Protein loading,elution, and resolution behavior in a novel device that integrates ultrafiltration and chromatographic separation

Hollow fiber membranes and chromatographic resin beads are commonly employed in a variety of bioseparation processes. A new class of integrated separation devices is being studied in which the shell side of a hollow fiber device is filled with adsorbents/chromatographic resin beads. Such devices and the corresponding separation methods integrate feed broth clarification by the microfiltration/ultrafiltration membrane with bioproduct purification by the shell-side resin beads either as an adsorbent or as beads in elution chromatography. A mathematical model has been developed for the prediction of the chromatographic behavior of such an integrated device. Simulations have been done to study the effects of axial dispersion, feed flow rate, water permeation rate, fiber packing density, and void fraction. Numerical solutions were obtained by solving the governing equations. This model can reasonably describe the concentration profiles as well as the breakthrough and elution behaviors in the integrated device.     

Toward the Synthesis of Pyroglutamate Lauroyl Ester: Biocatalysis Versus Chemical Catalysis

The synthesis of dodecyl pyroglutamate (or pyroglutamate lauroyl ester) was achieved in a two-step process involving a pyroglutamic acid alkyl ester intermediate. The reaction was carried out either by lipase or by chemical catalysis using ion exchange resin. Among the various tested lipases, the one from Candida antarctica B gave the best results allowing 73% formation of the desired ester after 6 h. Comparing the efficiency of this latter lipase with the one of Amberlyst IR120H resin in catalyzing this reaction, the biocatalyst gave a molar yield of pyroglutamate lauroyl ester of 79% compared to 69% when using the ion exchange resin starting with 1.04 mmol substrate in each case.     

“增温溶解,保温过柱,温水解吸“提制二氢杨梅素(一)

采用“增温溶解 ,保温过柱 ,温水解吸”的方法对显齿蛇葡萄中的二氢杨梅素进行提制研究。结果表明 :该方法的适宜温度为 5 0～ 70℃ ,最好为 6 0℃ ,方法能很好地将 70 %左右的二氢杨梅素提纯到80 % ;提纯二氢杨梅素时 ,单位数量的D 16大孔吸附树脂处理料液的数量 ,主要取决于料液中二氢杨梅素的纯度。     

The effect of water status and season on the incorporation of 14CO2 and [14C]-acetate into resin and rubber fractions in guayule

The effects of drought stress and season on both allocation of photosynthates to stems and leaves and potential for stem rubber synthesis were studied in guayule ( Parthenium argentatum Gray USDA line 11604). Two-year-old plants grown under field conditions in the Negev desert of Israel were subjected to different irrigation regimes, and water status was assessed by measuring the relative water content (RWC). Undetached plant tips were exposed to a 1 h pulse of ¹⁴CO₂, followed by a 24 h chase. ¹⁴C fixed and translocated to different plants parts and notably ¹⁴C incorporation into rubber and resin fractions was determined. The potential of detached branch slices to incorporate [¹⁴C]-acetate into rubber was also studied. A higher percentage of fixed ¹⁴C was translocated from shoot tips in winter (28–30%) than in summer (15–18%). The percentage of [¹⁴C]-acctate incorporated into the rubber fraction by stem slices was maximal in winter (20%) and minimal in summer (3–5%) in both cases in the absence of drought stress. In summer the translocation of photosynthates into stems was inversely related to plant RWC, dropping from 18% three days after irrigation to 3% 14 days later, and the potential of stems to synthesise rubber was high under drought conditions and low in well irrigated plants.     

壳菜果植物树脂道的发生、发育及分布的研究

经解剖观察,发现壳菜果（Ｍｙｔｉｌａｒｉａｌａｏｅｎｓｉｓ）植物初生结构能自然形成树脂道,而次生结构不能自然形成。树脂道原始细胞发生位置为离顶端１２０～１４０μｍ的区段上,与初生分生组织同时形成。以后原始细胞经历;（１）原始细胞分裂阶段;（２）树脂道发生阶段;（３）树脂道扩张阶段;（４）树脂道成熟阶段;（５）树脂道破毁阶段而完成其功能周期。壳菜果植物的树脂道以裂溶生方式发生,分布在维管束外侧的皮层中。此为金缕梅科各亚科系统位置研究提供重要证据     

大孔NH_4~+型阳离子交换树脂离子交换法提取谷氨酸的研究

采用四种大孔ＮＨ＋４型阳离子交换树脂Ｄ００１、Ｄ６１、Ｄ７２、Ｄ１１３从等电点结晶母液中回收谷氨酸,其中Ｄ６１树脂取得了良好的交换效果。Ｄ６１树脂吸附谷氨酸的离子交换等温线可以用Ｆｒｅｕｎｄｌｉｃｈ方程表示ｑ＝５．３３９（Ｃ＊）０．４４７８。将Ｄ６１树脂上柱交换,测出了不同空间流速下的穿透曲线,得到了适宜的流速为２．１６ｍｌ／ｍｌ．ｈ。     

The effect of cerulenin on the production of esperamicin A1 byActinomadura verrucosospora

Summary Addition of cerulenin (0.25–1.0 mM) to cultures ofActinomadura verrucosospora before the onset of esperamicin synthesis inhibited the production of esperamicin A₁ by the microorganism. This result indicates that esperamicin A₁ is biosynthesized in part by the polyketide pathway. Addition of cerulenin to the cultures during the active production phase led to a net decrease in esperamicin A₁ production. The¹⁴C-acetate labeling pattern of esperamicin A₁ in the cultures with or without addition of cerulenin at the active production phase also demonstrated the instability of esperamicin A₁ in the fermentation. This suggests that esperamicin A₁ is unstable and degradation occurs during the active production phase. Addition of the neutral resin Diaion HP-20 (1%) to the fermentation enhanced the production of esperamicin A₁ by 53%.     

Re-dating the Early Upper Paleolithic Levels of Le Trou Magrite (Pont-à-Lesse,Belgium)

All but one of the published radiocarbon dates from the 1991–1992 excavations of Strata 3 and 2 at le Trou Magrite are considered too recent because the dating was done with then-standard chemical pretreatment protocols. This study re-dates Stratum 2 using the same, then-pioneering, XAD-2 purification method on bone collagen as had been used for the 44,650 cal BP date from Stratum 3. The results are two averaged dates that are in stratigraphic order between themselves and in relation to the Stratum 3 date: 43,400 and 43,500 cal BP, according to the IntCal20 curve. These dates are very similar to recently published dates for the earliest Aurignacian in SW Germany and the latest Neanderthal remains in Belgium and they are associated with artifact assemblages that, without obvious evidence of mixture (other than that which was highly localized), include Upper Paleolithic stone tools and blades/bladelets together with numerous sidescrapers, denticulates and notches which are not exclusively Mousterian artifacts. Nineteenth-century excavations in the cave of le Trou Magrite yielded unambiguously diagnostic Aurignacian artifacts and works of portable art that could conceivably have been from a deposit equivalent in age to these strata on the contiguous terrace. It is clear that the first blade(let)-rich assemblages in the site were created on the cusp of the transition from the Middle-to-Upper Paleolithic transition and replacement of the Neanderthals in NW Europe.     

The accumulation and distribution of trace metals in some localized marine species

Trace elements, such as As, Co, Cr, Hg, Sb, and Zn, were determined by neutron activation analysis (NAA), whereas Cd, Cu, and Pb were determined by graphite furnace atomic absorption spectroscopy (GFAAS) in clam, crab, prawn, swamp cerith, and mussel samples after digestion by microwave heating under controlled conditions before eluting the solutions through a column of a chelating resin, Chelex-100. The standard used in the determination of percentage volatile elements retained by microwave digestion and also in the activation process wasLobster Hepatopancreas TORT-1, whereas known mixed standards were prepared from nitrate salts to determine the efficiency of the separation procedure at a controlled pH. Mercury and lead detected in crabs exceeded the maximum permissible level. Some species also showed a high affinity toward certain elements, and their levels of accumulation in the tissues of these species corresponded with the concentration of these elements in sediments, especially at sites in the vicinity of an industrial zone.