REVIEWS

B ehavioral B iology of K iller W hales . Barbara C. Kirkevold and Joan S. Lockard, eds.
A rctic W halers , I cy S eas . N arratives of the D avis S trait W hale F ishery . W. Gillies Ross.
B ibliographie Ü ber W al -B ibliographie . C etacea . B ibliography on W hale -B ibliographies . Franz W. Bekierz.
R ight W hales : P ast and P resent S tatus . P roceedings of the W orkshop on the S tatus of R ight W hales . Robert L. Brownell, Jr., Peter B. Best and John H. Prescott (eds.).
O rdering the O ceans . Clyde Sanger.     

Novelities of Asteraceae

Seven new taxa, including one new section, three new species and three new varieties, are described; one new name, Ligularia pojarkovana S. W. Liu et T. N. Ho, and one new combination, Ligularia liatroides (C. Winkl.) Hand.-Mazz. var. shifangensis (G. H. Chen et W. J. Zhang) S. W. Liu et T. N. Ho are made; five species are mentioned as new records. The seven new taxa are Youngia sect. Cyanoglossa S. W. Liu et T. N. Ho, Youngia zhenduoi S. W. Liu et T. N. Ho, Y. cyanea S. W. Liu et T. N. Ho, Mulgedium qinghaicum S. W. Liu et T. N. Ho, Cremanthodium campanulatum (Franch.) Diels var. flavidum S. W. Liu et T. N. Ho, Ligularia amplexicaulis DC. var. nepalensis S. W. Liu et T. N. Ho, and L. paradoxa Hand. Mazz. var.palmatifida S. W. Liu et T. N. Ho.     

菊科新资料

记述了菊科6个属的一些新分类群和新分布,包含1个新组、3个新种、3个新变种、1个新名称、1个新组合和5个种的新记录。这些新分类群是黄鹌菜属蓝舌组、振铎黄鹌菜、蓝花黄鹌菜、青海乳苣、黄苞垂头菊、尼泊尔橐吾和半裂橐吾。     

Both yeast W double-stranded RNA and its single-stranded form 20S RNA are linear.

Most yeast strains carry a cytoplasmic double-stranded RNA (dsRNA) molecule called W, of 2.5 kb in size. We have cloned and sequenced most of W genome (1), and we proposed that W (+) strands were identical to 20S RNA, a single-stranded RNA (ssRNA) species, whose copy number is highly induced under stress conditions. Recently it was proposed that 20S RNA was circular (2). In this paper, however, we demonstrate that both W dsRNA and 20S RNA are linear. Linearity of W dsRNA is shown by the stoichiometric labelling of both strands of W with 32P-pCp and T4 RNA ligase. The last 3' end nucleotide of both strands is about 70 to 80% C and 20 to 30% A. Linearity of 20S RNA is directly demonstrated by a site-specific cleavage of 20S RNA with RNase H, using an oligodeoxynucleotide complementary to an internal site of 20S RNA. The cleavage produced not one but two RNA fragments expected from the linearity of 20S RNA.     

Book reviews

THE BIOLOGY OF MOSSES. by D. H. S. R ichardson
PRINCIPLES OF GENETIC MANIPULATION: AN INTRODUCTION TO GENETIC ENGINEERING . By R. W. O ld & S. B. P rimrose Second Edition
HANDBOOK OF PLANT VIRUS INFECTIONS: COMPARATIVE DIAGNOSIS . Edited by E douard K urstak .
CYTOGENETICS . By J urgen S chulz -S chaeffer
PLANT SCIENCE: AN INTRODUCTION TO WORLD CROPS . By J. J anick , R. W. S chery , F. W. W oods , & V. W. R uttan     

Long-term salt loading impairs pituitary responsiveness to ACTH secretagogues and stress in rats

Male Wistar rats were allowed to drink tap water ad lib (W), 2% saline (S) or 2% saline containing dexamethasone (S + D, 1 mg/l) for 7 days. On the 8th day rats were subjected to a 3-min ether stress. Plasma ACTH, corticosterone and prolactin concentrations were determined before and after ether exposure. Prestress concentrations of plasma ACTH were low and did not vary among the three groups. In response to ether stress W rats exhibited twice as high plasma ACTH concentrations as did S rats. Rats of the S + D group exhibited a small but statistically significant ACTH response. Plasma corticosterone concentration in S rats was increased while in S + D rats was significantly decreased under resting conditions compared to that in W rats. Ether stress caused large increases in plasma corticosterone concentrations in W and S rats while a small but statistically significant increase was observed in S + D rats. Prolactin responses to ether were smaller in groups S and S + D than in group W. To test whether the decreased ACTH response to ether exposure was a result of a decreased sensitivity of corticotrope cells to corticotropin releasing factor (CRF)-41 or arginine vasopressin (AVP), adenohypophysial fragments from W, S and S + D rats were incubated in the presence of different doses of CRF-41 or AVP. Pituitary fragments obtained from W rats secreted larger amounts of ACTH than did pituitaries from S rats in response to either CRF-41 or AVP.(ABSTRACT TRUNCATED AT 250 WORDS)     

Books

Book reviews in this article:
C ommunication and B ehavior of W hales . R. Payne (ed.).
S trandings : W ays T o S ave W hales . F. D. r obson .
O rders and F amilies of R ecent M ammals of T he W orld . S. Anderson and J. Knox Jones, Jr. (eds.).
S oviet -A merican C ooperative R esearch on M arine M ammals . V olume l—P innipeds . F. H. Fay and G. A. Fedoseev (eds.).
P athobiology of M arine M ammal D iseases . E. B. Howard (ed.).
S eals of T he W orld . (Second Edition.) J. E. Ring. British Museum and Cornell University Press.
T he G ray W hale : E schrichtius R obustus . M. L. Jones, S. L. Swartt and S. Leatherwood.
T he S ierra C lub H andbook of W hales and D olphins . S. Leatherwood and R. R. Reeves.     

REVIEWS

Tobacco Diseases and Decays. By F. A. W olf
Diseases of Vegetable Crops. By J. C. W alker
Bacterial Plant Diseases. By A. J aczewski
The Cultivated Races of Sorghum. By J. D. S nowden
Protoplasm. By W. S eifriz
Evolution. By A. F ranklin S hull
Sea Trout and Trout. By W. J. M. M enzies     

国产海桑属植物的两个杂交种

作者通过对红树林海桑属植物进行形态学、花粉学、细胞学以及其它方面的比较研究,证实了拟海桑和海南海桑为两个杂交种,它们的嫌疑亲本分别是杯萼海桑和海桑、杯萼海桑和卵叶海桑·ｓｏｎｎｅｒａｔｉａ×ｈａｉｎａｎｅｎｗｓｉｓｋｏ,ＥＹ．ＣｈｅｎｅｔＷ．Y　Ｃｈｅｎ（ｐｒｏｓｐ）为海南海桑的新名称,而拟海桑S．ｐａｒａｃｓｅｏｌａｒｉｓＫｏ,Ｅ.Ｙ.Ｃｈｅｎ,ｅｔＷ,ＣｈｅｎＹ.Ｃｈｅｎ则被归并入ｓｏｎｎｅｒａｔｉａ×ｇｕｌｎｇａｉＮ.C．Ｄｕｋｅ．     

A soluble form of fibroblast growth factor receptor 2 (FGFR2) with S252W mutation acts as an efficient inhibitor for the enhanced osteoblastic differentiation caused by FGFR2 activation in Apert syndrome

Apert syndrome is an autosomal dominant disease characterized by craniosynostosis and bony syndactyly associated with point mutations (S252W and P253R) in the fibroblast growth factor receptor (FGFR) 2 that cause FGFR2 activation. Here we investigated the role of the S252W mutation of FGFR2 on osteoblastic differentiation. Osteoblastic cells derived from digital bone in two Apert patients with the S252W mutation showed more prominent alkaline phosphatase activity, osteocalcin and osteopontin mRNA expression, and mineralized nodule formation compared with the control osteoblastic cells derived from two independent non-syndromic polydactyly patients. Stable clones of the human MG63 osteosarcoma cells (MG63-Ap and MG63-IIIc) overexpressing a splice variant form of FGFR2 with or without the S252W mutation (FGFR2IIIcS252W and FGFR2IIIc) showed a higher RUNX2 mRNA expression than parental MG63 cells. Furthermore MG63-Ap exhibited a higher osteopontin mRNA expression than did MG63-IIIc. The enhanced osteoblastic marker gene expression and mineralized nodule formation of the MG63-Ap was inhibited by the conditioned medium from the COS-1 cells overexpressing the soluble FGFR2IIIcS252W. Furthermore the FGF2-induced osteogenic response in the mouse calvarial organ culture system was blocked by the soluble FGFR2IIIcS252W. These results show that the S252W mutation in the FGFR2 gene enhances the osteoblast phenotype in human osteoblasts and that a soluble FGFR2 with the S252W mutation controls osteoblast differentiation induced by the S252W mutation through a dominant negative effect on FGFR2 signaling in Apert syndrome.     

重组人粒细胞集落刺激因子缓释微球的研究

目的：研究固体／油／水法制备重组人粒细胞集落刺激因子缓释微球,为开发其缓释剂型进行初步研究。方法：以聚乳酸．聚羟乙酸共聚物（PLGA）为载体材料：用固体／油／水法和水／油／水法制备载rhG-CSF缓释微球;考察粒径大小、外观、包封率等理化性质;用MieroBCA法考察微球的体外释药特性及影响因素;用SEC-HPLC和MTT比色法初步评价了微球制备工艺过程对rhG-CSF稳定性的影响。结果：两种方法制得的微球形态圆整、分散性良好,包封率均超过80％。固／油／水法制得的微球体外释放在2周内可超过90％,而水／油／水法制得的微球在相同的时间内仅释放30％。对于固／油／水法制备过程,SEC-HPLC法测定蛋白无明显聚集体出现,MTT法测定蛋白活性无明显损失。结论：实验证明了固／油／水法制备的PLGA微球可以实现2周以上的体外缓释。     

光(温)敏核不育水稻花药和小孢子发生的细胞化学

利用细胞化学方法,对光（温）敏核不育水稻农垦585和W6154S的花药和小孢子发生过程的观察结果表明,在可育条件下,其花药组织和小孢子发生过程不论形态结构还是细胞化学变化都基本一致。小孢子母细胞时期的药隔薄壁组织、药壁中层及药室内壁中分布了一些多糖颗粒,但到进入减数分裂时多糖颗粒基本消失。绒毡层在解体前一直富含细胞质,从染色反应看,它表现为小孢子母细胞时期的蛋白质向减数分裂开始后的多糖物质的转变过程。在不育条件下,农垦585在小孢子母细胞时期就出现异常,其败有时间比W6154S要稍早一些。两者最后都表现为典败,但W6154S的花药壁解体较为彻底,只剩下干皱的表皮和药室内壁,而农垦585的花药壁还有多层细胞结构。     

Growth and reproduction of mice developed from bisected embryos

Embryos from three groups of mice, ICR (I), a synthetic (S), and an F(1) hybrid from C57BL males and S females (F), were used to examine effects of embryo bisection on subsequent viability, postnatal growth and reproduction. In two experiments, Group S females used as recipients received the following combinations of whole (W) and/or bisected (B) embryos: W(I) and W(F), W(I) and B(F), B(I) and W(F), and B(I) and B(F) in Experiment 1 and W(I) and W(S), W(I) and B(S), B(I) and W(S), and B(I) and B(S) in Experiment 2. Eight to 12 embryos of both types were transferred surgically to two horns of the uterus. Overall survival rate of whole embryos (32.6%) was significantly greater (P < 0.001) than that for demi-embryos (13.2%). The gestation period after transfer was significantly longer (P < 0.05) for demi-embryos (17.5d) than for whole embryos (16.4 d). Mice developed from demi and whole embryos were not different in mean body weight at birth and at 21, 42 and 63 d of age. Fertility and litter size at first parity of mice that developed from bisected embryos were comparable with those that developed from whole embryos. Hence, bisection decreased embryo viability, increased gestation period of recipients but did not affect postnatal growth and reproduction.     

Orientations and Proximities of the Extracellular Ends of Transmembrane Helices S0 and S4 in Open and Closed BK Potassium Channels

The large-conductance potassium channel (BK) α subunit contains a transmembrane (TM) helix S0 preceding the canonical TM helices S1 through S6. S0 lies between S4 and the TM2 helix of the regulatory β1 subunit. Pairs of Cys were substituted in the first helical turns in the membrane of BK α S0 and S4 and in β1 TM2. One such pair, W22C in S0 and W203C in S4, was 95% crosslinked endogenously. Under voltage-clamp conditions in outside-out patches, this crosslink was reduced by DTT and reoxidized by a membrane-impermeant bis-quaternary ammonium derivative of diamide. The rate constants for this reoxidation were not significantly different in the open and closed states of the channel. Thus, these two residues are approximately equally close in the two states. In addition, 90% crosslinking of a second pair, R20C in S0 and W203C in S4, had no effect on the V₅₀ for opening. Taken together, these findings indicate that separation between residues at the extracellular ends of S0 and S4 is not required for voltage-sensor activation. On the contrary, even though W22C and W203C were equally likely to form a disulfide in the activated and deactivated states, relative immobilization by crosslinking of these two residues favored the activated state. Furthermore, the efficiency of recrosslinking of W22C and W203C on the cell surface was greater in the presence of the β1 subunit than in its absence, consistent with β1 acting through S0 to stabilize its immobilization relative to α S4.     

Sites in TM2 and 3 are critical for alcohol-induced conformational changes in GABA receptors

Abstract gamma-Aminobutyric acid type A (GABA(A)) receptors are molecular targets for alcohols. Previous work suggests that S270 and A291 residues in the transmembrane (TM) 2 and 3 domains of the GABA(A) receptor alpha subunit are components of an alcohol-binding pocket, and S270I and A291W mutants abolished ethanol potentiation. Our results showed that A295C and F296C residues in the TM3 of the GABA(A) receptor alpha1 subunit are accessible to hexylmethanethiosulfonate (HMTS) in the alcohol-bound state, but not in the resting state. Thus, the A295C and F296C sites become water-accessible as a result of alcohol-induced conformational changes. If S270 or A291 residues are sites of alcohol binding, then S270I or A291W mutations should prevent alcohol-induced conformational movements within the TM3 domain. To investigate this question, the accessibility of HMTS reagent to double mutants (A291W/A295C, A291W/F296C, S270I/A295C or S270I/F296C) in the presence of ethanol or hexanol was tested. The A291W or S270I mutations markedly reduced the accessibility of HMTS to all the double mutants in the ethanol-bound state, and to S270I/F296C, A291W/A295C and A291W/F296C double mutants in the hexanol-bound state, suggesting that the A291 or S270 residues are critical sites for alcohol binding and alcohol-induced conformational changes.     

Microemulsion‐mediated removal of residual gasoline from soil columns

In situ pumping of micellular solutions of surfactant (S) and cosurfactant (CoS) in water (W) through contaminated soils or aquifers offers potential for enhanced remediation of residual nonaqueous‐phase liquids (NAPLs). Extremely low interfacial tension generated between a W/S/CoS mixture and residual NAPL in soil pores may initially mobilize the NAPL, which is then transported temporarily as a separate phase by immiscible displacement. The NAPL is then solubilized by micro‐emulsification as the W/S/CoS mixture forms a stable W/S/CoS/NAPL micro‐emulsion that undergoes miscible displacement through the pore space. This remediation technique was tested under laboratory conditions by sequentially flushing a saline solution and a W/S/CoS mixture through columns of a sandy soil recently contaminated with residual leaded gasoline (LG). Prior to the flushings, the soil was initially contaminated by applying a W/S/CoS/LG microemulsion. A simple conceptual transport model with kinetic clogging of soil pores adequately described breakthrough curves for gasoline and organolead in the soil columns.     

REVIEWS

The Land Now and To-morrow. By R. G. S tapledon
Genetics. By H. S. J ennings
Heredity and Evolution. By A. E. W atkins
Plant Biochemistry. By W. E. T ottingham
Éléments de chimie végétale. By N. W attiez and F. S tebnon
An Annotated Bibliography of the Low Temperature Relations of Plants. By K. B. H arvey
Weeds. By W. C. M uenscher
Ugressfrø (Unkrautsamen: Weed Seeds). By E mil K orsmo
British Stem- and Leaf-Fungi (Coeolomycetes). Vol. i. Spkaeropsidales. By W. B. G rove
Manual of the Grasses of the United States. By A. S. H itchcock     

Lipoxygenase metabolites of arachidonic and linoleic acids modulate the adhesion of tumor cells to endothelium via regulation of protein kinase C.

12(S)-hydroxyeicosatetraenoic acid (12[S]-HETE) and 13(S)-hydroxyoctadecadienoic acid (13[S]-HODE), lipoxygenase metabolites of arachidonic acid and linoleic acid, respectively, previously have been suggested to regulate tumor cell adhesion to endothelium during metastasis. Adhesion of rat Walker carcinosarcoma (W256) cells to a rat endothelial cell monolayer was enhanced after treatment with 12(S)-HETE and this 12(S)-HETE enhanced adhesion was blocked by 13(S)-HODE. Protein kinase inhibitors, staurosporine, calphostin C, and 1-(5-isoquinoline-sulfonyl)-2-methylpiperazine, inhibited the 12(S)-HETE enhanced W256 cell adhesion. Depleting W256 cells of protein kinase C (PKC) with phorbol 12-myristate-13-acetate abolished their ability to respond to 12(S)-HETE. Treatment of W256 cells with 12(S)-HETE induced a 100% increase in membrane-associated PKC activity whereas 13(S)-HODE inhibited the effect of 12(S)-HETE on PKC translocation. High-performance liquid chromatographic analysis revealed that in W256 cells 12-HETE and 13-HODE were two of the major lipoxygenase metabilites of arachidonic acid and linoleic acid, respectively. Therefore, these two metabolites may provide an alternative signaling pathway for the regulation of PKC. Further, these findings suggest that the regulation of tumor cell adhesion to endothelium by 12(S)-HETE and 13(S)-HODE may be a PKC-dependent process.     

Book reviews

Book reviewed in this article:
M icroalgae (1994) By E.W. Becker.
T he E volutionary B iology of V iruses (1994). Edited by S.S. Morse.
MCQ s in M edical M icrobiology and I nfectious D iseases (1993). By P.W. Ross and F.X.S. Emmanuel.
T uberculosis : B ack to T he F uture (1994). Edited by J.D.H. Porter and K.P.W. McAdam.
M aking S afe F ood : A M anagement G uide for M icrobiological Q uality (1991). By W.F. Harrigan and R.W.A. Park.
B acterial P rotein T oxins : FEMS S ymposium No. 73. (1994). Edited by J. Freer, R. Aitken, J.E. Alouf, G. Boulnois, P. Falmagne, F. Fehrenbach, C. Montecucco     

中国产龙葵数值分类的研究

本文通过对龙葵及变种黄果龙葵和少花龙葵的形态特征比较及系统聚类分析研究,认为可分为２个种及１个变种。