Determination of enantiomeric composition by negative-ion electrospray ionization-mass spectrometry using deprotonated N-(3,5-dinitrobenzoyl)amino acids as chiral selectors

The ability to use mixtures of deprotonated N-(3,5-dinitrobenzoyl)amino acids as chiral selectors for the determination of enantiomeric composition by electrospray ionization-mass spectrometry is demonstrated. For each experiment, two N-(3,5-dinitrobenzoyl)amino acids were chosen such that each would have opposite selectivity for the enantiomers of the analyte. Electrospray ionization-mass spectrometry, monitored in the negative ion mode, of solutions containing the two N-(3,5-dinitrobenzoyl)amino acids, sodium hydroxide, and the analyte, in a one-to-one mixture of methanol and water, afford peaks in the mass spectrum that correspond to the deprotonated 1:1 analyte-selector complexes. The ratio of the intensities of the complexes in the mass spectrum can be related to the enantiomeric composition of the analyte. Additionally, the sense and extent of chiral recognition is consistent with chromatographic observations, using chiral stationary phases derived from N-(3,5-dinitrobenzoyl)amino acids. Each analysis of enantiomeric composition requires less than 10 s to complete, indicating that this method has great potential for the development of fast-/high-throughput chiral analyses.     

Lectin-Like Oxidized LDL Receptor-1 Is an Enhancer of Tumor Angiogenesis in Human Prostate Cancer Cells

Altered expression and function of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) has been associated with several diseases such as endothelial dysfunction, atherosclerosis and obesity. In these pathologies, oxLDL/LOX-1 activates signaling pathways that promote cell proliferation, cell motility and angiogenesis. Recent studies have indicated that olr1 mRNA is over-expressed in stage III and IV of human prostatic adenocarcinomas. However, the function of LOX-1 in prostate cancer angiogenesis remains to be determined. Our aim was to analyze the contribution of oxLDL and LOX-1 to tumor angiogenesis using C4-2 prostate cancer cells. We analyzed the expression of pro-angiogenic molecules and angiogenesis on prostate cancer tumor xenografts, using prostate cancer cell models with overexpression or knockdown of LOX-1 receptor. Our results demonstrate that the activation of LOX-1 using oxLDL increases cell proliferation, and the expression of the pro-angiogenic molecules VEGF, MMP-2, and MMP-9 in a dose-dependent manner. Noticeably, these effects were prevented in the C4-2 prostate cancer model when LOX-1 expression was knocked down. The angiogenic effect of LOX-1 activated with oxLDL was further demonstrated using the aortic ring assay and the xenograft model of tumor growth on chorioallantoic membrane of chicken embryos. Consequently, we propose that LOX-1 activation by oxLDL is an important event that enhances tumor angiogenesis in human prostate cancer cells.     

Evidence of mutualistic synzoochory between cryptogams and hummingbirds

Endozoochory is usually involved in seed dispersal mutualisms, whereas ectozoochory is non‐rewarding, and therefore neutral (or even negative) for the animal vector. Synzoochory is an intermediate dispersal type between endo and ectozoochory in which propagules are deliberately transported (usually in the mouth) but with no ingestion or gut passage involved. We present empirical evidence of synzoochoric mutualism between the hummingbird Sephanoides sephaniodes and cryptogams (one fern and seven moss species). Two species (Lophosoria quadripinnata and Ancistrodes genuflexa) constituted the bulk of nest biomass, and another six moss species were present in lesser quantity. The hummingbird was selective when collecting nest material so that the nests contained a higher density of reproductive structures (that could be dispersed further) than natural patches of the cryptogam species. Even after one year, the nests maintained half of the original reproductive structures (sporangia, sporophytes) and biomass, constituting an important dispersal source. These results show a new type of mutualism in which mosses could be dispersed throughout longer distances (several km) by hummingbirds and to higher positions (particularly for ground‐living species, promoting dispersal potential). The hummingbird benefits from collecting cryptogam material for nest building, and cryptogams benefit from the concentration and relocation of diaspore sources into more effective recruiting sites. Similar mutualistic relationships could be a general phenomenon, of importance in many ecosystems.     

华北蓟属植物的化学分类初探

本文对华北地区蓟属ＣｉｒｓｉｕｍＡｄａｎｓ．１６种植物的甲醇提取液紫外吸收光谱（ＵＶ）进行了比较研究。结果表明,蓟属植物的叶较其它部位的ＵＶ具有较好的稳定性和代表性,其光谱的特征可以作为属下分类的重要依据,其化学分类结果与形态分类基本一致。根据光谱特征,结合形态学及有关的细胞学和同工酶方面的资料,重新确立了Ｓｅｃｔ．Ｐｓｅｕｄｏ－Ｅｒｉｏｌｅｐｉｓ（Ｎａｋａｉ）Ｋｉｔａｍ．和Ｃ．ｓｅｇｅｔｕｍＢｇｅ．的组级和种级地位,最后,作者进一步讨论了光谱特征在化学分类中的意义。     

An Ensemble Method for Predicting Subnuclear Localizations from Primary Protein Structures

Background

Predicting protein subnuclear localization is a challenging problem. Some previous works based on non-sequence information including Gene Ontology annotations and kernel fusion have respective limitations. The aim of this work is twofold: one is to propose a novel individual feature extraction method; another is to develop an ensemble method to improve prediction performance using comprehensive information represented in the form of high dimensional feature vector obtained by 11 feature extraction methods.

Methodology/Principal Findings

A novel two-stage multiclass support vector machine is proposed to predict protein subnuclear localizations. It only considers those feature extraction methods based on amino acid classifications and physicochemical properties. In order to speed up our system, an automatic search method for the kernel parameter is used. The prediction performance of our method is evaluated on four datasets: Lei dataset, multi-localization dataset, SNL9 dataset and a new independent dataset. The overall accuracy of prediction for 6 localizations on Lei dataset is 75.2% and that for 9 localizations on SNL9 dataset is 72.1% in the leave-one-out cross validation, 71.7% for the multi-localization dataset and 69.8% for the new independent dataset, respectively. Comparisons with those existing methods show that our method performs better for both single-localization and multi-localization proteins and achieves more balanced sensitivities and specificities on large-size and small-size subcellular localizations. The overall accuracy improvements are 4.0% and 4.7% for single-localization proteins and 6.5% for multi-localization proteins. The reliability and stability of our classification model are further confirmed by permutation analysis.

Conclusions

It can be concluded that our method is effective and valuable for predicting protein subnuclear localizations. A web server has been designed to implement the proposed method. It is freely available at http://bioinformatics.awowshop.com/snlpred_page.php.     

Raman spectroscopy detects phenotypic differences among Escherichia coli enriched for 1‐butanol tolerance using a metagenomic DNA library

Advances in Raman spectroscopy are enabling more comprehensive measurement of microbial cell chemical composition. Advantages include results returned in near real‐time and minimal sample preparation. In this research, Raman spectroscopy is used to analyze E. coli with engineered solvent tolerance, which is a multi‐genic trait associated with complex and uncharacterized phenotypes that are of value to industrial microbiology. To generate solvent tolerant phenotypes, E. coli transformed with DNA libraries are serially enriched in the presence of 0.9% (v/v) and 1.1% (v/v) 1‐butanol. DNA libraries are created using degenerate oligonucleotide primed PCR (DOP‐PCR) from the genomic DNA of E. coli, Clostridium acetobutylicum ATCC 824, and the metagenome of a stream bank soil sample, which contained DNA from 72 different phyla. DOP‐PCR enabled high efficiency library cloning (with no DNA shearing or end‐polishing) and the inclusion un‐culturable organisms. Nine strains with improved tolerance are analyzed by Raman spectroscopy and vastly different solvent‐tolerant phenotypes are characterized. Common among these are improved membrane rigidity from increasing the fraction of unsaturated fatty acids at the expense of cyclopropane fatty acids. Raman spectroscopy offers the ability to monitor cell phenotype changes in near real‐time and is adaptable to high‐throughput screening, making it relevant to metabolic engineering.     

细胞色素P450scc在人早期胎盘中的表达（简报）

人妊娠期间,胎盘合成大量的类固醇激素,与妊娠的启动、维持、分娩以及胎儿的发育均存在密切的关系。阐明胎盘类固醇激素特别是孕酮合成与分泌的调节机制对于寻找理想的生育调控技术和生殖保健方法具有重要的意义。因此,胎盘类固醇激素合成与分泌的调节向来是生殖生物学与妇产科学领域所关注的焦点问题之一,     

Triptolide Inhibited Cytotoxicity of Differentiated PC12 Cells Induced by Amyloid-Beta25–35 via the Autophagy Pathway

Evidence shows that an abnormal deposition of amyloid beta-peptide_25–35 (Aβ_25–35) was the primary cause of the pathogenesis of Alzheimer’s disease (AD). And the elimination of Aβ_25–35 is considered an important target for the treatment of AD. Triptolide (TP), isolated from Tripterygium wilfordii Hook.f. (TWHF), has been shown to possess a broad spectrum of biological profiles, including neurotrophic and neuroprotective effects. In our study investigating the effect and potential mechanism of triptolide on cytotoxicity of differentiated rat pheochromocytoma cell line (the PC12 cell line is often used as a neuronal developmental model) induced by Amyloid-Beta_25–35 (Aβ_25–35), we used 3-(4, 5-dimethylthiazol-2-yl)-2, 5- diphenyltetrazolium bromide (MTT) assay, flow cytometry, Western blot, and acridine orange staining to detect whether triptolide could inhibit Aβ_25–35–induced cell apoptosis. We focused on the potential role of the autophagy pathway in Aβ_25–35-treated differentiated PC12 cells. Our experiments show that cell viability is significantly decreased, and the apoptosis increased in Aβ_25–35-treated differentiated PC12 cells. Meanwhile, Aβ_25–35 treatment increased the expression of microtubule-associated protein light chain 3 II (LC3 II), which indicates an activation of autophagy. However, triptolide could protect differentiated PC12 cells against Aβ_25–35-induced cytotoxicity and attenuate Aβ_25–35-induced differentiated PC12 cell apoptosis. Triptolide could also suppress the level of autophagy. In order to assess the effect of autophagy on the protective effects of triptolide in differentiated PC12 cells treated with Aβ_25–35, we used 3-Methyladenine (3-MA, an autophagy inhibitor) and rapamycin (an autophagy activator). MTT assay showed that 3-MA elevated cell viability compared with the Aβ_25–35-treated group and rapamycin inhibits the protection of triptolide. These results suggest that triptolide will repair the neurological damage in AD caused by deposition of Aβ_25–35 via the autophagy pathway, all of which may provide an exciting view of the potential application of triptolide or TWHF as a future research for AD.     

Influences of addition of different krilium in saline-sodic soil on the seed germination and growth of cabbage

China is one of the largest countries with huge amount of saline-sodic soil. How to ameliorate these lands is a hotspot in China. Through measurement of soil salinity, pH value and seed germination and growth status of cabbage seedlings, 17 kinds of krilium were added to experimented soil to evaluate their effects on amelioration of heavy saline-sodic soil. Firstly, among these 17 kinds of krilium, 11 (HPMA, gypsum, HEDP, T225, PAPEMP, MA-AA, ATMP, AA/AMPS, PAA, charcoal and BHMTPMPA) were effective agents and could effectively induce seed germination without any germination phenomena in the control saline-sodic soil. HPMA was the best one in ameliorating saline-sodic soil, which has been manifested by various indices of seed germination. Secondly, addition of gypsum together with other organic agents could strongly increase the ameliorative effectiveness if compared with relatively weak agents, while decrease seed germination if compared with the stronger agent of the 2 mixed agents, showing that the synergetic effect between gypsum and other kinds of tested krilium was not evident. Thirdly, optimum dosages for separate addition of HPMA and gypsum were 42.8 L m^?3 and 25 kg m^?3, while mixed-addition of these 2 agents at the same dosages did not cause plus effect in soil improvement. Finally, field application of HPMA could enhance the growth of cabbage seedlings at the first month, but began to wilt thereafter. Thus, instead of one-time addition, several-time addition of HPMA at the suitable dosage in field practice could strengthen the effectiveness of soil amelioration.