Study of the biosynthesis of 1-octen-3-ol using a crude homogenate of Agaricus bisporus in a bioreactor

ABSTRACT:  1-Octen-3-ol and 10-oxo- trans -8-decenoic acid are metabolites of the breakdown of linoleic acid (LA) by mushroom enzymes. These compounds can be produced in a bioreactor using a crude mushroom homogenate and the exogenous addition of LA and oxygen. The factors' duration of blending, mushroom–buffer ratio, effect of a surfactant, whole against partially clarified reaction broths, purity of LA, and utilization of stumps instead of whole mushrooms were studied for their effect on reaction yield using a 1-L bioreactor. The results showed the feasibility of using the more inexpensive 60%-pure LA instead of the 99%-pure LA even when a yield loss was involved. Waste stumps could be used instead of whole mushrooms with a yield decline of 26%.     

真丝无缝针织内衣的开发

在针织机上利用CAD系统,采用真丝,锦丝与锦／氨包覆丝开发真丝无缝针织内衣获得成功,文中介绍了生产真丝无缝针织内衣的设计思路及所采取的一些技术措施。     

Peptides from the N-terminal end of bovine lactoferrin induce apoptosis in human leukemic (HL-60) cells

To determine the effects of the multifunctional iron-binding glycoprotein, lactoferrin (LF) and related compounds on the growth of leukemic cells, human myeloid leukemic cells (HL-60) were exposed to bovine lactoferrin (bLF) and proteolytic hydrolysates of bLF. Pepsin hydrolysates of bLF showed a greater growth suppressive effect than tryptic hydrolysates or mature bLF. Four peptides with proliferation inhibition activity were purified from pepsin hydrolysates by ion-exchange chromatography, reverse-phase HPLC, and gel-filtration. All peptides were from the N-terminal end, in a region where lactoferricin B (Lfcin B), an antibacterial peptide, is located. Among the four peptides, peptide 1 (pep1) was found to exhibit highest activity and corresponded to residues 17 to 38 of bLF, with a molecular weight of 2753.88. The IC50 value of this peptide was 6.3 micrograms/ml. Three other peptides were less active and corresponded to sequences 1 to 16 and 45 to 48, linked by disulfide-bridge (pep2, molecular mass of 2430.13), 1 to 15 and 45 to 46 linked by disulfide bridge (pep3, molecular mass of 2017,92) and from residues 1 to 13 (pep4, molecular mass of 1558.73). Cell proliferation inhibition activity of the peptides was thought to be due to induction of apoptosis, which was evaluated by DNA ladder formation, DNA fragmentation, enhanced expression of phosphatidyl serine, and morphological changes. The IC50 values of the three peptides were confirmed using synthetic peptides and were consistent with those of purified peptides.     

基于STM8单片机的分区墨量控制系统设计

为提高胶印机墨量控制系统的稳定性和控制精度,提出了一款以STM8S208MB单片机为主控芯片、以直流减速电机为控制对象的电机控制系统,并设计了完整的硬件电路、上位机软件以及下位机程序。此方法可以实现用PC机在线监测所有墨键位置信息,并直接通过RS485总线向单片机发送指令,通过单片机控制直流减速电机的正反转动,以实现对墨键开度的精准调节。经测试,此系统驱动性能良好,抗干扰能力强,能够达到设计要求。     

铅和镉对牦牛肾脏细胞的影响

为了揭示牦牛肾脏细胞在重金属胁迫下的毒理性影响,在培养出的肾脏细胞中加入不同浓度的重金属离子铅（Pb²+）和镉（Cd²+）,提取总RNA,在逆转录酶的作用下生成c DNA,利用实时荧光定量技术检测牦牛肾脏细胞中金属硫蛋白mRNA的相对表达量。结果显示,将牦牛肾脏细胞中加入重金属浓度为0μmol/L的值设定为对照组,2^-ΔΔCt值设为1时,加入重金属铅的不同浓度0、5、10、20、30μmol/L的样品相对定量五种不同浓度的样品的2^-ΔΔCt分别为0.489、0.603、0.796、3.031;添加镉的五种不同浓度的样品的2^-ΔΔCt分别为5.280、3.530、8.110、11.630。通过差异性显著分析得出当重金属离子铅（Pb²+）和镉（Cd²+）添加10μmol/L时对肾脏细胞的生长有明显的抑制作用,相应的金属硫蛋白mRNA表达量较高,通过mRNA相对表达量的比较得出重金属镉的毒性比铅强,当重金属的添加量比较低时,重金属离子通过结合MT降低对肾脏细胞的毒害作用。      

人参皂苷F2干预Caspase级联反应抑制H2O2诱导的细胞凋亡

本研究探讨了人参皂苷F2对H_2O_2诱导人胚肾HEK-293细胞损伤的抗凋亡作用。利用试剂盒测定凋亡细胞Caspase-6和Caspase-9活性水平,应用WesternBlot检测凋亡细胞中Bcl-2凋亡家族(Bcl-2和Bax)与Caspase凋亡家族(CleavedCaspase-3和Cleaved PARP)的蛋白表达量。H_2O_2损伤细胞后,Caspase酶活力提高,促凋亡蛋白表达提高;1.25、5、20μmol/L F2预处理损伤细胞后,Caspase-6和Caspase-9活力呈浓度依赖性降低(p0.05),当F2浓度达到20μmol/L时,Caspase-6活性降低了6.83 U/mg protein,Caspase-9活性降低了5.88U/mgprotein;CleavedCaspase-3和CleavedPARP蛋白表达量显著低于损伤组(p0.05),随着F2浓度的升高,Cleaved Caspase-3表达量分别下降至280.90%、232.46%、185.26%,Cleaved PARP表达量随着F2浓度升高而降低至110.36%、85.85%、61.95%;F2高浓度组的Bcl-2/Bax比值(73.94%)较损伤组比显著提升(p0.05)。表明人参皂苷F2可以抑制凋亡蛋白Caspase的活性,降低Bax促凋亡蛋白与Caspase家族上、中、下游蛋白的表达,通过调控Caspase级联反应抑制H_2O_2刺激引起的细胞凋亡。     

In vitro bioaccessibility,bioavailability and plasma protein interaction of polyphenols from Annurca apple (M. pumila Miller cv Annurca)

The in vitro bioaccessibility, bioavailability and plasma protein interaction of polyphenols from Annurca apple and other conventional cultivars were evaluated. Salivary digestion concentrated into the medium 27–35% of native apple polyphenols, suggesting the potential bioavailability through the oral mucosal epithelium of significant amounts of bioactive compounds that could be gastric sensitive and/or poorly absorbed in the intestine. Annurca flesh revealed the highest content and provided the best intestinal bioaccessibility and bioavailability of oligomeric procyanidins among all of the apple peel and flesh tested. Since 49.4% of native procyanidins were not absorbed, they are expected to accumulate in the intestinal lumen where a potential inhibition capacity of cellular cholesterol uptake could be assumed. The permeated procyanidins (6.7% of their native pattern, 12.0% of intestinal procyanidins) significantly bound (58.7%) to plasma HDLs, suggesting a major role in cholesterol metabolism. Our results would indicate Annurca apple and its potential nutraceuticals as effective in the regulation of plasma cholesterol levels.     

常压室温等离子体诱变选育高产核黄素枯草芽孢杆菌

该研究以BS120作为出发菌株,通过常压室温等离子体诱变(atmospheric and room temperature plasma,ARTP)技术进行诱变处理,第一轮以40 mg/L 8-氮鸟嘌呤为筛选拮抗物进行筛选,得到核黄素产量和得率分别提升61. 60%和58. 12%的菌株BSG1。第二轮诱变以300 mg/L寡霉素为筛选拮抗物进行筛选,筛选获得菌株BSG3,核黄素产量和得率较BS120分别提升83. 59%和78. 76%。将核黄素操纵子表达质粒pMX45转入BSG3中,得到菌株BSG5,核黄素产量达到(4 467. 08±99. 47) mg/L,得率为(42. 56±1. 25) mg/g葡萄糖,较BS120分别提高140. 94%和120. 52%,展现了良好的核黄素发酵性能和遗传稳定性。     

A study of microstructure and performance of cast Fe–8Cr–2B alloy

The effects of quenching temperature on microstructure and hardness of cast Fe–8Cr–2B alloy containing 0.3 wt% C, 2.0 wt% B, 8.0 wt% Cr, 0.6 wt% Si, and 0.8 wt% Mn were investigated by optical microscopy (OM), scanning electron microscopy (SEM), X‐ray diffraction (XRD), Rockwell hardness and Vickers microhardness testers. The experimental results indicate that the as‐cast microstructure of cast Fe–8Cr–2B alloy consists of M₂B (M = Fe, Cr), M₇(C, B)₃, α‐Fe, and γ‐Fe. The dendritic matrix composed of lath martensite mixed with a small amount of retained austenite, and the netlike boride M₂B distribute in the grain boundary. After quenching between 950 °C and 1100 °C, the netlike eutectic boride are broken up and a new phase‐M₂₃(C, B)₆ which is distributed in the shape of sphere or short rod‐like are precipitated from the matrix. Both the macrohardness and microhardness of specimens increase with the increasing quenching temperature. At about 1050 °C, the hardness reaches the maximum value. However, when the temperature exceeds 1050 °C, the hardness will decrease slightly. With the increase of tempering temperature, the hardness of cast Fe–8Cr–2B alloy quenching from 1050 °C decreases gradually and its impact toughness increases slightly. Crusher hammer made of cast Fe–8Cr–2B alloy quenching from 1050 °C and tempering from 300 °C has good application effect, and its service life improves by 150–180% than that of high manganese steel hammer.     

Effect of strain waveform on creep-fatigue life for Sn–8Zn–3Bi solder

This paper describes the creep‐fatigue life of Sn–8Zn–3Bi under push–pull loading. Creep‐fatigue tests were carried out using Sn–8Zn–3Bi specimens in fast–fast, fast–slow, slow–fast, slow–slow and hold–time strain waveforms. Creep‐fatigue lives in the slow–slow and hold‐time waveforms showed a small reduction from the fast–fast lives but those in the slow–fast and fast–slow waveforms showed a significant reduction from the fast–fast lives. Conventional creep‐fatigue life prediction methods were applied to the experimental data and the applicability of the methods was discussed. Creep‐fatigue characteristics of Sn–8Zn–3Bi were compared with those of Sn–3.5Ag and Sn–37Pb.