贵阳地区蝉花微生态系统中细菌种群结构与功能

【目的】探索自然生态下蝉花内菌核、菌膜和环境细菌群落结构、功能及其相互关系。【方法】对细菌16S rRNA扩增片段进行高通量测序,分析贵阳市大将山和贵阳森林公园的蝉花内菌核、菌膜及其生境土壤的细菌群落组成、多样性及潜在功能。【结果】蝉花内菌核样本共检测到细菌562个属,菌膜样本521个属,菌际土样本578个属。两地的各组样本细菌群落结构相似,内菌核样本中假单胞菌属Pseudomonas、沙雷氏菌属Serratia占优势地位;菌膜样本中假单胞菌属和氨基杆菌属Aminobacter占优势;土壤样本以未分类的酸杆菌纲Acidobacteria和黄杆菌科Xanthobacteraceae为优势属。Venn图分析显示,菌际土样本包括了菌膜样本的大多数属,内菌核样本拥有较多的特有属,如沃尔巴克氏体属Wolbachia和立克次氏体Rickettsia等。PICRUSt功能预测结果显示,共计24个基因功能家族,主要与物质能量的代谢运输、细胞的行为发生及调控等功能相关。【结论】蝉花及其微生境中细菌具有丰富多样性,它们的潜在功能可能与营养物质的新陈代谢有关,对蝉花的个体生长发育有重要作用。研究结果对蝉花虫...     

萌发绿豆中水解大豆胰蛋白酶抑制子蛋白酶的纯化及固定化

大豆是豆类植物中最早发现存在蛋白酶抑制子的 ,由于其存在影响了豆类的利用价值 ,因此研究人员一直在寻找着解决办法。采用加热处理方法不能彻底钝化豆类蛋白的蛋白酶抑制子活性 ,且豆类蛋白的含硫氨基酸主要存在于各类蛋白酶抑制子中 ,从豆类蛋白中除去抑制子蛋白将大大降低其营养效价。本研究的目的是试图寻找一种可在常温下降解豆类胰蛋白酶抑制子的蛋白酶 ,从而钝化豆类的胰蛋白酶抑制活性。在前期工作中 ,我们发现枯草杆菌蛋白酶 (Ｓｕｂ ｔｉｌｉｓｉｎ)可在在常温下降解花生及大豆胰蛋白酶抑制剂[1] ,近期我们的研究表明 ,Ａｌｃａ…     

Antitumor promoting activities of 3-O-acyl-(-)epigallocatechins

As an exploratory investigation of antitumor promoting compounds, 3-O-acyl-(-)-epigallocatechins possessing a straight-, branched-, phenyl-inserted- or 1,4-phenylene-inserted-acyl chain of varying length from C4 to C18 were synthesized and evaluated their inhibitory effects against the activation of the Epstein-Barr virus early antigen (EBV-EA). It was indicated that the epigallocatechin derivatives having the straight- or branched-acyl chain of C8 to C11 carbon atoms achieve marked effects.     

EST analysis of gene expression in the tentacle of Cyanea capillata

Jellyfish, Cyanea capillata, has an important position in head patterning and ion channel evolution, in addition to containing a rich source of toxins. In the present study, 2153 expressed sequence tags (ESTs) from the tentacle cDNA library of C. capillata were analyzed. The initial ESTs consisted of 198 clusters and 818 singletons, which revealed approximately 1016 unique genes in the data set. Among these sequences, we identified several genes related to head and foot patterning, voltage-dependent anion channel gene and genes related to biological activities of venom. Five kinds of proteinase inhibitor genes were found in jellyfish for the first time, and some of them were highly expressed with unknown functions.     

Notch3 signaling in vascular smooth muscle cells induces c-FLIP expression via ERK/MAPK activation. Resistance to Fas ligand-induced apoptosis

Mutations in the Notch3 receptor result in the cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephelopathy (CADASIL) syndrome, a heritable arteriopathy predisposing to early onset stroke. Based upon clinical evidence that CADASIL arteriopathy results in degeneration and loss of vascular smooth muscle cells (VSMC) from the arterial wall, we postulated that Notch3 signaling is a critical determinant of VSMC survival. We initially established that both transient and constitutive Notch3 signaling promoted VSMC survival in response to the proapoptotic Fas ligand (FasL). Resistance to FasL-induced apoptosis was associated with the induction of c-FLIP, a primary inhibitor of the FasL signaling pathway. We determined that Notch3's regulation of c-FLIP was independent of the activity of the classical DNA-binding protein, RBP-Jk, but dependent upon cross-talk activation of the ERK/MAPK pathway. We extended our observations to the in vivo context by determining a coordinate regulation of Notch3 and c-FLIP within the arterial wall in response to injury. Furthermore, we defined that expression levels of Notch3 and c-FLIP are coordinately up-regulated within the neointima of remodeled arteries. Taken together, these findings provide initial evidence that Notch3 signaling may be a critical determinant of VSMC survival and vascular structure by modulating the expression of downstream mediators of apoptosis via signaling cross-talk with the ERK/MAPK pathway.     

Separation methods for taurine analysis in biological samples

Taurine plays an important role in a variety of physiological functions, pharmacological actions and pathological conditions. Many methods for taurine analysis, therefore, have been reported to monitor its levels in biological samples. This review discusses the following techniques: sample preparation; separation and determination methods including high-performance liquid chromatography, gas chromatography, ion chromatography, capillary electrophoresis and hyphenation procedures. It covers articles published between 1990 and 2001.     

Synthesis and energy transfer efficiency of FRET terminators derived from different linkers

A number of different energy transfer dye labeled-cassettes were synthesized using aminoacid based trifunctional linkers and coupled to the propargylamino-substituted dideoxynucleoside-5'-triphosphates (ddNTPs). These terminators were evaluated for their energy transfer efficiency and DNA sequencing potential using thermostable DNA polymerase.     

Five candidate biomarkers associated with the diagnosis and prognosis of cervical cancer

Purpose: Cervical cancer (CC) is one of the most general gynecological malignancies and is associated with high morbidity and mortality. We aimed to select candidate genes related to the diagnosis and prognosis of CC.Methods: The mRNA expression profile datasets were downloaded. We also downloaded RNA-sequencing gene expression data and related clinical materials from TCGA, which included 307 CC samples and 3 normal samples. Differentially expressed genes (DEGs) were obtained by R software. GO function analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of DEGs were performed in the DAVID dataset. Using machine learning, the optimal diagnostic mRNA biomarkers for CC were identified. We used qRT-PCR and Human Protein Atlas (HPA) database to exhibit the differences in gene and protein levels of candidate genes.Results: A total of 313 DEGs were screened from the microarray expression profile datasets. DNA methyltransferase 1 (DNMT1), Chromatin Assembly Factor 1, subunit B (CHAF1B), Chromatin Assembly Factor 1, subunit A (CHAF1A), MCM2, CDKN2A were identified as optimal diagnostic mRNA biomarkers for CC. Additionally, the GEPIA database showed that the DNMT1, CHAF1B, CHAF1A, MCM2 and CDKN2A were associated with the poor survival of CC patients. HPA database and qRT-PCR confirmed that these genes were highly expressed in CC tissues.Conclusion: The present study identified five DEmRNAs, including DNMT1, CHAF1B, CHAF1A, MCM2 and Kinetochore-related protein 1 (KNTC1), as potential diagnostic and prognostic biomarkers of CC.     

CD8+ T cells Are Preferentially Activated during Primary Low Dose Leishmania major Infection but Are Completely Dispensable during Secondary Anti-Leishmania Immunity

We previously showed that CD8⁺ T cells are required for optimal primary immunity to low dose Leishmania major infection. However, it is not known whether immunity induced by low dose infection is durable and whether CD8⁺ T cells contribute to secondary immunity following recovery from low dose infection. Here, we compared primary and secondary immunity to low and high dose L. major infections and assessed the influence of infectious dose on the quality and magnitude of secondary anti-Leishmania immunity. In addition, we investigated the contribution of CD8⁺ T cells in secondary anti-Leishmania immunity following recovery from low and high dose infections. We found that the early immune response to low and high dose infections were strikingly different: while low dose infection preferentially induced proliferation and effector cytokine production by CD8⁺ T cells, high dose infection predominantly induced proliferation and cytokine production by CD4⁺ T cells. This differential activation of CD4⁺ and CD8⁺ T cells by high and low dose infections respectively, was imprinted during in vitro and in vivo recall responses in healed mice. Both low and high dose-infected mice displayed strong infection-induced immunity and were protected against secondary L. major challenge. While depletion of CD4⁺ cells in mice that healed low and high dose infections abolished resistance to secondary challenge, depletion of CD8⁺ cells had no effect. Collectively, our results show that although CD8⁺ T cells are preferentially activated and may contribute to optimal primary anti-Leishmania immunity following low dose infection, they are completely dispensable during secondary immunity.