柠檬酸钠对L-亮氨酸发酵代谢流分布的影响

应用代谢流分析方法研究了柠檬酸钠对L-亮氨酸发酵中后期胞内代谢流分布的影响.结果表明:在L-亮氨酸分批发酵过程中,未添加柠檬酸钠时合成L-亮氨酸的代谢流量为25.4:在初始发酵培养基中添加2.0g·L-1柠檬酸钠后,合成副产物L-丙氨酸和HAc的代谢流量明显减少,分别降低了13.6%和63.4%,葡萄糖的供给受到限制,EMP途径代谢流从97.7减弱至87.1,而L-亮氨酸生物合成的代谢流增长至30.2,较未添加前提高了18.9%.因此发酵过程中添加柠檬酸钠能够改变L-亮氨酸生物合成途径的关键节点丙酮酸及乙酰辅酶A的代谢流分布,保持EMP和TCA之间代谢流量平衡,有利于减少副产物的生成,提高L-亮氨酸生物合成途径的代谢流量.     

不同氨基酸和植物油对替考拉宁产量及组分含量的影响

研究了氨基酸和植物油对替考拉宁产量和组分含量的影响。结果发现,与对照相比,在发酵培养基中添加0.05%异亮氨酸和0.05%L-缬氨酸,替考拉宁产量分别提高24.7%和38.2%;在发酵培养基中添加0.50%大豆油和0.50%玉米油,替考拉宁产量分别提高20.4%和28.7%。L-缬氨酸和大豆油在提高替考拉宁产量的同时,对主成分A2-2的影响作用是相反的,L-缬氨酸可以升高A2-2含量,而大豆油则降低A2-2含量。L-缬氨酸和大豆油的联合使用可进一步提高替考拉宁产量,当L-缬氨酸和大豆油添加量分别为0.06%、0.75%时,替考拉宁产量提高47.2%。优化后的配方经过50L发酵罐发酵验证,替考拉宁的平均发酵效价达到5 652U·mL~(-1),各组分含量均符合质量要求,主成分A2-2含量达到53.1%。     

可溶型非融合血管生长抑制因子Kringle 5基因工程菌发酵培养和诱导表达条件的优化

在实验室试管培养条件下优化了基因工程菌E.coli BL21（DE3）pET15b/K5发酵产可溶型非融合血管生长抑制因子Kringle 5的培养基和诱导表达条件。经菌体干重测定和SDS-PAGE检测,确定最佳培养基（g.L-1）为：胰蛋白胨10.0,酵母提取物5.0,NaCl 10.0,葡萄糖6.0,NH4Cl 2.6,NaH2PO45.0,Na2HPO46.0;优化的诱导表达条件为：诱导剂浓度0.01mmol.L-1,诱导时间6h,诱导温度37℃,摇床转速220r.min-1。在优化的培养基和诱导表达条件下,菌体干重为1.8g.L-1,Kringle 5表达量为360mg.L-1,占总蛋白含量的20%,与基础LB培养基相比,Krin-gle 5表达量提高了1.18倍。     

腈水解酶重组菌发酵产酶条件的优化及应用

优化了重组菌E.coli BL21(DE3)/pET28b(+)-NIT发酵产腈水解酶的条件,确定最适发酵培养基为:玉米浆粉25g.L-1,酵母浸出汁5g.L-1,NaCl 10g.L-1,Fe3+0.5mmol.L-1,初始pH值7.5;最适诱导产酶条件为:诱导剂乳糖0.5g.L-1,诱导剂加入时间为接种6h后,诱导温度30℃,诱导时间28h,在此条件下产酶量达到6161.46U.L-1。所得菌体用于不对称转化R,S-扁桃腈生成R-(-)-扁桃酸,转化率达92.02%,产物e.e.值达99%。     

肺炎克雷伯氏菌生物合成1,3-丙二醇的副产物调控研究

以肺炎克雷伯氏菌(Klebsiella pneumoniae)ATCC 25955为原始菌株,利用代谢工程手段对K.pneumoniae生物合成1,3-丙二醇(1,3-PD)的副产物进行调控.通过敲除副产物合成途径关键酶编码基因,在分批补料发酵条件下,1,3-PD的产量达到83.8 g·L-1,生产强度提至2.79 g·L-1·h-1;进一步结合乙酸吸收途径强化,有效解除了乙酸溢流现象,在分批补料发酵条件下,1,3-PD的产量达到94.9g·L-1,生产强度提至3.16 g·L-1·h-1.研究表明,通过敲除副产物合成途径关键酶编码基因结合乙酸吸收途径强化能够促进1,3-PD的合成,减少副产物的产生,提高K.pneu-moniae 代谢甘油合成1,3-PD的产量和生产强度.     

玉米浆对大肠杆菌JH-B22发酵产L-丙氨酸的影响

为了进一步降低L-丙氨酸的生产成本,以大肠杆菌JH-B22为发酵菌株,以玉米浆为氮源、葡萄糖结晶废糖液为碳源进行L-丙氨酸的发酵。结果表明,发酵培养基中玉米浆添加量为20g·L~(-1)较为适宜。在玉米浆发酵培养基中进行L-丙氨酸的发酵,L-丙氨酸产量和糖酸转化率分别为54.30g·L~(-1)和90.5%;其L-丙氨酸产量略低于无机盐发酵培养基的56.12g·L~(-1)和LB发酵培养基的56.48g·L~(-1),但玉米浆发酵培养基具有配制更简单、无需额外添加无机盐或者成本较高的酵母粉等优点,可作为L-丙氨酸发酵生产的不错选择。     

腈水解酶重组茵发酵产酶条件的优化及应用

摘要：优化了重组茵E．coliBL21（DE3）／pET28b（＋）-NIT发酵产腈水解酶的条件,确定最适发酵培养基为：玉米浆粉25g·L-1,酵母浸出汁5g·L-1,NaCl10g·L-1,Fe3＋0．5mmol·L-1。初始pH值7．5;最适诱导产酶条件为：诱导剂乳糖0．5g·L-1,诱导剂加入时间为接种6h后,诱导温度30℃,诱导时间28h,在此条件下产酶量达到6161．46U·L-1。所得茵体用于不对称转化R,S-扁桃腈生成R-（-）-扁桃酸,转化率达92．02％,产物e．e．值达99％。     

不同诱导剂对工程菌发酵及重组蛋白表达的影响

目的观察不同诱导剂对工程菌发酵及HSP-MUC1重组蛋白表达的影响,从而选取最佳诱导表达条件。方法分别用IPTG和乳糖作为诱导剂,发酵表达HSP-MUCI重组蛋白质,并对重组蛋白质表达量和性状进行分析。结果用IPTG诱导发酵的菌体经普通匀浆法即可将细菌破碎;而用乳糖发酵的菌体经普通匀浆法不能破菌,通过延长发酵时间也能达到与IPTG诱导相同的表达量。结论乳糖可以作为基因工程重组蛋白的理想诱导剂。     

谷氨酰转肽酶基因工程菌发酵条件优化的研究

对谷氨酰胺转肽酶基因工程菌进行活化发酵,探究建立最佳的发酵培养基组成成分,最大限度的提高该菌的产量从而提高谷氨酰胺转肽酶的产量。利用光密度大小与液体浑浊度有关对发酵培养基进行优化分析。实验结果表明,发酵培养基最优组分组成是:培养基含0.5%(w/v)的酵母浸粉和1%(w/v)的鱼粉蛋白胨作为氮源,0.5%(w/v)的乳糖作为碳源,0.5%(w/v)的氯化钠作为无机盐,优化后的培养基菌体光密度值大于优化前的发酵培养基菌体光密度值。     

恒定pH值对粘质沙雷氏菌产灵菌红素的影响

探讨了恒定pH值对粘质沙雷氏菌ZSG7发酵产灵菌红素的影响。结果表明,当发酵系统pH值恒定为7时,粘质沙雷氏菌生长速度最快,灵菌红素产生速度最快且产量最高(0.3033g·L-1),比不调pH值的灵菌红素最高产量0.2296g·L-1高出32.1%。     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、环氧树脂、不饱和聚酯树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍。