miR-16-5p Is a Stably-Expressed Housekeeping MicroRNA in Breast Cancer Tissues from Primary Tumors and from Metastatic Sites

For quantitative microRNA analyses in formalin-fixed paraffin-embedded (FFPE) tissue, expression levels have to be normalized to endogenous controls. To investigate the most stably-expressed microRNAs in breast cancer and its surrounding tissue, we used tumor samples from primary tumors and from metastatic sites. MiRNA profiling using TaqMan^® Array Human MicroRNA Cards, enabling quantification of 754 unique human miRNAs, was performed in FFPE specimens from 58 patients with metastatic breast cancer. Forty-two (72%) samples were collected from primary tumors and 16 (28%) from metastases. In a cross-platform analysis of a validation cohort of 32 FFPE samples from patients with early breast cancer genome-wide microRNA expression analysis using SurePrintG3 miRNA (8 × 60 K)^® microarrays from Agilent^® was performed. Eleven microRNAs could be detected in all samples analyzed. Based on NormFinder and geNorm stability values and the high correlation (rho ≥ 0.8) with the median of all measured microRNAs, miR-16-5p, miR-29a-3p, miR-126-3p, and miR-222-3p are suitable single gene housekeeper candidates. In the cross-platform validation, 29 human microRNAs were strongly expressed (mean log2-intensity > 10) and 21 of these microRNAs including miR-16-5p and miR-29a-3p were also stably expressed (CV < 5%). Thus, miR-16-5p and miR-29a-3p are both strong housekeeper candidates. Their Normfinder stability values calculated across the primary tumor and metastases subgroup indicate that miR-29a-3p can be considered as the strongest housekeeper in a cohort with mainly samples from primary tumors, whereas miR-16-5p might perform better in a metastatic sample enriched cohort.     

天然优良葡萄酒酵母发酵特性研究

以实验室保藏的16株葡萄酒酵母为供试菌株,通过模拟酒精发酵初筛获得发酵力强、产酒度高或产香好的酵母5株。以2株商品酵母为对照,采用杜氏管发酵法研究其对NaCl、SO2、酒精、酸碱、温度和高糖的耐受性。结果表明,所有菌株在SO2200～600 mg/L、葡萄糖400～600 g/L浓度范围内都能发酵产气,且在pH1.5～13.0范围内可生长,其中有5株最高耐NaCl为100 g/L以及22%vol的乙醇、2株耐温最高达70℃。葡萄酒酿造结果显示,菌株Y-6发酵酒度高于2个商品酵母,总酸和挥发酸低,且其发酵葡萄酒具有浓郁的果香且香气持久、口感协调,有望应用于特色葡萄酒生产中。     

高温型红曲霉培养温度及保藏条件浅析

对从郎酒厂高温大曲中分离出的14株高温型红曲霉的培养温度和保藏条件进行了初步研究。结果表明,①高温型红曲霉在其生长温度方面有其特殊性;②高温型红曲霉在干燥条件下室温保藏较好。     

Fluctuation of Global Gene Expression by Endogenous miRNA Response to the Introduction of an Exogenous miRNA

Most of the intracellular endogenous microRNAs (endo-miRNAs) are considered to be saturated in Argonaute (Ago) proteins in the RNA-induced silencing complexes (RISCs). When exogenous miRNAs (exo-miRNAs) are introduced into cells, endo-miRNAs in the RISC may be replaced with exo-miRNAs or exo-miRNAs, and endo-miRNAs might also compete for the position in the newly synthesized RISC with each other. This would lead to the fluctuation of global gene expression not only by repression of exo-miRNA target gene expression, but also by the increase of the endo-miRNA target gene expression. In the present study, we quantified the changes in the expression levels of target genes of exo-miRNA and endo-miRNA in the cells transfected with fifteen different exo-miRNAs by microarray experiments. Different exo-miRNAs increased ratios of expression levels of target genes of a given endo-miRNA to different extents, suggesting that the replacement efficiencies might differ according to the exo-miRNA types. However, the increased ratios in the expression levels of each endo-miRNA target genes by the transfection of any particular exo-miRNA were mostly equivalent, suggesting that the endo-miRNAs present in the RISC might be replaced with excessive exo-miRNAs at similar levels, probably because they exist in single-stranded forms in the RISC.     

Chemically Synthesized 58‐mer LysM Domain Binds Lipochitin Oligosaccharide

Recognition of carbohydrates by proteins is a ubiquitous biochemical process. In legume–rhizobium symbiosis, lipochitin oligosaccharides, also referred to as nodulation (nod) factors, function as primary rhizobial signal molecules to trigger root nodule development. Perception of these signal molecules is receptor mediated, and nod factor receptor 5 (NFR5) from the model legume Lotus japonicus is predicted to contain three LysM domain binding sites. Here we studied the interactions between nod factor and each of the three NFR5 LysM domains, which were chemically synthesized. LysM domain variants (up to 58 amino acids) designed to optimize solubility were chemically assembled by solid‐phase peptide synthesis (SPPS) with microwave heating. Their interaction with nod factors and chitin oligosaccharides was studied by isothermal titration calorimetry and circular dichroism (CD) spectroscopy. LysM2 showed a change in folding upon nod factor binding, thus providing direct evidence that the LysM domain of NFR5 recognizes lipochitin oligosaccharides. These results clearly show that the L. japonicus LysM2 domain binds to the nod factor from Mesorhizobium loti, thereby causing a conformational change in the LysM2 domain. The preferential affinity for nod factors over chitin oligosaccharides was demonstrated by a newly developed glycan microarray. Besides the biological implications, our approach shows that carbohydrate binding to a small protein domain can be detected by CD spectroscopy.     

牛肉中孕酮的气相色谱/燃烧炉/同位素比质谱检测

建立了牛肉中孕酮的气相色谱/燃烧炉/同位素比质谱(GC/C/IRMS)检测方法。牛肉样品用乙腈振荡和超声辅助提取,经Na Cl脱水,有机相离心和旋转蒸发后以Zn Cl2脱脂,然后用LC-C18、LC-Si、LC-NH2固相萃取柱净化,过滤液经半制备液相色谱(Pre-HPLC)的C18柱纯化,最后分析物以GC/C/IRMS系统分析。牛肉中加标外源性孕酮δ13C值为-30.64±0.24‰(n=6),牛肉内源性孕酮δ13C值为-25.70±0.13‰(n=6),单因素方差分析(ANOVA,p值=2.23×10-140.05)显示,内源性孕酮和外源性孕酮的δ13C值存在显著差异性,且牛肉中加标外源性孕酮δ13C值与孕酮标准溶液的δ13C值无差异性。同时,经模拟实验可知,实际样品中内外源性孕酮混合物的δ13C值与外源性孕酮的δ13C值具有同源性。结果表明,本方法特异性和准确性好,GC/C/IRMS是鉴别激素来源的有效工具,该方法填补了国内鉴别激素来源技术空白。     

小麦表面微生物总DNA提取方法的比较与改进

对小麦表面微生物总DNA提取方法进行了探讨，从液氮冻融，裂解剂，蛋白酶K的加入，缓冲液等方面对SDS与SDS／CTAB两种方法加以改进。结果表明，改进后SDS法提取的DNA降解现象与纯度有很大改善，量也有所增加；SDS／CTAB法改进后浓度与提取率明显增加，纯度也较高。两种方法改进后提取的DNA分子量大小都集中在23kb左右，且不经纯化可直接扩增出16SrRNA基因。     

浅谈种曲制作技术

种曲质量的好坏直接影响到酱油成品质量的优劣，本简述了种曲的制造方法，对如何降低种曲杂菌数进行讨论。     

新疆油田微生物开采稠油技术研究及矿场试验

通过室内筛选复壮,选育出对克拉玛依稠油具有显著降粘作用的微生物菌种.室内降粘实验结果表明,菌种对稠油的降粘率可达70%,同时菌种可以改善稠油的流体性质.原油族组分分析结果表明,菌种能够降解稠油中的非烃和长链饱和烃.首次在克拉玛依油田进行了6口井的微生物吞吐开采稠油矿场试验,累计增油865t.