Effect of Lincocin Treatment on the Greening Process in Bean (Phaseolus vulgaris) Leaves

The effect of lincocin (a plastid protein synthesis inhibitor) treatment on the greening process of bean (Phaseolus vulgaris L.) leaves have been studied. In comparison with control leaves treated ones had a decreased rate of chloroplast development. They had a marked chlorophyll deficiency and a decreased chlorophyll a/b ratio. Some long and short wavelength forms of chlorophyll a were lacking as evidenced from the absorption spectra at 25°C and the fluorescence spectra at 77°K. The –¹⁴CO₂ fixation was inhibited by 80–90% in treated leaves. The fluorescence induced by the measuring light was greater in the treated leaves than in the control ones, and the kinetics of the decline of the relative fluorescence intensity were also different. Electron microscopic studies showed macrogranum-like structures and incomplete membrane vesicles in the treated plastids. After longer treatment a destruction of membranes was observed. The results indicate some structural and functional membrane deficiencies and instability of the membranes.     

Growth Requirements of San Francisco Sour Dough Yeasts and Bakers' Yeast

The growth requirements of several yeasts isolated from San Francisco sour dough mother sponges were compared with those of bakers' yeast. The sour dough yeasts studied were one strain of Saccharomyces uvarum, one strain of S. inusitatus, and four strains of S. exiguus. S. inusitatus was the only yeast found to have an amino acid requirement, namely, methionine. All of the yeasts had an absolute requirement for pantothenic acid and a partial requirement for biotin. Inositol was stimulatory to all except bakers' yeast. All strains of S. exiguus required niacin and thiamine. Interestingly, S. inusitatus, the only yeast that required methionine, also needed folic acid. For optimal growth of S. exiguus in a molasses medium, supplementation with thiamine was required.     

Morphometry of nuclear and nucleolar structures in a CaCo-2 cell line

The number of the nucleoli in a CaCo-2 cell nucleus does not generally depend on the quantity of DNA in the nucleus, but nucleolar DNA content is directly proportional to total nuclear DNA. However, in multinucleolar cells (three or more nucleoli), the nucleolar DNA content increases after 96 h incubation in culture without concomitant quantitative changes in nuclear DNA. The percentage of multinucleolar cells and the average number of nucleoli per nucleus increase with increasing incubation time. After 72 and 96 h in culture, multinucleolar cells show distinctive morphologies. The ratio of the sum of nucleolar perimeters to the nuclear perimeter increases linearly when the number of nucleoli in a nucleus increases, but there is no concomitant increase in total nucleolar area or DNA content, except in the 72 and 96 h populations. When the number of nucleoli in CaCo-2 cells increases after 48 and 60 h in culture, the amount of DNA per nucleolus decreases.     

细胞因子基因转导对人乳腺癌细胞MHC抗原及细胞膜糖蛋白表达的影响

为探讨细胞因子基因(人IL-2、IL-6)转导对于肿瘤细胞膜MHC抗原及细胞膜糖蛋白表达调控的影响,本文利用脂质体介导的方法,将含人IL-6、IL-2基因的逆转录病毒载体分别导入人乳腺癌细胞系MCF-7细胞中,采用间接免疫荧光染色流式细胞仪测定法,对基因转导的瘤细胞细胞膜糖蛋白及MHC抗原表达进行测定。结果表明经两种基因修饰的MCF-7细胞MHCⅠ型抗原表达均获得增强,此外,基因转导细胞可程度不同地表现出细胞膜多种糖蛋白表达的变化。提示肿瘤细胞膜抗原及糖蛋白表达的改变可能是细胞因子基因转导影响肿瘤细胞免疫原性的重要结构基础。     

海南俄贤岭石灰岩山地海南大戟灌丛群落研究

根据样方调查,对海南俄贤岭自然保护区海南大戟灌丛群落的种类组成、外貌、结构特征和物种多样性进行分析。结果表明,在700m2样地中,有维管植物77种,隶属于47科70属。群落中乔木的个体数量很少,主要由灌木和草本组成,灌木层主要优势种为海南大戟等。群落外貌常绿,生活型以小高位芽为主,占22.08%;按照Raunkiaer的频度等级定律,属于B级的种类最多,频度值为43.42。整个群落的物种丰富度Magarlef指数为8.56,Shannon-Wiener指数为1.38,Simposon为0.90,均匀度指数为0.32。群落各层次的丰富度格局表现为灌木层>草本层>乔木层>藤本植物,多样性格局为灌木层>乔木层>草本层<(>)藤本植物,均匀度格局为乔木层>藤本植物>灌木层>草本层。     

海南鹦哥岭自然保护区的珍稀濒危植物与保育

对鹦哥岭的珍稀濒危植物进行野外调查表明,本区共有野生分布的珍稀濒危植物79种,隶属于47科71属。其中属于1999年国家重点一级保护4种,如海南苏铁(Cycas hainansis)、坡垒(Hopea hainansis)、台湾苏铁(Cy-cas taiwaniana)和伯乐树(Bretschneidera sinensis),国家二级保护14种。建议将18种列入国家保护名录中,20种列入省级保护名录,其中有30种为海南特有种。鹦哥岭珍稀濒危植物面临的威胁主要有原始森林面积的减少、人为毁林开荒和分布区限制。针对珍稀濒危植物的现状和受到的威胁,提出了应重点加强保护的6个地点及相应的保护对策和建议。     

海南省粗叶木属新记录植物五种

报道发现于海南省鹦哥岭的粗叶木属(Lasianthus Jack)海南省新记录种5种,并描述了它们的主要辨认特征。其中4种(华南粗叶木Lasianthus austrosinensis H.S.Lo、长梗粗叶木L.filipes Chun ex H.S.Lo、西南粗叶木L.henryi Hutch.、台湾粗叶木L.formosensis Matsum.)在与海南邻近的广东省与广西壮族自治区均有记录,而大叶粗叶木L.rigidus Miq.则在热带亚洲具有明显的间断性分布。     

实时荧光定量PCR及其在传染性疾病检测中的应用

实时荧光定量PCR技术被广泛应用于实验研究、临床检测中。与普通的PCR相比,实时荧光定量PCR技术具有特异性强、灵敏度高、重复性好、定量准确、速度快、全封闭反应等优点。我们综述了实时荧光定量PCR技术的原理、定量方法,及其在传染性疾病检测研究中的应用。     

Anisomycin诱导小鼠艾氏腹水癌细胞凋亡

目的：探讨Anisomycin诱导EAC细胞凋亡的机制。方法：利用MTT法观察Anisomycin对EAC细胞增殖的影响;应用An．nexinV—FITC和PI双染色检测Anisomycin作用下EAC细胞凋亡的变化;琼脂糖凝胶电泳检测Anisomycin作用下EAC细胞的DNA断裂片断;采用RT—PCR检测Anisomycin作用下Caspase-3mRNA的转录水平;WesternBlot分析Anisomycin处理的EAC细胞内Caspase-3蛋白的表达。结果：Anisomycin对EAC细胞增殖的抑制率随浓度的升高而增高,EAC细胞的凋亡水平也上升,随着Anisomycin浓度升高EAC细胞DNA断裂的寡核苷酸片段亦越趋明显,Caspase-3的mRNA和蛋白水平也上调,并明显高于阿霉素组。结论：结果表明,Anisomycin能够抑制EAC细胞的增殖,在体外可能通过激活Caspase-3凋亡信号而诱导EAC细胞的凋亡。     

提高检验医学本科实习生综合素质探讨

随着生物医学技术、计算机技术、物理化学技术的迅速发展,临床医学对检验医学提出了更高的要求。作为实验室工作人员,在保证结果准确的基础上,还应对临床医生及病人提出的疑问给予合理、正确地解释。此外,还应该具备和临床医生进行交流,以及合理处理病人投诉的能力。五年制检验医学本科生是检验医学的主力军,培养高素质的检验医学本科生,对检验医学的发展将起关键性作用。