利用超临界CO2萃取回收β-胡萝卜素结晶脚料中有效组分的研究

应用超临界CO2萃取技术,从三孢布拉霉菌提取β-胡萝卜素后产生的结晶脚料中去除脂溶性杂质成分,以回收β-胡萝卜素.考察了萃取过程中温度(25 ℃～55 ℃)、压力(15 MPa～45 MPa)、时间(1.5 h～4.5h)对β-胡萝卜素的回收得率及产品含量的影响.结果表明,在萃取温度35 ℃、压力15 MPa、萃取时间...     

Translocating proline-rich peptides from the antimicrobial peptide bactenecin 7

The intracellular delivery of most peptides, proteins, and nucleotides to the cytoplasm and nucleus is impeded by the cell membrane. To allow simplified, noninvasive delivery of attached cargo, cell-permeant peptides that are either highly cationic or hydrophobic have been utilized. Because cell-permeable peptides share half of the structural features of antimicrobial peptides containing clusters of charge and hydrophobic residues, we have explored antimicrobial peptides as templates for designing cell-permeant peptides. We prepared synthetic fragments of Bac 7, an antimicrobial peptide with four 14-residue repeats from the bactenecin family. The dual functions of cell permeability and antimicrobial activity of Bac 7 were colocalized at the N-terminal 24 residues of Bac 7. In general, long fragments of Bac(1-24) containing both regions were bactericidal and cell-permeable, whereas short fragments with only a cationic or hydrophobic region were cell-permeant without the attendant microbicidal activity when measured in a fluorescence quantitation assay and by confocal microscopy. In addition, the highly cationic fragments were capable of traversing the cell membrane and residing within the nucleus. A common characteristic shared by the cell-permeant Bac(1-24) fragments, irrespective of their number of charged cationic amino acids, is their high proline content. A 10-residue proline-rich peptide with two arginine residues was capable of delivering a noncovalently linked protein into cells. Thus, the proline-rich peptides represent a potentially new class of cell-permeant peptides for intracellular delivery of protein cargo. Furthermore, our results suggest that antimicrobial peptides may represent a rich source of templates for designing cell-permeant peptides.     

CHO工程细胞株低血清培养的初探

以DMEM: F12(1: 1)为基础培养基,对CHO细胞的低血清培养进行了初步探索,降低培养基中血清含量,观察了细胞在10%、5%和1%等不同浓度低血清培养条件下生长状态和外源蛋白表达活性的变化.试验结果表明:在含1%血清的F12: DMEM(1: 1)培养基中,细胞仍能保持良好的生长状态,且培养上清中的目的蛋白活性与常规血清浓度10% DMEM培养条件下的活性接近.从而达到了既可以降低生产成本,又可以降低纯化难度的目的.     

Predictive value of circulating miR-328 and miR-134 for acute myocardial infarction

MicroRNA (miRNAs) is demonstrated to be present in the blood of humans and has been increasingly suggested as a novel biomarker for various pathological processes in the heart, including myocardial infarction, myocardial remodeling and progression to heart failure. In this study, we aim to evaluate the diagnostic and prognostic value of circulating miR-328 and miR-134 in patients with acute myocardial infarction (AMI). Circulating levels of miR-328 and miR-134 were detected by quantitative real-time PCR in plasma samples from 359 AMI patients and 30 healthy volunteers. Concentrations of high-sensitivity cardiac troponin T (hs-cTnT) were measured using electrochemiluminescence-based methods. MiRNAs were assessed for discrimination of a clinical diagnosis of AMI and for association with primary clinical endpoint defined as a composite of cardiogenic death and development of heart failure within 6 months after infarction. Results showed that levels of plasma miR-328 and miR-134 were significantly higher in AMI patients than in healthy controls. Receiver operating characteristic curve analyses showed significant diagnostic value of miR-328 and miR-134 for AMI. However, neither of them was superior to hs-cTnT for the diagnosis. Additionally, increased miRNA levels were strongly associated with increased risk of mortality or heart failure within 6 months for miR-328 (OR 7.35, 95 % confidence interval 1.07–17.83, P < 0.001) and miR-134 (OR 2.28, 95 % confidence interval 1.03–11.32 P < 0.001). In conclusion, circulating miR-328 and miR-134 could be potential indicators for AMI, and the miRNA levels are associated with increased risk of mortality or development of heart failure.     

基于mtCOII基因对山东省越冬代亚洲玉米螟不同种群的遗传结构分析

亚洲玉米螟Ostrinia furnacalis (Guenée)是我国重要农业害虫.为了全面揭示亚洲玉米螟遗传分化以及山东省亚洲玉米螟不同种群的遗传结构,对山东省越冬代亚洲玉米螟不同种群mtCOⅡ基因序列与来自GenBank的相关序列进行了遗传结构分析,并建立了鉴别不同遗传支系的PCR-RFLP方法.基于对340条mtCOⅡ序列的分析结果表明:所有样本共获得62个单倍型,其中单倍型17(H17)广泛分布于各种群之间,有6个单倍体型为山东种群所特有;亚洲玉米螟分化为2个遗传支系(支系Ⅰ与支系Ⅱ);2个遗传支系均在山东省发现,但以支系Ⅰ为主;亚洲玉米螟各单倍体型散布于山东省各地理种群中,缺乏明显的地理分布格局.山东亚洲玉米螟总体的单倍体型多样性指数Hd为0.695,种群内单倍型多样性指数在0.333-0.889之间;总体的核酸多样性指数π为0.00424,种群内核酸多样性指数在0.00061-0.00809之间.总群体的固定系数Fst为0.79421.AMOVA分析结果表明山东亚洲玉米螟的遗传分化主要来自于2个支系之间(79.42％).构建的亚洲玉米螟2个支系鉴别方法为其生物学与生态学的进一步研究奠定了基础.     

Colonization of endophyte Acremonium sp. D212 in Panax notoginseng and rice mediated by auxin and jasmonic acid

Endophytic fungi can be beneficial to plant growth. However, the molecular mechanisms underlying colonization of Acremonium spp. remain unclear.In this study, a novel endophytic Acremonium strain was isolated from the buds of Panax notoginseng and named Acremonium sp. D212. The Acremonium sp. D212 could colonize the roots of P. notoginseng,enhance the resistance of P. notoginseng to root rot disease, and promote root growth and saponin biosynthesis in P. notoginseng. Acremonium sp. D212 could secrete indole-3-acetic acid(IAA) and jasmonic acid(JA), and inoculation with the fungus increased the endogenous levels of IAA and JA in P. notoginseng. Colonization of the Acremonium sp. D212 in the roots of the rice line Nipponbare was dependent on the concentration of methyl jasmonate(Me JA)(2–15 μmol/L) and 1-naphthalenacetic acid(NAA)(10–20 μmol/L). Moreover, the roots of the JA signaling-defective coi1-18 mutant were colonized by Acremonium sp. D212 to a lesser degree than those of the wild-type Nipponbare and mi R393 boverexpressing lines, and the colonization was rescued by Me JA but not by NAA. It suggests that the cross-talk between JA signaling and the auxin biosynthetic pathway plays a crucial role in the colonization of Acremonium sp. D212 in host plants.     

互花米草入侵九段沙河口湿地对当地昆虫多样性的影响

为认识因互花米草(Spartinaalterniflora)入侵而给九段沙河口湿地昆虫多样性带来的影响,我们于2004年5月到2005年10月间用网捕和收割植株两种方法对3个典型植物群落中昆虫多样性作了连续调查。研究期间,共采集到昆虫11,300头。经鉴定为97个种,隶属于12目69科。互花米草群落中昆虫的物种数、个体数量以及Shannon-Wiener多样性指数均显著低于土著植物芦苇(Phragmitesaustralis)群落和海三棱藨草(Scirpusmariqueter)群落中的;而Simpson优势度指数较土著植物群落中高。聚类分析结果表明:芦苇与海三棱藨草群落中昆虫群落结构更为相似。互花米草的入侵将可能导致九段沙湿地昆虫多样性的降低和群落结构的改变。     

甲状腺激素对胸腺上皮细胞CK19蛋白表达的影响

目的探讨甲状腺激素对胸腺的发育的影响及可能的机制。方法将12只怀孕4d的大鼠随机分成A组和B组,A组正常饮水,B组孕鼠供以含有0．02％甲巯咪唑的饮水制备仔鼠甲状腺功能低下动物模型,将A组的仔鼠随机分成对照组和甲状腺素钠组,将B组的仔鼠随机分成甲低组和甲低＋甲状腺素钠组。甲状腺素钠组和甲低＋甲状腺素钠组于出生后15d给予腹腔注射甲状腺素钠（0．5mg／kg体重,1次／d）,连续给药25d。所有动物于出生后40d麻醉处死,测定仔鼠的胸腺重量及脏器指数;采用放射免疫技术测定仔鼠血清中三碘甲状腺原氨酸（triiodothyronine,T3）、四碘甲状腺原氨酸（tetraiodothyronine,T4）、促甲状腺激素（thyroid—stimulating hormone,TSH）水平,免疫组织化学技术检测胸腺上皮细胞细胞角蛋白19（cytokeratin 19,CK19）蛋白的表达量。结果与对照组比较,甲状腺素钠组仔鼠血清中T3、T4显著升高,TSH减少,胸腺重量增大;甲低组仔鼠血清中T3、T4明显降低,TSH显著增高,胸腺重量降低,胸腺上皮细胞CK19蛋白表达减少。与甲低组比较,甲低＋甲状腺素钠组仔鼠血清中T3、T4升高,TSH降低,胸腺指数增大,胸腺上皮细胞CK19蛋白的表达明显增多。结论甲状腺激素可以通过影响胸腺上皮细胞CK19的表达量,使胸腺发育或退化。