas putida KT2442 under the promoter of phaCAB operon from Ralstonia eutropha H16. Expression of these genes in Aeromonas hydrophila 4AK4 produced up to 21 g/L 3HP in a fermentation process. To synthesize homopolymer poly(3-hydroxypropionate) (P3HP), and copolymer poly(3-hydroxypropionate-co-3-hydroxybutyrate) (P3HP4HB), dhaT and aldD were expressed in E. coli together with the phaC1 gene encoding polyhydroxyalkanoate (PHA) synthase gene of Ralstonia eutropha, and pcs' gene encoding the ACS domain of the tri-functional propionyl-CoA ligase (PCS) of Chloroflexus aurantiacus. Up to 92 wt% P3HP and 42 wt% P3HP4HB were produced by the recombinant Escherichia coli grown on PDO and a mixture of PDO+1,4-butanediol (BD), respectively.     

Inhibition of severe acute respiratory syndrome virus replication by small interfering RNAs in mammalian cells

Severe acute respiratory syndrome (SARS) is an acute respiratory infectious disease that spread worldwide in early 2003. The cause was determined as a novel coronavirus (CoV), SARS-associated CoV (SARS-CoV), with a single-stranded, plus-sense RNA. To date, no effective specific treatment has been identified. To exploit the possibility of using RNA interference as a therapeutic approach to fight the disease, plasmid-mediated small interfering RNAs (siRNAs) were generated to target the SARS-CoV genome. The expression of siRNAs from two plasmids, which specifically target the viral RNA polymerase, effectively blocked the cytopathic effects of SARS-CoV on Vero cells. These two plasmids also inhibited viral replication as shown by titer assays and by an examination of viral RNA and protein levels. Thus, our results demonstrated the feasibility of developing siRNAs as effective anti-SARS drugs.     

Predictive value of circulating miR-328 and miR-134 for acute myocardial infarction

MicroRNA (miRNAs) is demonstrated to be present in the blood of humans and has been increasingly suggested as a novel biomarker for various pathological processes in the heart, including myocardial infarction, myocardial remodeling and progression to heart failure. In this study, we aim to evaluate the diagnostic and prognostic value of circulating miR-328 and miR-134 in patients with acute myocardial infarction (AMI). Circulating levels of miR-328 and miR-134 were detected by quantitative real-time PCR in plasma samples from 359 AMI patients and 30 healthy volunteers. Concentrations of high-sensitivity cardiac troponin T (hs-cTnT) were measured using electrochemiluminescence-based methods. MiRNAs were assessed for discrimination of a clinical diagnosis of AMI and for association with primary clinical endpoint defined as a composite of cardiogenic death and development of heart failure within 6 months after infarction. Results showed that levels of plasma miR-328 and miR-134 were significantly higher in AMI patients than in healthy controls. Receiver operating characteristic curve analyses showed significant diagnostic value of miR-328 and miR-134 for AMI. However, neither of them was superior to hs-cTnT for the diagnosis. Additionally, increased miRNA levels were strongly associated with increased risk of mortality or heart failure within 6 months for miR-328 (OR 7.35, 95 % confidence interval 1.07–17.83, P < 0.001) and miR-134 (OR 2.28, 95 % confidence interval 1.03–11.32 P < 0.001). In conclusion, circulating miR-328 and miR-134 could be potential indicators for AMI, and the miRNA levels are associated with increased risk of mortality or development of heart failure.     

Heterotic patterns in rapeseed (<Emphasis Type="Italic">Brassica napus</Emphasis> L.): I. Crosses between spring and Chinese semi-winter lines

Chinese semi-winter rapeseed is genetically diverse from Canadian and European spring rapeseed. This study was conducted to evaluate the potential of semi-winter rapeseed for spring rapeseed hybrid breeding, to assess the genetic effects involved, and to estimate the correlation of parental genetic distance (GD) with hybrid performance, heterosis, general combining ability (GCA) and specific combining ability (SCA) in crosses between spring and semi-winter rapeseed lines. Four spring male sterile lines from Germany and Canada as testers were crossed with 13 Chinese semi-winter rapeseed lines to develop 52 hybrids, which were evaluated together with their parents and commercial hybrids for seed yield and oil content in three sets of field trials with 8 environments in Canada and Europe. The Chinese parental lines were not adapted to local environmental conditions as demonstrated by poor seed yields per se. However, the hybrids between the Chinese parents and the adapted spring rapeseed lines exhibited high heterosis for seed yield. The average mid-parent heterosis was 15% and ca. 50% of the hybrids were superior to the respective hybrid control across three sets of field trials. Additive gene effects mainly contributed to hybrid performance since the mean squares of GCA were higher as compared to SCA. The correlation between parental GD and hybrid performance and heterosis was found to be low whereas the correlation between GCA_{(f + m)} and hybrid performance was high and significant in each set of field trials, with an average of r = 0.87 for seed yield and r = 0.89 for oil content, indicating that hybrid performance can be predicted by GCA_{(f + m)}. These results demonstrate that Chinese semi-winter rapeseed germplasm has a great potential to increase seed yield in spring rapeseed hybrid breeding programs in Canada and Europe.     

近岸海洋线虫与细菌、古菌的共现性及其对碳、氮循环的影响

【目的】初步探究海洋线虫与微生物的相互作用对碳、氮循环的影响。【方法】利用16S r RNA和18S r RNA基因高通量测序方法,对33个近岸沉积物样品中细菌、古菌和真核生物的多样性进行调查;对海洋线虫与细菌、海洋线虫与古菌的共现性进行网络分析,并采用Spearman统计学方法,识别出与海洋线虫共现性呈显著相关性的微生物种类。【结果】在夏季,红树林和潮间带泥滩样品中线虫OTU平均相对丰度基本呈随深度增加而递减趋势;冬季的红树林样品中发现相类似变化规律,只有在冬季潮间带泥滩样品中线虫OTU平均相对丰度在深层较高于表层。相对丰度最高的海洋线虫隶属于单宫目(47%)、色矛目(19%)、刺嘴目(16%)和垫刃目(9%),它们与热源体古菌、深古菌、γ-和δ-变形菌等微生物有显著正/负相关关系。【结论】在香港米埔湿地沉积物中,与相对丰度最高的5种线虫显著相关的几大类微生物均在碳、氮、硫等元素循环方面起十分重要的作用,暗示海洋线虫与微生物潜在的相互作用对元素地球化学循环具有重要影响。研究结果有助于深入了解线虫在生态系统中未被揭示的生态功能,有助于更清晰地认识海洋线虫在底栖生态系统中所扮演的角色。     

FBXW7 suppresses epithelial‐mesenchymal transition and chemo‐resistance of non‐small‐cell lung cancer cells by targeting snai1 for ubiquitin‐dependent degradation

Objectives

FBXW7 acts as a tumour suppressor by targeting at various oncoproteins for ubiquitin‐mediated degradation. However, the clinical significance and the involving regulatory mechanisms of FBXW7 manipulation of NSCLC regeneration and therapy response are not clear.

Materials and Methods

Immunohistochemical staining and qRT‐PCR were applied to detect FBXW7 and Snai1 expression in 100 samples of NSCLC and matched tumour‐adjacent tissues. FBXW7 manipulation of cancer biological functions were studied by using MTT assay, immunoblotting, flow cytometry, transwells, wound healing assay, and sphere‐formation assays. Immunofluorescence and co‐immunoprecipitation were used to analyse the possible interaction between Snai1 and FBXW7.

Results

We detected the decreased FBXW7 expression in majority of the NSCLC tissues, and lower FBXW7 level was correlated with advanced TNM stage. Furthermore, those patients with decreased FBXW7 expression tend to have both poorer 5‐year survival outcomes, and shorter disease‐free survival, comparing to those with higher FBXW7 levels. Functionally, we found that FBXW7 enforcement suppressed NSCLC progression by inducing cell growth arrest, increasing chemo‐sensitivity and inhibiting Epithelial‐mesenchymal Transition (EMT) progress. Results further showed that FBXW7 could interact with Snai1 directly to degrade its expression through ubiquitylating alternation in NSCLC, which could be partially abrogated by restoring Snai1 expression.

Conclusions

FBXW7 conduction of tumour suppression was partly through degrading Snai1 directly for ubiquitylating regulation in NSCLC

     

智力水平还是文化表现?——尼安德特人与现代人文化精致程度差异研究述评

尼安德特人和解剖学意义上的现代人在文化精致程度上的区别已经争论了很长时间,考古学者希望能得出一个确定的答案,两个假设应运而生:智力水平(尼人不能发展出精致的文化)与文化表现(尼人不需要发展出精致程度较高的文化)。古人类与考古材料显示智力水平假设有缺陷:尼人的基因进入了现代人的基因库中,而且他们有能力学习现代人的技术,在"过渡工业"的材料中可以找到相关证据;与此同时,至今还未找到关系到智力水平的大脑结构证据证明尼人智力水平不如现代人。检验文化表现假设的前提是尼人与早期现代人在智力水平上没有差异,却呈现出不同的社会网络和社会组织。本文在讨论尼人与现代人人口与社会交流的基础上,认为现代人复杂的社会组织切割了尼人的生活环境,同时火山爆发引起了资源短缺,最终导致了尼人在欧洲灭绝。     

原生动物伪红色双轴虫细胞纤毛器微管胞器的直接荧光标记

应用荧光紫杉醇直接荧光标记法显示,原生动物纤毛虫伪红色双轴虫(Diaxonellapseudorubra)细胞纤毛器微管中,口围带基部含小膜托架及与托架相联系的肋壁微管;额腹横棘毛基部含前纵微管束、后纵微管束、横微管束和周围微管束,其微管在不同棘毛基部的定向和发达程度不一;缘棘毛基部含前纵微管束、后纵微管束。细胞形态发生过程中,前仔虫口纤毛器微管独立发生于老口围带内侧,在细胞形态发生末期新纤毛器微管形成时,尚有部分老额棘毛、横棘毛和缘棘毛残存,此后老结构逐渐被吸收。结果表明,伪红色双轴虫的纤毛器基部微管的分化很可能具有种属级的特异性,新纤毛器微管分化过程中老结构可能具有定位和物质贡献作用。