Increased shikonin production by hairy roots of Lithospermum erythrorhizon in two phase bubble column reactor

Summary Plant hairy root cultures of Lithospermum erythrorhizon were carried out to produce shikonin derivatives by employing in situ extraction with n-hexadecane in a shake flask and a bubble column bioreactor. Over 95 % shikonin produced was recovered in the n-hexadecane layer. In flask cultures the maximum concentration of shikonin with n-hexadecane extraction was 3 times higher than that obtained without extraction. In the two phase bubble column reactor, 572.6 mg/L of shikonin and 15.6 g/L of dry cell mass were obtained after 54 days. Shikonin was produced at a constant level of 10.6 mg/L day during this period.     

钙／钙调素依赖性蛋白激酶对17．7kD和6kD胰腺蛋白的磷酸化

本文报导了胰腺提取物中两种可被钙／钙调素依赖性蛋白激酶磷酸化的热稳定蛋白。ＳＤＳ－ＰＡＧＥ测定其表观分子量分别为１７．７ｋＤ和６ｋＤ。经钙／钙调素依赖性蛋白激酶磷酸化后,其最大磷酸参入量为８．８μｍｏｌ／ｇ蛋白。同时磷酸化作用导致１７．７ｋＤ蛋白在ＳＤＳ－ＰＡＧＥ中迁移率发生变化。本文还进一步分析了各种阳离子对磷酸化的影响,并对此两种蛋白可能具有的生理功能进行了初步探讨。     

A NEW SPECIES OF GENUS HABROPHLEBIODES ULMER (EPHEMEROPTERA: LEPTOPHLEBIIDAE)

Abstract  The present paper deals with a new species Habrophlebiodes zijinensis sp. nov. collected in Nanjing, Jiangsu Povince, China.     

A spin label study of immobilized enzyme spectral subpopulations

Electron spin resonance (ESR) spin label studies have been carried out to examine the active site conformation of alpha-chymotrypsin before and after immobilization on two types of organic polymer supports: Amberlite XAD-8 and XAD-2. alpha-Chymotryspin was first chemically modified by reaction with methyl-4-phenylbutyrimidate and then inhibited by the active site spin label 4-(2,2,6,6-tetramethyl-piperdine-1-oxyl)-m-flurosulfonylbenzamide. In general, the ESR spectra of the active site lable revealed no significant changes in conformation for most of the enzyme before or after derivatization. On the other hand, two spectral subpopulations (A and B) of spin-labeled enzyme were characterized on the basis of their ESR spectra after immobilization on Amberlite XAD-8. Spectral subpopulation A (distinguished by a highly restrained spectrum) appeared to retain its active site structure and conformation and represented a large majority of the labeled chymotrypsin on the beads. Its presence correlated with the high activity and stability of phenylbutyramidinated chymotryspin on the Amberlite XAD-8 beads. Spectral subpopulation B (distinguished by a very weakly constrained spectrum) appeared to reflect loosely bound or denatured enzyme which was removable upon washing with 40% (v/v) ethylene glycol. Two methods for examining solvent accessibility to the active site lable of the kinetics of ascorbate reduction suggested that both spectral subpopulations had identical accessibilities to the bulk solvent. Paramagnetic broadening of the signal by K(3)Fe(CN)(6) revealed differences in the spin-spin broadening of the A and B components but is deemed and inappropriate indicator of solvent accessibility.     

Alteration of mitochondrial genomes containing atpA genes in the sexual progeny of cybrids between Raphanus sativus cms line and Brassica napus cv. Westar

Summary We have investigated the fate of the mitochondrial genomes of cybrids derived from donor-recipient protoplast fusion between X-irradiated Raphanus sativus (cms line) and iodoacetamide-treated Brassica napus cv. Westar. Two out of ten fusion products were male-sterile with the diploid chromosome number of B. napus. The mitochondrial (mt) genomes of the cybrids and their progeny were further analyzed by DNA-DNA hybridizaion using the pea mitochondrial ATPase subunit gene (atpA) as a probe. One cybrid, 18-3, had a 3.0 kb fragment characteristic of B. napus and a 2.0 kb non-parental fragment when the BamHI-digested DNA was hybridized with the probe. In the first-backcrossed progeny of this cybrid, the hybridization pattern was not stably inherited. A 4.0 kb radish fragment, not detectable in the cybrid, appeared in one of the BC₁ generation siblings, and the 2.0 kb non-parental fragment was lost in another. The hybridization patterns in BC₁ progeny siblings of cybrid 12-9 were also varied. The alteration of mtDNA in the cybrid progeny continued to the BC₂ generation. There was no clear evidence of a heteroplasmic state or of sub-stoichiometric molecules in the mt genome of cybrid 18-3. A possible cause of the observed alteration in the mt genome is discussed.     

Identification of new urinary metabolites of trimeprazine in rats by gas chromatography—mass spectrometry

The metabolites of trimeprazine were identified in urine of rats by gas chromatography—mass spectrometry. After the oral administration of trimeprazine, the urinary metabolites were extracted with diethyl ether before or after hydrolysis with β-glucuronidase. The identified metabolites were N-demethyltrimeprazine, 3-hydroxytrimeprazine, N-demethyl-3-hydroxytrimeprazine and trimeprazine sulphoxide.     

A preliminary X-ray study of a refolded PTS EIIBfruc protein from Escherichia coli

The phosphoenolpyruvate-carbohydrate phosphotransferase system (PTS) catalyzes the phosphorylation and transportation of its sugar substrates. A sugar-specific enzyme II complex involved in the PTS finally functions to translocate substrates across the membrane. A PTS EIIB(fruc) protein, a fructose specific EIIB subunit, from Escherichia coli has been cloned, expressed, refolded, purified, and crystallized. The synchrotron data were collected to 2.6 A from the crystal of a selenomethionine substitute PTS EIIB(fruc) protein. The crystal belongs to the primitive trigonal space group P3(1)21, with unit-cell parameters of a = 33.4 A, b = 33.4 A, c = 154.0 A, and beta = 120.0 degrees . A full structure determination is under way to provide insights into the structure-function relationships of this protein.     

Methylation protects miRNAs and siRNAs from a 3'-end uridylation activity in Arabidopsis

Small RNAs of 21-25 nucleotides (nt), including small interfering RNAs (siRNAs) and microRNAs (miRNAs), act as guide RNAs to silence target-gene expression in a sequence-specific manner. In addition to a Dicer homolog, DCL1, the biogenesis of miRNAs in Arabidopsis requires another protein, HEN1. miRNAs are reduced in abundance and increased in size in hen1 mutants. We found that HEN1 is a miRNA methyltransferase that adds a methyl group to the 3'-most nucleotide of miRNAs, but the role of miRNA methylation was unknown. Here, we show that siRNAs from sense transgenes, hairpin transgenes, and transposons or repeat sequences, as well as a new class of siRNAs known as trans-acting siRNAs, are also methylated in vivo by HEN1. In addition, we show that the size increase of small RNAs in the hen1-1 mutant is due to the addition of one to five U residues to the 3' ends of the small RNAs. Therefore, a novel uridylation activity targets the 3' ends of unmethylated miRNAs and siRNAs in hen1 mutants. We conclude that 3'-end methylation is a common step in miRNA and siRNA metabolism and likely protects the 3' ends of the small RNAs from the uridylation activity.     

PLZF-RARα融合基因的生物学功能研究

构建了8个PLZF-RARα融合基因突变体.用“滞后”胶实验证实PLZF-RARα与PML-RARα一样,亦能以同二聚体的形式结合到维甲酸反应元件(RARE)上,且PLZF的POZ结构域介导PLZF-RARα同二聚体的形成和稳定.但两者与RARE的结合类型存在差异,在DR5G,PML-RARα的结合强度大于PLZF-RARα;而在DR5T,则是PLZF-RARα强于PML-RARα.进一步工作证实PLZF-RARα能与RXR形成异二聚体,并产生4种复合物.用免疫沉淀法发现PLZF-RARα亦能与PLZF形成异二聚体,而且也是通过POZ结构域介导PLZF-RARα和PLZF异二聚体的形成.同PML-RARα一样,PLZF-RARα对RARE的结合反应亦受维甲酸调控.     

鲍肽素对血管性痴呆大鼠学习与记忆能力的干预及机制研究

目的：观察鲍肤索对血管性痴呆大鼠学习与记忆能力的干预及机制。方法：制备生物鲍肤索,分剂量喂饲血管性痴呆大鼠,测试学习与记忆能力、红细胞和血红蛋白。结果：鲍肤素提高大鼠Y型迷宫测试的分值和红细胞、血红蛋白水平。结论：鲍肤素能提高血管性痴呆大鼠的学习与记忆能力和红细胞、血红蛋白水平。