人分裂细胞核抗原基因片段的筛选、测序及对启动子的分析

经６．６×１０５个克隆筛选,从装在λ噬菌体载体Ｃｈａｒｏｎ３０中的人基因库中筛选到了一个含人分裂细胞核抗原（ＰＣＮＡ）基因的克隆。经Ｓｏｕｔｈｅｒｎ杂交分析插入基因长约１４ｋｂ,有较长的５＇上游区,但３＇端缺少一部分。经亚克隆和测序已确定从５＇上游１２６３ｂｐ到３＇端与λ载体接点共４９６９ｂｐＰＣＮＡ基因片段的核苷酸序列。将ＰＣＮＡ基因启动子核苷酸序列与ＤＮＡ聚合酶α,拓扑异构酶Ⅱα,胸苷酸激酶基因的启动子进行比较有３０％以上同源性,具有“看家基因”特征。在转录起始点的５＇上游几百ｂｐ的范围内都有与ＣＡＴ,ＳＰ１,Ｅ２Ｆ,ＮＦＨＢ,Ｏｃｔ１和ＡＴＦ等转录因子的结合位点相似的核苷酸序列。     

大豆籽粒蓝脐性状及其分离规律

控制大豆白花亲本籽粒脐色的基因有带Ｒ与ｒ之分,带Ｒ基因的白花产本与紫花亲本杂交,Ｆ１代籽料出现蓝脐性状,其基因型为Ｉ－Ｒ－Ｗ１－ｔｔ。当控制脐色的基因有两对相差时（Ｒ、ｒ;Ｗ１、ｗ１）Ｆ２代籽粒脐色分离蓝脐与无色脐之比为９∶７。     

Retinoic Acid Treatment Induces Cell Death and the Protein Expression of Retinoic Acid Receptor β in the Mesenchymal Cells of Mouse Facial Primordia in Vitro

We isolated mesenchymal cells from individual facial primordia of mouse embryos on 11 days post coitum and examined the effects of retinoic acid (RA) on chondrogenesis, induction of cell death, and the protein expression of retinoic acid receptor (RAR) β and γ in micromass culture. Under the control condition, cells of both medial and lateral nasal prominences (MNP and LNP) displayed high chondrogenic potential, while those of maxillary and mandibular prominences (Mx and Md) had constant growth activity and low chondrogenic potential. Though none of the cells expressed detectable levels of the RAR β protein, RAR γ was expressed in the cells of all the facial primordia. One μM RA inhibited the chondrogenesis, and induced cell death accompanied with the induction of the RAR β protein in LNP, MX and Md cells within 6 hr. On the contrary, both cell death and RAR β protein induction were detected in the MNP cells treated with RA for 24 hr. These results suggest that the RAR β is involved in the process of the cell death induced by the RA treatment in the mesenchymal cells of the mouse facial primordia.     

Phylogenetic relationships among eutherian orders estimated from inferred sequences of mitochondrial proteins: Instability of a tree based on a single gene

The phylogenetic relationships among Primates (human), Artiodactyla (cow), Cetacea (whale), Carnivora (seal), and Rodentia (mouse and rat) were estimated from the inferred amino acid sequences of the mitochondrial genomes using Marsupialia (opossum), Aves (chicken), and Amphibia (Xenopus) as an outgroup. The overall evidence of the maximum likelihood analysis suggests that Rodentia is an outgroup to the other four eutherian orders and that Cetacea and Artiodactyla form a clade with Carnivora as a sister taxon irrespective of the assumed model for amino acid substitutions. Although there remains an uncertainty concerning the relation among Artiodactyla, Cetacea, and Carnivora, the existence of a clade formed by these three orders and the outgroup status of Rodentia to the other eutherian orders seems to be firmly established. However, analyses of individual genes do not necessarily conform to this conclusion, and some of the genes reject the putatively correct tree with nearly 5% significance. Although this discrepancy can be due to convergent or parallel evolution in the specific genes, it was pointed out that, even without a particular reason, such a discrepancy can occur in 5% of the cases if the branching among the orders in question occurred within a short period. Due to uncertainty about the assumed model underlying the phylogenetic inference, this can occur even more frequently. This demonstrates the importance of analyzing enough sequences to avoid the danger of concluding an erroneous tree.     

Evidence that Prostaglandin E2 Can Block Calcium-Activated 86Rb Efflux from Rat Brain Synaptosomes via a Protein Kinase C-Dependent Mechanism

Abstract: The effects of prostaglandin E₂ (PGE₂) on ⁸⁶Rb efflux from rat brain synaptosomes were studied to explore its role in nerve ending potassium (K⁺) channel modulation. A selective dose-dependent inhibition of the calcium-activated charybdotoxin-sensitive component of efflux was found upon application of PGE₂. No significant effect was seen on basal and voltage-dependent components over the concentration range of 10–⁸ to 10–⁵M. The protein kinase C (PKC) inhibitors H-7 (10 μM) and staurosporine (100 nM), as well as prolonged preincubation (90 min) with 40-phorbol 12, 13-dibutyrate, which has been reported to down-regulate PKC, abolished the PGE₂-in- duced inhibition, whereas HA1004 (10 μM) and Rp-3′,5’cyclic phosphorothioate (100 nM), which are relatively more selective for protein kinase A than PKC, did not. 4β-Phorbol 12, 13-dibutyrate (100 nM), an activator of PKC, produced a similar inhibition of the Ca²⁺-dependent component of ⁸⁶Rb efflux but also had no effect on the basal and voltage-dependent components. These data suggest that PGE₂ can inhibit rat brain nerve ending calcium-activated ⁸⁶Rb efflux, and this inhibition may involve PKC activation.     

Effects of an antisense napin gene on seed storage compounds in transgenic Brassica napus seeds

To manipulate the quantity and quality of storage components in Brassica napus seeds, we have constructed an antisense gene for the storage protein napin. The antisense gene was driven by the 5-flanking region of the B. napus napin gene to express antisense RNA in a seed-specific manner. Seeds of transgenic plants with antisense genes often contained reduced amounts of napin. In some transgenic plants, no accumulation of napin was observed. However, the total protein content of transgenic and wild-type seeds did not differ significantly. Seeds lacking napin accumulated 1.4 to 1.5 times more cruciferin than untransformed seeds, although the oleosin content was not affected. Fatty acid content and composition in the seeds of transgenic plants were also analyzed by gas chromatography. Though the total fatty acid content of the transformants was the same as that of non-transformants, there was a reduction in 18:1 contents and a concomitant increase of 18:2 in seeds with reduced napin levels. This observed change in fatty acid composition was inherited in the next generation.     

Characteristics of Modified Leghemoglobins Isolated from Soybean (Glycine max Merr.) Root Nodules

Hemoprotein derivatives of an abundant soybean (Glycine max Merr.) root nodule leghemoglobin, Lba, were studied for their modified spectral characteristics and physical properties. Three modified hemoprotein derivatives of Lba (Lbam1, Lbam2, and Lbam3) were purified by preparative isoelectric focusing. The ferric forms of these pigments were green and exhibited anomalous spectra in the visible region as compared to the Lba3+ forms. These modified pigments showed a hypochromic shift of 10 nm for the charge transfer absorption maximum; however, differences were not apparent in the Soret region. Upon binding with nicotinate, the [alpha] and [beta] bands were shifted significantly into the red region as compared to the Lba3+ nicotinate complex. The three Lbam fractions were reduced by dithionite or by NADH in the presence of riboflavin. Lbam2+ also bound nicotinate and displayed absorption spectra indistinguishable from those of Lba2+ nicotinate. In contrast to Lba2+, Lbam2+ displayed aberrant spectra when bound with either O2 or CO. These complexes exhibited a prominent charge transfer band at approximately 620 nm and failed to exhibit spectra characteristic of Lba2+O2 and Lba2+CO. The protein moiety of these modified pigments was intact because their tyrosine/tryptophan ratios and their amino acid compositions were identical with those of Lba, nor were differences observed in the peptide profiles resulting from trypsin digests of purified Lba and Lbams. Automated Edman degradation of selected peaks further confirmed the intactness of the protein backbone including the absence of deamination. Pyridine hemochromogen for heme from Lbams could be formed, and the spectra displayed distinct differences compared to those of Lba. A new peak at 580 nm and a loss of a peak at 480 nm were observed for all three Lbams.     

中国盲走螨属一新种和二新纪录：蜱螨亚纲：植绥螨科

本文记述我国植绥螨科盲走螨属Ｔｙｐｈｌｏｄｒｏｍｕｓ一新种和中国二新纪录：鲁盲走螨Ｔ．ｌｕｅｎｓｉｓ ｓｐ．ｎｏｖ．,甲胄盲走螨Ｔ．ｌｏｒｃａｔｕｓ,肥厚盲走螨Ｔ．ｈｉｇｏｅｎｓｉｓ。标本保存于上海复旦大学环境和资源生物系。     

Mathematical models for the swimming pattern of a lamprey

A significant characteristic in a swimming pattern of a lamprey is the generation of a constant phase lag along its body in spite of the wide range of undulation frequencies. In this paper, we discuss a mathematical treatment for coupled oscillators with time-delayed interaction and propose a model for the central pattern generator (CPG) of a lamprey to account for the generation of a constant phase relation, with consideration of the signal conduction time. From this model, it is suggested that the desired phase relation can be produced by long ascending connections from the tail to the neck region of the CPG.     

Hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency: Identification of point mutations in Japanese patients with Lesch-Nyhan syndrome and hereditary gout and their permanent expression in an HPRT-deficient mouse cell line

Two different single nucleotide transitions of hypoxanthine-guanine phosphoribosyltransferase (HPRT) were identified in a Japanese patient with Lesch-Nyhan syndrome (LNS) and a patient with hereditary gout. HPRT enzyme activities in the two patients were severely deficient, but the size and amount of mRNA were normal according to Northern analysis. Entire coding regions of HPRT cDNAs were amplified by PCR and sequenced. A G-to-A substitution at base 208 in exon 3, which predicted glycine 70 to arginine, was detected in the LNS patient (identical mutation with HPRT_Utrecht). A C-to-A substitution at base 73 in exon 2, which predicted proline 25 to threonine, was detected in the gout patient (designated HPRT_Yonago). We transfected normal HPRT cDNA, mutant cDNA with HRPT_Utrecht or mutant cDNA with HPRT_Yonago, respectively, to HPRT-deficient mouse cells and isolated permanent expression cell lines. The HPRT-deficient mouse cells had no detectable HPRT activity and a very low amount of HPRT mRNA. When the HPRT-deficient mouse cells were transfected with normal human cDNA, HPRT enzyme activity increased to 21.8% that of normal mouse cells. The mouse cells transfected with HPRT_Utrecht showed no increase in HPRT activity; however, when the mouse cells were transfected with HPRT_Yonago, the activity increased to 2.4% that of normal activity. The proliferative phenotypes of these cells in HAT medium and in medium containing 6-thioguanine were similar to those of skin fibroblasts from the patients. This series of studies confirmed that each of the two point mutations was responsible for the decreases in HPRT enzyme activity, and the proliferative phenotypes in HAT medium and medium containing 6-thioguanine.