A SERS-based immunoassay with highly increased sensitivity using gold/silver core-shell nanorods

An integrated platform for a very sensitive detection of cocaine based on a refractometric biosensor is demonstrated. The system uses a waveguide grating biosensor functionalized with a cocaine multivalent antigen-carrier protein conjugate. The immunoassay scheme consists of the competitive binding of cocaine-specific antibodies to the immobilized conjugates. A 1000-fold enhancement of the sensor's sensitivity is achieved when using gold conjugated monoclonal antibodies instead of free antibodies. Together with the optimization of the assay conditions, the setup is designed for a quick identification of narcotics using automated sampling. The results show that the presence of cocaine in a liquid sample could be identified down to a concentration of 0.7 nM within one minute. This value can be reduced even further when longer binding time is allowed (0.2 nM after 15 min). Application of the system to detection of narcotics at airport security control points is discussed.     

砂仁不同叶位叶片的光合作用和氧化胁迫

衰老时砂仁叶片Pmax降低,这与叶片Gs、Chi含量和可溶性蛋白质含量的降低有关.随着叶片的衰老,NPQ、AQY、F/Fm、φPsIl和qp均降低,热耗散减少,光抑制加剧,衰老后期出现光破坏.但这些参数下降的幅度均小于Pmax下降幅度.光暗反应失衡,活性氧生成增加.衰老初期(老化)叶片MDA含量没有升高,衰老中后期叶片MDA含量显著升高,表明老化叶片能有效地耗散或清除活性氧,衰老叶片则不能,尽管其sOD、APX和POD等抗氧化酶活力显著升高.上述结果表明砂仁叶片老化与氧化胁迫关系不大,衰老与氧化胁迫密切相关.     

湖泊底泥磷释放影响因素显著性试验分析

通过底泥正交模拟实验分析认为,温度、溶解氧、pH值和水动力均是影响双龙湖底泥磷释放的显著因素,各因素水平间有显著差异;影响因素显著性排序从大到小依次为溶解氧、温度、pH值、水动力;提高双龙湖水体的溶解氧水平是降低底泥磷释放的有效手段.     

Methylation-based molecular margin analysis in hepatocellular carcinoma

The positive surgical margins are associated with postsurgical recurrence in hepatocellular carcinoma patients, and molecular margin analysis is considered more sensitive in detecting preneoplastic lesions than conventional histological margin examination. To evaluate the feasibility of methylation-based molecular margin analysis in HCC and explore its clinical application, we investigated CDKN2A methylation status in the surgical margins of 20 HCC patients using a nested BS-MSP protocol and compared the methylation patterns in resection margins with those in the corresponding tumor and adjacent nonmalignant tissues. The results showed that a considerable frequency (35%, 7 of 20) of CDKN2A methylation was present in histologically negative margins, and methylation pattern analysis might be valuable for studying the cellular origin of recurrent carcinoma. Therefore, methylation-based molecular surgical margin analysis offers a promising tool in prognosis for HCC patients who underwent hepatectomy.     

Pimpinella rhomboidea var. tenuiloba is a synonym of Melanosciadium bipinnatum (Apiaceae)

Based on field investigations, as well as investigation of relevant specimens, Pimpinella rhomboidea var. tenuiloba is shown to be conspecific with Melanosciadium bipinnatum. The distribution and habitat of M. bipinnatum is redescribed and notes on the taxonomy of the species are presented.     

Receptor dimerization dynamics as a regulatory valve for plasticity of type I interferon signaling

Type I interferons (IFNs) activate differential cellular responses through a shared cell surface receptor composed of the two subunits, IFNAR1 and IFNAR2. We propose here a mechanistic model for how IFN receptor plasticity is regulated on the level of receptor dimerization. Quantitative single-molecule imaging of receptor assembly in the plasma membrane of living cells clearly identified IFN-induced dimerization of IFNAR1 and IFNAR2. The negative feedback regulator ubiquitin-specific protease 18 (USP18) potently interferes with the recruitment of IFNAR1 into the ternary complex, probably by impeding complex stabilization related to the associated Janus kinases. Thus, the responsiveness to IFNα2 is potently down-regulated after the first wave of gene induction, while IFNβ, due to its ∼100-fold higher binding affinity, is still able to efficiently recruit IFNAR1. Consistent with functional data, this novel regulatory mechanism at the level of receptor assembly explains how signaling by IFNβ is maintained over longer times compared with IFNα2 as a temporally encoded cause of functional receptor plasticity.     

Exon 9 skipping of apoptotic caspase-2 pre-mRNA is promoted by SRSF3 through interaction with exon 8

Alternative splicing plays an important role in gene expression by producing different proteins from a gene. Caspase-2 pre-mRNA produces anti-apoptotic Casp-2S and pro-apoptotic Casp-2L proteins through exon 9 inclusion or skipping. However, the molecular mechanisms of exon 9 splicing are not well understood. Here we show that knockdown of SRSF3 (also known as SRp20) with siRNA induced significant increase of endogenous exon 9 inclusion. In addition, overexpression of SRSF3 promoted exon 9 skipping. Thus we conclude that SRSF3 promotes exon 9 skipping. In order to understand the functional target of SRSF3 on caspase-2 pre-mRNA, we performed substitution and deletion mutagenesis on the potential SRSF3 binding sites that were predicted from previous reports. We demonstrate that substitution mutagenesis of the potential SRSF3 binding site on exon 8 severely disrupted the effects of SRSF3 on exon 9 skipping. Furthermore, with the approach of RNA pulldown and immunoblotting analysis we show that SRSF3 interacts with the potential SRSF3 binding RNA sequence on exon 8 but not with the mutant RNA sequence. In addition, we show that a deletion of 26 nt RNA from 5′ end of exon 8, a 33 nt RNA from 3′ end of exon 10 and a 2225 nt RNA from intron 9 did not compromise the function of SRSF3 on exon 9 splicing. Therefore we conclude that SRSF3 promotes exon 9 skipping of caspase-2 pre-mRNA by interacting with exon 8. Our results reveal a novel mechanism of caspase-2 pre-mRNA splicing.     

露天煤矿排土场边坡植被组成特征及其群落稳定性评价

研究植被恢复过程中植物群落组成、结构及稳定性的变化,可进一步了解到植物群落的演替过程及规律。采用空间代时间的方法对内蒙古锡林郭勒盟北电胜利露天煤矿4个排土场边坡人工恢复植被进行群落调查,在此基础上采用多样性指数与优化后的M.Godron稳定性指数对植物物种组成、物种多样性及其群落稳定性进行分析,探究不同恢复年限排土场边坡植被在恢复过程中群落特征及稳定性变化特征。结果表明：（1）排土场边坡植物物种组成共有16科44属56种,植物群落组成较简单,其中禾本科种类最多,生长型以草本植物为主。（2）随着恢复年限的增加,植物生活型由一、二年生转变为多年生,坡面优势种由人工种植植物转变为本土植物。（3）整体看,随着恢复年限增加,物种多样性呈下降趋势,群落稳定性整体呈上升趋势。（4）由于不同坡向土壤微环境差异,北坡恢复效果及稳定性好于南坡。本研究在一定程度上可为露天煤矿排土场边坡人工修复过程中植物物种及合理配置模式的选择提供科学依据。     

Genotype and haplotype analysis of the AZGP1 gene in cattle

Zinc-a2-glycoprotien (AZGP1) involved in lipid metabolism and associated with adipose tissue atrophy in cachexia. And it also related to sperm motility and in turn fertilization. To ascertain whether there were mutations in the bovine AZGP1 gene, this study investigated variation of the AZGP1 gene through PCR-SSCP and sequencing. Four missense mutations were identified in 649 cattle from six independent populations. Haplotype frequencies and linkage disequilibrium (LD) coefficients of these SNPs in three Chinese indigenous cattle breeds were analyzed. One LD block was found in three cattle breeds. The statistical analyses indicated that AC genotype of Z4 locus was associated with the high body weight, body length and chest girth in Jiaxian cattle breed (P?<?0.05). Our results provided evidence that polymorphisms in the AZGP1 gene were associated with growth traits, and may be used for marker-assisted selection and management in cattle breeding program.