A high-throughput screening method for improved R-2-(4-hydroxyphenoxy)propionic acid biosynthesis

Bioprocess and Biosystems Engineering - R-2-(4-hydroxyphenoxy)propionic acid (R-HPPA) is a key intermediate of the enantiomerically pure phenoxypropionic acid herbicides. R-HPPA could be...     

Subcellular proteome analysis of camptothecin analogue NSC606985-treated acute myeloid leukemic cells

We reported previously that NSC606985, a camptothecin analogue, induces apoptosis of acute myeloid leukemia (AML) cells through proteolytic activation of protein kinase Cdelta. Here, we analyzed protein expression profiles of fractionated nuclei, mitochondria, raw endoplasmic reticula, and cytosols of NSC606985-induced apoptotic AML cell line NB4 cells by two-dimensional electrophoresis combined with MALDI-TOF/TOF tandem mass spectrometry. In total, 90 unique deregulated proteins, including 16 compartment-compartment translocated ones, were identified. They contributed to multiple functional activities such as DNA damage repairing, chromosome assembly, mRNA processing, biosynthesis, modification, and degradation of proteins. More interestingly, several increased oxidative stress-related proteins mainly presented in mitochondria, while upregulated glycolysis proteins mainly occurred in the nuclei. With their functional analyses, the possible roles of these deregulated proteins in NSC606985-induced apoptosis were discussed. Collectively, these discoveries would shed new insights for systematically understanding the mechanisms of the camptothecin-induced apoptosis.     

Pancreaticoduodenal arterial rupture and hemoabdomen in ACI/SegHsd rats with polyarteritis nodosa

Many lesions associated with aging have been well-characterized in various strains of rats. Although documented in Sprague-Dawley and spontaneously hypertensive rats, polyarteritis nodosa has not previously been reported in ACI/SegHsd rats. ACII SegHsd rats were maintained on high-fat (40.5%), low-fat (11.6%), and high-fat to low-fat dietary protocols to examine the correlation between dietary fat and the regulation of prostate 5alpha-reductase gene expression and prostate cancer. Seven rats died unexpectedly with hemoabdomen and rupture of the pancreaticoduodenal artery secondary to polyarteritis nodosa (PAN). The purpose of this study was to analyze the pathologic findings in these and the remaining ACI/SegHsd rats and to correlate the level of dietary fat with the presence of PAN, arterial rupture, and hemoabdomen. Approximately 65% of the rats had evidence of PAN by histopathology, with a 24% incidence of arterial rupture. Additional lesions noted included an 88% incidence of chronic progressive nephropathy (CPN) and a 32% incidence of cartilaginous foci in the aortic valve. We found no association between the percentage of dietary fat and incidence of PAN, CPN, or cardiac cartilage. Although arterial rupture is a known complication of polyarteritis nodosa in humans, this case series is the first to document arterial rupture and hemoabdomen in rats with PAN.     

海南捕鸟蛛毒素及体液的抗菌活性研究

采用杯碟法研究了海南虎纹捕鸟蛛粗毒和体液对革兰氏阴性菌、阳性菌、霉菌和酵母的抑菌效果。结果表明,粗毒和体液均能抑制革兰氏阳性菌、阴性菌和霉菌的生长,但对酵母无抑制效果,并且粗毒和体液有一定的协同抗菌作用。     

Enantioselective hydrolysis of (R)-2, 2-dimethylcyclopropane carboxamide by immobilized cells of an R-amidase-producing bacterium, Delftia tsuruhatensis CCTCC M 205114, on an alginate capsule carrier

Immobilized cells of Delftia tsuruhatensis CCTCC M 205114 harboring R-amidase were applied in asymmetric hydrolysis of (R)-2, 2-dimethylcyclopropane carboxamide (R − 1) from racemic (R, S)-2, 2-dimethylcyclopropane carboxamide to accumulate (S)-2, 2-dimethylcyclopropane carboxamide (S − 1). Maximum R-amidase activity of 13.1 U/g wet cells (0.982 U/g beads) was obtained under conditions of 3% sodium alginate, 2.5% CaCl₂, 15 h crosslinking and 2 mm bead size, which was 53.9% of that of free cells (24.3 U/g wet cells). In addition, characterization of the immobilized cells was examined. The optimum R − 1 hydrolysis conditions were identified as follows: substrate concentration 10 mM, pH 8.5, temperature 35°C and time course 40 min. Under optimum conditions, the maximum yield and enantiomeric excess of (R)-2, 2-dimethylcyclopropanecarboxylic acid were 49.5% and >99%, respectively. This afforded S − 1 with a yield >49% and an e.e. of 97.7%. With good operational stability and excellent enanotioselectivity, the immobilized cells could be potentially utilized in industrial production of S − 1.     

Androgen stimulates endothelial cell proliferation via an androgen receptor/VEGF/cyclin A-mediated mechanism

Growing evidences support that androgen displays beneficial effects on cardiovascular functions although the mechanism of androgen actions remains to be elucidated. Modulation of endothelial cell growth and function is a potential mechanism of androgen actions. We demonstrated in the present study that androgens [dihydrotestosterone (DHT) and testosterone], but not 17β-estradiol, produced a time- and dose-dependent induction of cell proliferation in primary human aortic endothelial cells (HAECs) as evident by increases in viable cell number and DNA biosynthesis. Real-time qRT-PCR analysis showed that DHT induced androgen receptor (AR), cyclin A, cyclin D1, and vascular endothelial growth factor (VEGF) gene expression in a dose- and time-dependent manner. The addition of casodex, a specific AR antagonist, or transfection of a specific AR siRNA blocked DHT-induced cell proliferation and target gene expression, indicating that the DHT effects are mediated via AR. Moreover, coadministration of SU5416 to block VEGF receptors, or transfection of a specific VEGF-A siRNA to knockdown VEGF expression, produced a dose-dependent blockade of DHT induction of cell proliferation and cyclin A gene expression. Interestingly, roscovitine, a selective cyclin-dependent kinase inhibitor, also blocked the DHT stimulation of cell proliferation with a selective inhibition of DHT-induced VEGF-A expression. These results indicate that androgens acting on AR stimulate cell proliferation through upregulation of VEGF-A, cyclin A, and cyclin D1 in HAECs, which may be beneficial to cardiovascular functions since endothelial cell proliferation could assist the repair of endothelial injury/damage in cardiovascular system.     

兰州百合组培鳞茎发育研究

该研究以兰州百合商品种球鳞片为外植体材料,通过组织培养诱导丛生芽萌发及高频增殖,再以丛生芽为材料诱导其发育形成小鳞茎,调节培养基对小鳞茎进行膨大发育培养,最终形成促进兰州百合组培鳞茎膨大发育的“三步”组培培养技术路线;对发育过程中形成的丛生芽、小鳞茎及膨大鳞茎进行淀粉含量测定与生长特征参数统计,分析各步培养对鳞茎形成发育过程中淀粉含量与形态变化的影响。结果表明：所建立的“三步”培养方案培育出的组培鳞茎直径、重量与鳞片数分别为1.66 cm、2.48 g和26.33片,有效地促进了鳞茎的膨大,并能诱导鳞茎主茎杆的形成发育;在培养进程中其淀粉含量呈现逐步增加的趋势,这表明与鳞茎膨大发育正相关,同时鳞茎大小、重量及鳞片数三者也表现为正相关性;当鳞茎所含鳞片数在26片以上时,其生长点易发育形成主茎杆。该文研究了兰州百合组培鳞茎的形成与膨大发育技术,所研发的“三步”培养组成的鳞茎膨大发育组培技术有效地促进了鳞茎的膨大发育,而膨大发育的鳞茎能有效地缩短田间生长周期,从时间上提高百合生产量,同时为实现兰州百合膨大的鳞茎种球规模化生产提供技术支撑。     

Significantly enhanced production of acarbose in fed-batch fermentation with the addition of S-adenosylmethionine

Acarbose, a pseudo-oligosaccharide, is widely used clinically in therapies for non-insulin-dependent diabetes. In the present study, S-adenosylmethionine (SAM) was added to selected media in order to investigate its effect on acarbose fermentation by Actinoplanes utahensis ZJB- 08196. Acarbose titer was seen to increase markedly when concentrations of SAM were added over a period of time. The effects of glucose and maltose on the production of acarbose were investigated in both batch and fed-batch fermentation. Optimal acarbose production was observed at relatively low glucose levels and high maltose levels. Based on these results, a further fed-batch experiment was designed so as to enhance the production of acarbose. Fed-batch fermentation was carried out at an initial glucose level of 10 g/l and an initial maltose level of 60 g/l. Then, 12 h post inoculation, 100 micromol/l SAM was added. In addition, 8 g/l of glucose was added every 24 h, and 20 g/l of maltose was added at 96 h. By way of this novel feeding strategy, the maximum titer of acarbose achieved was 6,113 mg/l at 192 h. To our knowledge, the production level of acarbose achieved in this study is the highest ever reported.     

生物工程设备精品课程建设实践与探索

生物工程设备是现代工业生物技术转化为现实生产力和发挥作用的关键环节,随着工业生物技术的迅速发展,对掌握现代生物工程设备原理、设计和操作的人才的需求日益增加.本文分别从师资队伍建设、教材建设、教学内容及教学体系优化、教学方法革新等方面对生物工程设备精品课程建设经验进行了总结.     

红发夫酵母积累虾青素的代谢调控机理研究进展

由红发夫酵母合成的虾青素是一种非常有商业价值的类胡萝卜素.综述了近年来国内外在红发夫酵母中虾青素的生物合成途径、合成代谢调控机理等领域的相关研究进展,并提出了国内应开展的相关创新性研究.