对“观察霉菌”的实验教学设计与实施

介绍了对初中生物学教材中"观察酵母菌和霉菌"实验的教学设计和改进。主要是对观察青霉的改进,包括取材方法、培养材料和培养方法的改进等。     

对生化分离技术实验的探讨

实验教学的改进和提高,是教学改革的重要一环。阐述了作者在教学实践的过程中,对生化分离技术实验中的原料选取、处理方法、仪器设备等方面所作的改进尝试而取得的成效。     

生态足迹模型的争论与发展

生态足迹模型自William Rees1992年提出、Mathis Wackemagel 1996年推广应用以来,在众多研究者的质疑和争论中不断发展、完善。目前,国内已有许多综述文章详细介绍了其理论假设、基本概念、计算方法、实证应用、一些缺陷改进等。在这些综述成果基础上,结合近2～3年的研究新进展,概括了10a来对其理论假设、均衡因子、产量因子、计算方法、过于静态性、缺乏预测性、结论单一性等方面存在的主要争论,聚焦了在概念发展、计算方法、均衡因子、产量因子、应用领域、时间序列、非线性科学研究方法、与其他社会经济指标相结合等方面进行的改进及发展,并指出今后生态足迹模型研究将要在计算方法改进、加强实践操作及市场化运作、与可持续发展政策的有机联系、与非线性科学研究方法相结合、长时间序列动态评估、单项指标等方面取得重要进展。这些争论、改进的综述及发展方向的提出,目的在于引发国内对生态足迹模型研究的新思考,推动生态足迹模型理论的进一步完善和发展。     

真核生物mRNA差显技术(Differential Display)的研究进展

真核生物ｍＲＮＡ差显技术（ＤｉｆｅｒｅｎｔｉａｌＤｉｓｐｌａｙ）的创立及其对该技术的一系列改进,为研究与生殖、发育、细胞分化、癌变、病变、衰老、程序化死亡及抗逆性与抗病性等生命过程有关的基因的差异表达,以及有关基因的分子克隆提供了有效工具。本文简要概述差显技术的原理、优越性、主要缺陷、技术改进等方面的研究进展。     

“绿色植物的呼吸作用消耗氧气、产生二氧化碳”的实验创新设计

对"绿色植物的呼吸作用消耗氧气、产生二氧化碳"实验的形式、装置、方法、材料等方面进行了改进与创新。     

“酶的催化效率”实验的几种不同改进方式

浙科版"酶的催化效率"实验存在一些不足。从实验装置、实验试剂、实验步骤等方面对该实验进行改进,改进后的实验结果有3种呈现形式。改进后的实验更加科学合理,操作简单,实验结果更加直观有趣。     

2例生物学实验的改进

针对初中生物学2个实验,通过对实验材料器具、实验装置设计和实验操作过程等方面进行了改进,提高实验效果。     

快速、有效筛选新的功能基因——差异显示技术

真核生物mRNA差异显示技术 (DifferentialDisplay)的创立及其对该技术的一系列改进 ,为研究与生殖、发育、细胞分化、癌变、病变、衰老、程序化死亡及抗逆性与抗病性等生命过程有关的基因的差异表达 ,以及有关基因的分子克隆提供了有效工具。本文将简要叙述差异显示技术的优越性、主要缺陷、技术改进等方面的研究进展 ,和具体操作的注意事项。     

一步法快速质粒鉴定方法

对《分子克隆实验指南》(第三版)中的牙签法小量制备质粒DNA的方法做了改进,减少了 加样次数,免去冰浴、离心等步骤,改进后的方法在琼脂糖凝胶电泳前仅需一步加样和加热过程, 提高了实验效率。同时结合使用多孔道移液器和96孔板,更适合于在高通量筛选中鉴定阳性克 隆。实验对改进后的方法与《分子克隆实验指南》上的方法进行了比较,表明“一步法”的检测效 果、准确率与重复性均有到较好的结果。     

獐不同组织材料DNA提取的有效方法

根据野外采集的獐肌肉、皮张、毛发、血迹、骨骼和粪便等不同样本的特点采用相适合的DNA提取方法,并对肌肉、皮张、毛发、骨骼的提取进行了改进,通过对线粒体细胞色素b和控制区基因PCR扩增反应以及测序结果证实,这几种DNA抽提方法及相应改进的可靠性,并可以提高野外非损伤性取材在保护遗传学中的应用。     

A new fluorescent staining method for callose of microspore mother cells during meiosis

To observe the dynamic behavior of callose of microspore mother cells during meiosis, we developed a convenient, rapid and efficient staining method using an improved carbol fuchsin/aniline blue solution. The stained microspore mother cells during meiosis showed yellowish green callose, red cytoplasm and dark red chromosomes when excited with blue light, which produced a contrasting image with a three-dimensional effect. When stained with only improved carbol fuchsin solution, the cells had red cytoplasm and chromosomes when excited with green light. The improved carbol fuchsin solution can be used to replace other more expensive DNA-specific dyes, such as DAPI and H33258, to reduce experimental costs.     

A new fluorescent staining method for callose of microspore mother cells during meiosis

To observe the dynamic behavior of callose of microspore mother cells during meiosis, we developed a convenient, rapid and efficient staining method using an improved carbol fuchsin/aniline blue solution. The stained microspore mother cells during meiosis showed yellowish green callose, red cytoplasm and dark red chromosomes when excited with blue light, which produced a contrasting image with a three-dimensional effect. When stained with only improved carbol fuchsin solution, the cells had red cytoplasm and chromosomes when excited with green light. The improved carbol fuchsin solution can be used to replace other more expensive DNA-specific dyes, such as DAPI and H33258, to reduce experimental costs.     

Effect of culture conditions on monoclonal antibody production from genetically modified tobacco suspension cultures

Oxygen supply and inoculum age were found to affect the production of the heavy chain monoclonal antibody (HC MAb) from genetically modified tobacco suspension cultures. The increase of oxygen supply increased both cell growth and HC MAb production. Furthermore, the increased aeration and mixing improved the production of HC MAb based on the unit amount of cells or total soluble proteins. This indicated that the increased aeration improved the production and secretion of HC MAb more than other cell components. HC MAb production and cell growth also improved when batch cultures were inoculated with actively dividing cells (5-day old) rather than the fullygrown cells (7- or 10-day old cells) that are commonly used for subcultures. The addition of glutamine to the medium also improved cell growth and HC MAb production.     

XP-A cells complemented with Arg228Gln and Val234Leu polymorphic XPA alleles repair BPDE-induced DNA damage better than cells complemented with the wild type allele

Functional effects of Arg228Gln and Val2343Leu XPA polymorphisms on benzo[a]pyrene-r-7,t-8-dihydrodiol-t-9,10-epoxide-(+/-)-anti (BPDE) survival and repair were investigated in SV40 immortalized XP12RO cells complemented with wild type and polymorphic XPA cDNAs in an inducible cDNA expression system. In contrast to previous studies showing little impact of XPA polymorphisms on UV survival and repair, cells complemented with polymorphic XPAs displayed improved BPDE survival and repair as compared to wild type XPA-complemented cells. Survival after BPDE treatment was measured using AlamarBlue reduction and colony forming ability. Cells expressing low levels of either polymorphic XPA had equivalent or improved survival compared to wild type XPA-complemented cells (XPAwt cells). XPA induction improved BPDE survival in Arg228Gln (R228Q cells) and Val234Leu (V234L cells) complemented cells, but not XPAwt cells. BPDE-induced DNA damage repair was measured both by reactivation after transfection of a luciferase reporter plasmid reacted with BPDE in vitro, and by removal of adducts from genomic DNA of BPDE-treated cells. BPDE-induced DNA damage repair in R228Q and V234L cells expressing XPA at very low levels was similar to repair in XPAwt cells expressing XPA at normal levels. XPA induction improved repair in R228Q and V234L cells but not in XPAwt cells. Our findings suggest that both Arg228Gln and Val234Leu XPAs function better than wild type XPA for BPDE adduct removal. These observations differ from UV repair results suggesting that the differences are lesion specific. The location of the polymorphisms within the putative poly(ADP-ribose) binding domain suggests that poly(ADP-ribose) interaction is important in repair.     

Improvement of Raw Sausage Fermentation by Stress-Conditioning of the Starter Organism Lactobacillus sakei

Effective growth and high acidification activity during meat fermentation are key characteristics of starter lactobacilli to ensure hygienic safety and sensory quality of the product. In this study, we demonstrated that the performance of Lactobacillus sakei in sausage fermentation can be improved by preinoculation treatments with sublethal heat, cold, and salt stress. Sausages were produced and inoculated with stress-treated cells of L. sakei 23 K (pLPV111) and the isogenic mutant of the class III heat-shock repressor CtsR, which was previously shown to exhibit improved growth in fermenting sausages. The pH values of sausages fermented with stressed cells attained defined threshold values in a distinctly shorter time than those inoculated with unstressed cells. In particular, the cold-stressed cells (4 degrees C) reduced the pH to 5.0 within approximately 40 hours compared with approximately 70 hours for untreated cells. This enhanced acidification activity of the cold-stressed cells was consistent with an increased growth rate. Growth studies in culture medium showed that stress-treated cells with improved performance did not exhibit this advantage when exposed to curing salt, one of the major stressors at the beginning of sausage fermentation. Preinoculation stress treatment is a promising way to improve the effectiveness of meat starter lactobacilli.     

有机碳化合物对湛江等鞭金藻生长的影响

为了探讨有机碳化合物对湛江等鞭金藻的营养效应,实验设置了在f/2培养基中添加葡萄糖、乙酸钠、半乳糖、甘油、乙醇、柠檬酸钠和甘氨酸等7种有机碳化合物的处理,测定了湛江等鞭金藻(Isochrysis zhanjiangensis)的生长情况。结果表明,参试的7种有机碳化合物中,甘氨酸对湛江等鞭金藻细胞生长的促进作用最明显,而乙醇对藻细胞生长的促进效果不明显,其他5种均有不同程度的促进作用。7种有机碳对湛江等鞭金藻胞内蛋白质含量和总脂的积累量具有一定差异性影响。0.5～10g·L^-1的葡萄糖、乙酸钠均可提高胞内蛋白质和总脂的含量。半乳糖对总脂积累量的影响不明显。     

新生大鼠雪旺细胞原代培养方法改良

对常用的阿糖胞苷处理及差速贴壁法进行大鼠雪旺细胞原代培养及纯化的方法进行改进。先用阿糖胞苷处理杀死大部分的成纤维细胞,再用抗-Thy-1.1抗体和兔补体处理去除残余成纤维细胞,获得纯化的雪旺细胞。此外,我们对抗-Thy-1.1抗体和兔补体的浓度、处理时间等都进行了改进,避免了由于雪旺细胞状态不好而引起的大量雪旺细胞死亡。此方法能够将雪旺细胞的纯度由90%提高到99%。     

Use of an improved zirconyl hematoxylin stain in the diagnosis of Barrett's esophagus

Barrett's esophagus is a precancerous condition characterized by replacement of the normal stratified squamous epithelium by a simple columnar epithelium with goblet cells that secrete an acidic mucin. As originally formulated, fresh solutions of zirconyl hematoxylin stain goblet cells poorly. An improved formula, quintupling the amount of oxidant, yields zirconyl hematoxylin solutions that stain goblet cells darkly even when fresh. The improved zirconyl hematoxylin can be used in place of alcian blue in the diagnosis of Barrett's esophagus. The ingredients of zirconyl hematoxylin are always readily available and are generally recognized as safe.     

Improved activity of streptozotocin-selected insulinoma cells following microencapsulation and transplantation into diabetic mice

We have recently shown that repeated streptozotocin (STZ) treatment induces the selection of insulinoma cells (RINmS) with both improved resistance to diabetogenic toxins and functional activity, compared to parental RINm cells. The aim of the present study was to estimate the potential of RINmS cells to maintain their engineered characteristics during in vivo hyperglycemic conditions. It was found that microencapsulation and transplantation into diabetic mice preserved a three-fold higher level of insulin content in selected RINmS cells when compared to the parental ones. Retrieval of transplanted encapsulated cells from the peritoneal cavity of diabetic mice had a significantly higher insulin content and a more intense insulin response to secretogogues in selected RINmS cells when compared to retrieved RINm cells. In conclusion, our results show that RINmS cells do not lose their improved functional characteristics after encapsulation and transplantation into diabetic mice.     

Improvement of tolerance to freeze-thaw stress of baker's yeast by cultivation with soy peptides

The tolerance to freeze–thaw stress of yeast cells is critical for frozen-dough technology in the baking industry. In this study, we examined the effects of soy peptides on the freeze–thaw stress tolerance of yeast cells. We found that the cells cultured with soy peptides acquired improved tolerance to freeze–thaw stress and retained high leavening ability in dough after frozen storage for 7 days. The final quality of bread regarding its volume and texture was also improved by using yeast cells cultured with soy peptides. These findings promote the utilization of soy peptides as ingredients of culture media to improve the quality of baker’s yeast.