N-Linked glycosylation of a baculovirus-expressed recombinant glycoprotein in insect larvae and tissue culture cells

The potential of insect cell cultures and larvae infected with recombinant baculoviruses to produce authentic recombinant glycoproteins cloned from mammalian sources was investigated. A comparison was made of the N-linked glycans attached to secreted alkaline phosphatase (SEAP) produced in four species of insect larvae and their derived cell lines plus one additional insect cell line and larvae of one additional species. These data survey N-linked oligosaccharides produced in four families and six genera of the order Lepidoptera. Recombinant SEAP expressed by recombinant isolates of Autographa californica and Bombyx mori nucleopolyhedroviruses was purified from cell culture medium, larval hemolymph or larval homogenates by phosphate affinity chromatography. The N-linked oligosaccharides were released with PNGase-F, labeled with 8- aminonaphthalene-1-3-6-trisulfonic acid, fractionated by polyacrylamide gel electrophoresis, and analyzed by fluorescence imaging. The oligosaccharide structures were confirmed with exoglycosidase digestions. Recombinant SEAP produced in cell lines of Lymantria dispar (IPLB-LdEIta), Heliothis virescens (IPLB-HvT1), and Bombyx mori (BmN) and larvae of Spodoptera frugiperda, Trichoplusia ni , H.virescens , B.mori , and Danaus plexippus contained oligosaccharides that were structurally identical to the 10 oligosaccharides attached to SEAP produced in T.ni cell lines. The oligosaccharide structures were all mannose-terminated. Structures containing two or three mannose residues, with and without core fucosylation, constituted more than 75% of the oligosaccharides from the cell culture and larval samples.      

Unusual pattern of bacterial ice nucleation gene evolution

Bacterial ice nucleation activity (INA+ phenotype) can be traced to the product of a single gene, ina. A remarkably sparse distribution of this phenotype within three bacterial genera indicates that the ina gene may have followed an unusual evolutionary path. Southern blot analyses, coupled with assays for ice-nucleating ability, revealed that within four bacterial species an ina gene is present in some strains but absent from others. Results of hybridization experiments using DNA fragments that flank the ina gene suggested that the genotypic dimorphism of ina may be anomalous. A phylogenetic analysis of 16S ribosomal RNA gene sequences from a total of 14 ina+ and ina- bacterial strains indicated that the ina+ bacteria are not monophyletic but instead phylogenetically interspersed among ina- bacteria. The relationships of ina+ bacteria inferred from ina sequence did not coincide with those inferred from the 16S data. These results suggest the possibility of horizontal transfer in the evolution of bacterial ina genes.      

Rates and equilibria at the acetylcholine receptor of electrophorus electroplaques. A study of neurally evoked postsynaptic currents and of voltage-jump relaxations

Kinetic measurements are employed to reconstruct the steady-state activation of acetylcholine [Ach] receptor channels in electrophorus electroplaques. Neurally evoked postsynaptic currents (PSCs) decay exponentially; at 15 degrees C the rate constant, α, equals 1.2 ms(-1) at 0 mV and decreases e-fold for every 86 mV as the membrane voltage is made more negative. Voltage-jump relaxations have been measured with bath-applied ACh, decamethonium, carbachol, or suberylcholine. We interpret the reciprocal relaxation time 1/τ as the sum of the rate constant α for channel closing and a first-order rate constant for channel opening. Where measureable, the opening rate increases linearly with [agonist] and does not vary with voltage. The voltage sensitivity of small steady-state conductances (e- fold for 86 mV) equals that of the closing rate α, confirming that the opening rate has little or no additional voltage sensitivity. Exposure to α-bungarotoxin irreversibly decreases the agonist-induced conductance but does not affect the relaxation kinetics. Tubocurarine reversibly reduces both the conductance and the opening rate. In the simultaneous presence of two agonist species, voltage-jump relaxations have at least two exponential components. The data are fit by a model in which (a) the channel opens as the receptor binds the second in a sequence of two agonist molecules, with a forward rate constant to 10(7) to 2x10(8) M(-1)s(-1); and (b) the channel then closes as either agonist molecule dissociates, with a voltage-dependent rate constant of 10(2) to 3x10(3)s(-1).     

ERRATUM: New Body Mass Estimates for Omomys carteri,a Middle Eocene Primate From North America. Am J Phys Anthropol 109:41–52.

Payseur BA, Covert HA, Vinyard CJ, Dagosto M. 1999. New Body Mass Estimates for Omomys carteri, a Middle Eocene Primate From North America. Am J Phys Anthropol 109:41–52. This article included an incomplete Table 2. The final two columns, showing “Intercept” and “SEE” data were omitted. The complete Table 2, with these two columns included, is provided below.     

AROMA PROPERTIES AND THRESHOLDS OF SOME BRANCHED-CHAIN AND OTHER MINOR VOLATILE FATTY ACIDS OCCURRING IN MILKFAT AND MEAT LIPIDS1

Aroma properties of twenty-three branched-chain, odd-numbered, or unsaturated fatty acids which had each been dispersed in acidic aqueous media (pH 2.0) were evaluated. Aroma threshold values were determined using approximately 95 judges for assessing the presence of aromas over dilutions of each fatty acid. Qualitative aroma threshold values for individual fatty acids ranged from 0.006 to 82.4 ppm in the acidic solutions, and 4-ethyloctanoic acid exhibited the lowest threshold of the group tested. Qualitative aroma assessments of dilutions of each fatty acid showed a wide range of unique aroma properties. Fatty acids exhibiting branching at the 4-position had goaty/muttony/sheepy aroma notes as did other fatty acids containing 8-carbon chain structures. Cheese-like aromas were associated with the shorter branched-chain fatty acids.     

新体系下茴脑臭氧化反应制取茴香醛(英文)

以茴脑为原料,乙酸乙酯和水为新型混合溶剂,室温下通过臭氧化分解反应制取茴香醛,并对比了该体系下和传统溶剂体系下茴香醛产率的差别。实验考察了溶剂种类、溶剂用量、臭氧气流量、混合溶剂中水含量和反应时间等工艺参数,并通过红外光谱和紫外分光光度计对反应机理进行了探讨验证。该反应在水的存在下实现了室温下一锅法合成茴香醛,产率可达81.7%,避免了茴脑臭氧化物的分离及还原步骤,工艺简单,洁净环保。     

喀斯特断陷盆地区不同恢复阶段群落物种组成与多样性特征

研究自然植被恢复过程中的物种组成、群落结构及生物多样性的变化,能够为人工促进植被恢复的树种选择与群落结构的优化配置提供重要依据。本研究以空间代替时间对喀斯特断陷盆地典型区云南省建水县不同天然植被(草丛、灌丛、乔木林)进行群落学调查,对不同恢复阶段的植物群落按乔木、灌木、草本进行分层,分析各恢复阶段植物群落的物种组成、水平和垂直结构、生物多样性。结果表明:在总面积为3200 m^2的12个样地中,共记录43科72属94种维管束植物,优势种以壳斗科(Fagaceae)、鼠李科(Rhamnaceae)、紫金牛科(Myrsinaceae)、蔷薇科(Rosaceae)、木犀科(Oleaceae)等科的植物为主;在草丛→灌丛→乔木林的恢复过程中,群落物种组成中的科数、属数、种数逐渐增加,低矮和小径级植物个体数所占比例逐渐减少,但整体仍以低矮的小径级植物为主。草本植物的丰富度和Shannon指数在植被恢复的初期即草丛阶段最大,而均匀度指数则以灌丛阶段最大;木本植物的丰富度和Shannon指数随着植被的恢复逐渐增大,但均匀度指数随着植被的恢复逐渐下降;随着植被的恢复,草本层和乔木层的生态优势度逐渐增大,灌木层的生态优势度逐渐减小;草本植物由早期一年或多年生的喜阳、耐旱、耐贫瘠的草本向抗逆性强的多年生草本过渡,并逐渐向中性和阴性转变,其中刺芒野古草(Arundinella setosa)能够很好地适应该地区的环境;薄叶鼠李(Rhamnus leptophylla)、铁仔(Myrsine africana)、假虎刺(Carissa spinarum)、小石积(Osteomeles anthyllidifolia)等阳性树种为该地区植被恢复的先锋种,其早期的出现为其他植物的恢复创造条件,后期又逐渐被喜阴的植物替代,在植被恢复初期可利用这些物种;在植被恢复后期,壳斗科的铁橡栎(Quercus cocciferoides)成为建群种,可在灌丛阶段植被恢复时利用该物种,也可以选择使用该物种植树造林;在整个植被恢复过程中,优势度从以矮小植物为主朝着高大植物发展、优势种寿命越来越长的趋势十分明显。     

携带IL-2/NK4双基因减毒沙门氏菌TPIN的遗传稳定性研究

对携带IL-2/NK4双基因减毒沙门氏菌TPIN的遗传稳定性进行研究。将TPIN连续传40代,取10代、20代、30代、40代菌落进行鉴定,包括菌落和菌体的形态、质粒的纯度和浓度、目的基因片段、双酶切结果及转染人肝癌细胞(HepG2)后目的基因体外表达活性。结果表明,每10代的菌落和菌体形态一致,其所含质粒的纯度和浓度在传代过程中无明显变化,PCR扩增的目的基因条带大小一致,双酶切鉴定结果正确,转染HepG2细胞后,每代间所表达目的蛋白浓度无明显差异。TPIN作为消化道肿瘤的生物治疗药物,在遗传方面有较好的稳定性,可进一步进行大量生产。     

热休克蛋白70在原发性高血压中的表达及其与炎症因子和血压的关系

目的:探讨原发性高血压患者热休克蛋白70(HSP-70)的表达水平,并分析其与炎症因子、血压的关系。方法:选择2017年3月至2019年3月我院收治的原发性高血压患者84例作为研究组,根据患者血压水平分为Ⅰ级组25例,Ⅱ级组37例和Ⅲ级组22例,另选同期体检健康者60例作为对照组,应用逆转录聚合酶链式反应(RT-PCR)检测各组血HSP70 m RNA水平,应用双抗体酶联免疫吸附法检测各组血清HSP-70、白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)和C反应蛋白(CRP)水平,比较各组血HSP70 m RNA、血清HSP70、IL-6、TNF-α和CRP水平,并分析相关性。结果:研究组血HSP-70mRNA相对表达量高于对照组(P0.05)。随高血压分级的升高各组患者血HSP-70mRNA相对表达量呈升高趋势,各组血HSP-70mRNA水平比较有统计学差异(P0.05)。研究组血清HSP-70、IL-6、TNF-α和CRP水平均高于对照组(P0.05)。随高血压分级的升高,各组患者血清HSP-70、IL-6、TNF-α和CRP水平呈升高趋势,不同组别血清HSP-70、IL-6、TNF-α和CRP水平比较有统计学差异(P0.05)。经Pearson相关分析显示,高血压患者血HSP-70 m RNA、HSP-70、IL-6、TNF-α和CRP水平与血压呈正相关(P0.05),血HSP-70 m RNA与IL-6、TNF-α和CRP水平呈正相关(P0.05),血清HSP-70与IL-6、TNF-α和CRP呈正相关(P0.05)。结论:高血压患者HSP-70和炎症因子异常升高,HSP-70与炎症因子水平和血压相关,提示HSP-70在高血压发生、发展中起到关键作用。