The relationship between fungiform papillae density and detection threshold for sucrose in the young males

The aim of this study was to investigate the relationship offungiform papillae density with taste detection thresholds forsucrose of young male adults. One hundred and eighty two subjectsaged 18–23 years (mean age: 21.9 ± 1.2 years) wereincluded. The densities of fungiform papillae were recordedwith the aid of the digital camera, and the taste detectionthresholds for sucrose were detected using a modified forced-choicetriangle test. The mean density of papillae within all 170 statisticparticipants was 92.43 ± 2.64/cm², for the 6-mm-diameterstained section of the tongue tip. The average detection thresholdwas 10.83 ± 0.24 mmol/l, and the highest and lowest detectionthresholds were 19.88 ± 1.31 and 5.85 ± 0.43 mmol/l,respectively. Also, an inverse correlation between the fungiformpapillae density and the detection threshold was observed.     

FMDV VP1基因与HSP70基因在毕赤酵母中的融合表达及免疫特性

利用毕赤酵母系统对O型口蹄疫病毒VP1基因与结核杆菌HSP70基因进行融合表达,并检测此融合蛋白对小鼠细胞免疫和体液免疫的影响。将人工合成的O型口蹄疫病毒VP1基因与结核杆菌HSP70基因克隆入酵母表达载体pPICZαA中,以电穿孔法转化酵母菌X-33,用Zeocin YPDS平板筛选重组子,经甲醇诱导表达后,SDS-PAGE和免疫印迹分析表达产物。以皮下接种的方式给小鼠进行3次免疫,同时设两组对照,分别免疫PBS和常规灭活疫苗,然后通过MTT法和ELISA分别检测淋巴细胞的增殖情况和抗体水平。结果表明融合蛋白既能诱导细胞免疫应答又能诱导体液免疫应答,其诱导产生的抗体水平略低于常规灭活疫苗,而细胞免疫水平则高于后者。     

香兰素生物合成的研究进展

香兰素是一种十分重要的香料,在较多行业中用途广泛。天然来源的香兰素受诸多因素的限制,不能满足市场需求,因此化学法合成的香兰素是主要原料来源。近年来,随着自然资源的不断枯竭以及人们对环境保护意识的增强,通过微生物转化适宜的底物生物合成香兰素逐渐变为研究热点。本文综述了以丁香酚、异丁香酚和阿魏酸为底物的细菌、真菌生产香兰素的相关研究进展,阐述丁香酚、异丁香酚、阿魏酸产香兰素代谢途径的研究,以及生物技术在这一领域的运用。香兰素的生物合成具有广阔的发展和市场应用前景。     

Transgenic expression of phytase and acid phosphatase genes in alfalfa (Medicago sativa) leads to improved phosphate uptake in natural soils

Alfalfa (Medicagosativa L.) is one of the most widely grown crops in the USA. Phosphate (P) deficiency is common in areas where forage crops are grown. To improve the use of organic phosphate by alfalfa, two Medicagotruncatula genes, phytase (MtPHY1) and purple acid phosphatase (MtPAP1), were overexpressed in alfalfa under the control of the constitutive CaMV35S promoter or the root-specific MtPT1 promoter. Root enzyme activity analyses revealed that although both genes lead to similar levels of acid phosphatase activities, overexpression of the MtPHY1 gene usually results in a higher level of phytase activity than overexpression of the MtPAP1 gene. The MtPT1 promoter was more effective than the CaMV35S promoter in regulating gene expression and extracellular secretion under P-deficient conditions. Measurement of growth performance of the transgenic lines further proved that the best promoter-gene combination is the MtPHY1 gene driven by the MtPT1 promoter. Compared to the control, the plants with high levels of transgene expression showed improved growth. The biomass of several transgenic lines was three times that of the control when plants were grown in sand supplied with phytate as the sole P source. When the plants were grown in natural soils without additional P supplement, the best performing transgenic lines produced double the amount of biomass after 12?weeks (two cuts) of growth. Transgene effects were more obvious in soil with lower pH and lower natural P reserves than in soil with neutral pH and relatively higher P storage. The total P concentration in leaf tissues of the high-expressing transgenic lines was significantly higher than that of the control. The transgenes have great potential for improving plant P acquisition and biomass yield in P-deficient agricultural soils. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11032-011-9628-0) contains supplementary material, which is available to authorized users.     

CHIR-99021与FGF8协同诱导人表皮干细胞牙向分化

人表皮干细胞(human keratinocyte stem cells, hKSCs)可作为上皮源性的成体干细胞应用于牙齿再生,但是其诱导效率较低.本研究利用小分子化合物CHIR-99021提高hKSCs的Wnt/β-catenin信号活性,再与具有诱导成牙潜能的小鼠牙胚间充质重组,构建嵌合体,并移植裸鼠肾囊膜下培养20 d. 将嵌合体组织切片,并利用组织染色和免疫组化等方法鉴定牙齿结构. 结果显示,经FGF8诱导处理的hKSCs与小鼠牙胚间充质构成的嵌合体的成牙率为27.80%,其中成釉率仅为40.00%;经CHIR 99021诱导处理的hKSCs与小鼠牙胚间充质构成的嵌合体的成牙率仅为18.20%,其中成釉率高达100%;而CHIR 99021与FGF8协同作用,则进一步提高嵌合体成牙率至40.00%,其中成釉率也达75.00%. 进一步的研究发现,经CHIR-99021处理后,hKSCs的Wnt/β-catenin信号活性明显提高,同时FGF8的表达水平也显著上调. 以上结果表明,CHIR-99021可通过上调Wnt/β-catenin信号活性水平,同时促进FGF8表达,与FGF8协同,高效诱导hKSCs分化为具有分泌釉质功能的成釉质细胞. 研究结果对利用hKSCs作为上皮来源的成体细胞应用于人类牙齿再生的研究具有重要意义.     

中蜂的传粉作用研究

蜜蜂授粉在维持自然生态系统的平衡与发展过程中发挥着重要作用,也与农业生态系统中农作物的增产及品质提升有着密切联系.中蜂(中华蜜蜂Apis cerana cerana)是我国特有的蜜蜂遗传资源,广泛分布于除新疆以外的华南、中南、西南、西北、华北及东北等地区,野生资源丰富、民间饲养基础好,种群数量大,是本土开花植物的重要传...