The synthesis of mycosporine-like amino acids (MAAs) by cultured, symbiotic dinoflagellates

We tested the hypothesis that there is a relation between phylotypes (phylogenetic types, as determined by restriction fragment length polymorphism (RFLP) and partial sequence analysis of the small subunit ribosomal RNA gene (SSUrDNA)) and the synthesis of mycosporine-like amino acids (MAAs) by symbiotic dinoflagellates under the influence of ultraviolet radiation (UV-B/A) and photosynthetically active radiation (PAR). We exposed 27 isolates of symbiotic dinoflagellates simultaneously to UV-B/A and PAR, and subsequently determined the MAAs present in cell extracts and in the media. The algae used included 24 isolates of Symbiodinium spp. originating from jellyfishes, sea anemones, zoanthids, scleractinians, octocorals, and bivalves, and three others in the genera Gymnodinium, Gloeodinium and Amphidinium from a jellyfish, an hydrocoral and a flatworm, respectively. In this study, all of the phylotype A Symbiodinium spp. synthesized up to three identified MAAs. None of the 11 cultured phylotypes B and C Symbiodinium spp. synthesized MAAs. The three non-Symbiodinium symbionts also synthesized up to three MAAs. The results support a conclusion that phylotype A Symbiodinium spp. have a high predilection for the synthesis of MAAs, while phylotypes B and C do not. Synthesis of MAAs by symbiotic dinoflagellates in culture does not appear to relate directly to depths or to the UV exposure regimes from which the consortia were collected.     

CC to TT mutation in the mitochondrial DNA of normal skin: relationship to ultraviolet light exposure

We have previously reported that ultraviolet (UV)-specific (CC to TT) mutations in p53 gene can be detected in normal skin. This, however, cannot be used as a cumulative marker of UV exposure, since cells with the p53 mutation acquire a clonal growth advantage. Moreover, a large skin biopsy is necessary for each assay. In order to circumvent these problems, we have measured mitochondrial (Mt) DNA mutations; there are more than 1000 copies of the Mt genome per cell, and Mt genes are not directly involved in cell growth. We have established a sensitive allele-specific polymerase chain reaction (AS-PCR) assay capable of detecting one CC to TT mutation in Mt DNA among 10(7) wild-type genes using a mismatch allele-specific primer. With this assay, we found no mutation-positive samples from internal non-exposed tissue (stomach, colon, and blood) (0/50). In contrast, 17 out of 111 skin samples were positive: the mutation frequency in positive samples was around 10(7)-10(-6) (10-100 copies of mutant in 10(8) wild-type Mt DNA). In normal skin tissue, the prevalence of positive samples was higher in those from exposed sites (13/51) than in those from less-exposed sites (1/26) (p<0.05). However, a quantitative correlation between sunlight exposure and the accumulation of mutations was not found. We conclude that the UV exposure-associated CC to TT mutation in Mt DNA can be detected in normal skin, but that further studies are required to develop this as a quantitative marker for UV exposure.     

功能化自组装肽水凝胶在细胞培养中应用

自组装肽水凝胶是一类能够在特定的条件下利用疏水作用、静电作用、氢键、范德华力等非共价作用力来形成内部高度有序结构的多肽分子凝胶.自组装多肽凝胶具有易于设计合成、低免疫原性、低炎症反应、良好组织相容性、生物利用度高等特点,可为各种细胞提供近似于天然的细胞外基质,促进细胞增殖、分化、黏附等细胞生物学行为.因此,自组装肽水凝...     

乳腺癌中雌激素受体α表达水平调节的分子机制

雌激素受体α(ERα)在乳腺癌的发生发展中扮演重要角色,因而ERα成为乳腺癌治疗的分子靶标。ERα的表达水平在乳腺癌患者中差异较大,即使同一患者,在乳腺癌的不同阶段也可能有很大的差别。乳腺癌内分泌治疗的疗效以及预后都与ERα表达水平密切相关。影响ERα表达水平的分子机制复杂,众多调节分子在染色质、转录、转录后、翻译和翻译后等水平参与ERα表达水平的调节。在染色质和转录水平,许多分子通过直接或间接地与ERα启动子的相互作用改变ERα的转录;在转录后/翻译水平,一些microRNA通过诱导ERαmRNA的降解和/或抑制其翻译降低ERα的水平;在翻译后水平,许多分子通过泛素-蛋白酶体途径调节ERα蛋白水平。文章从不同水平,对这些调节分子的调节机制进行简要综述。     

特种稻不育系巨胚813A的选育与研究

用350 Gy剂量的Co60-γ射线照射水稻三系保持系813B种子,获得巨胚突变体,命名为巨胚813B（简称813geB）。用巨胚813B回交813A育成特种稻不育系-巨胚813A（简称813geA）。对巨胚813B及巨胚813A的生物学特性进行研究,结果表明：巨胚813A与813A的主要农艺性状、雄性不育性及产量构成因素均无明显差异。巨胚813B与813B具有相似的农艺性状,但绝对胚重由0.61mg提高到1.36mg,相对胚重由2.70%提高到6.96%。巨胚813B糙米的蛋白质、粗脂肪、粗纤维及必需氨基酸含量均比813B高。其中蛋白质含量9.77%,比813B提高了8.80%;粗脂肪含量5.28%,比813B提高了87.23%;8种必需氨基酸含量均有提高。利用巨胚恢复系与巨胚813A可组配成巨胚杂交稻。     

住院医师/专科医师对规范化培训带教师资和培训管理的满意度调查分析

目的 调查参加规范化培训的住院/专科医师对带教师资综合职业能力和培训管理的满意度,进一步了解不同医院开展毕业后医学教育所面临的问题和进行毕业后医学教育规范化培训异同。方法 采用自制问卷对成都市4所三级甲等医院598名住院/专科医师进行问卷调查,对收集的数据进行因子分析和方差分析。结果 受调查的598名住院/专科医师对带教师资的综合职业能力的满意度评分在3.83～4.11之间﹝满分为5分﹞,而对培训管理的满意度评分在2.91～3.75之间,且不同医院住院/专科医师的满意度有差异性﹝P﹤0.05﹞。结论 无论教学医院还是非教学医院,都应加强带教师资建设和培训管理,才能提高住院/专科医师对规范化培训的满意度,以促进住院/专科医师规范化培训的顺利开展。     

Pescadillo抗体的制备及其表达研究

为深入研究Pescadillo的生物学功能及其在肿瘤发生过程中的潜在作用, 将该分子与GST融合表达, 融合蛋白经纯化、洗脱、免疫小鼠后获得其多克隆抗体, 运用抗体检测了Pescadillo分子的表达, 发现该分子的表达受雌激素的诱导; 该分子主要分布于乳腺、卵巢、小肠等细胞分裂旺盛的组织; 此外, 在人肾癌、肝癌、卵巢癌、结肠癌以及不同的乳腺癌细胞株中均发现Pescadillo的表达; 通过比较乳腺癌患者癌组织与癌旁组织中Pescadillo的表达水平发现, 它在癌组织中的表达水平显著增加. 以上结果表明, Pescadillo可能在肿瘤的发生、发展中具有重要作用, 是肿瘤诊断与治疗的潜在靶标