塔克拉玛干沙漠耐旱,耐盐植物种的选择

塔克拉玛干沙漠耐旱、耐盐植物种的选择刘家琼,邱国玉,石庆辉,李风琴（中国科学院兰州沙漠研究所沙坡头沙漠试验研究站,７３００００）ＳｅｌｅｃｔｉｏｎｏｆＤｒｏｕｇｈｔ－ＲｅｓｉｓｔａｎｔａｎｄＳａｌｔ－ＴｏｌｅｒａｎｔＰｌａｎｔＳｐｅｃｉｅｓｉｎｔｈｅ...     

吐鲁番盆地鄯善地区中、晚侏罗世介形类

报道吐鲁番盆地连木沁剖面七克以组及齐古组的介形类化石３属１０种,其中２新种１未定种;Ｔｈｅｒｉｏｓｙｎｏｅｃｕｍ？ｑｉｋｔｉｍｅｎｓｉｓ ｓｐ．ｎｏ。,Ｔｈ．ｈｕｏｙａｎｓｈａｎｅｎｉｓ ｓｐ．ｎｏｖ．,Ｄａｒｗｉｎｕｌａ ｓｐ．,根据化石组合面貌,自上而下可建立两个组合,即Ｄａｒｗｉｎｕｌａ－Ｍｅｔａｃｙｐｒｉｓ组合和Ｔｈｅｒｉｏｓｙｎｏｅｃｕｍ？－Ｄａｒｗｉｎｕｌａ组合,其时代分别为晚侏罗世和     

肉苁蓉的胚胎发育

肉苁蓉的胚胎发育马红,屠骊珠,李天然（内蒙古大学生物系,呼和浩特０１００２１）寄生植物肉苁蓉（Ｃｉｓｔａｎｃｈｅｄｅｓｅｒｔｉｃｏｌａ）为多年生根寄生草本植物,是我国西北沙漠地区重要的中药材,可补精血,滋肾壮阳,润肠通便,因此有“沙漠人参”之称。关于...     

沙漠绿化改造的基础研究──白菜盆栽试验的统计解析

沙漠绿化改造的基础研究白菜盆栽试验的统计解析金凤鹤西崎泰山口达明尹怀宁白鸿祥郑应顺（日本千叶工业大学）（辽宁师范大学，大连１１６０２９）ＰｒｉｍａｒｙＲｅｓｅａｒｃｈｏｆＤｅｓｅｒｔＰｌａｎｔＲｅｆｏｒｍｉｎｇＴｈｅＳｔａｔｉｓｔｉｃｓＡｎａｌｙｓ...     

华北铜川组爬行动物化石的首次发现及其地层意义

１９９２年,中国科学院古脊椎动物与古人类研究所从人民来信中得知,在山西永和县桑壁镇附近的河沟中发现了陆生四足动物化石。不久古脊椎所的专业人员就到化石产地进行了实地调查,并发掘出了几具保存较好的爬行动物化石。化石保存在坚硬的细砂岩中,已经修理出其中一个头骨（如图１所示）。经初步鉴定,这批化石是一类初龙形类动物,与产自新疆吐鲁番盆地中三叠世克拉玛依组的达板吐鲁番鳄（Ｔｕｒｆａｎｏｓｕｃｈｕｓｄａｂａｎｅｎｓｉｓ）（Ｙｏｕｎｓ,１９７３）关系较近,但是其内颈动脉孔位于基蝶骨侧面,而不是位于腹面,这表明…     

新疆吐鲁番─哈密盆地晚三叠世黄山街组、郝家沟组孢粉植物群及其意义

本文对新疆吐鲁番－哈密盆地３口石油探井中黄山街组、郝家沟组共１０８块样品进行了孢粉分析研究。自下而上建立了晚三叠世两个孢粉组合,即Ａｒａｔｒｉｓｐｏｒｉｔｅｓ－Ａｌｉｓｐｏｒｉｔｅｓ组合和Ｏｓ－ｍｕｎｄａｃｉｄｉｔｅｓ－Ｃｈｏｒｄａｓｐｏｒｉｔｅｓ组合,讨论了组合特征及其时代,并与国内外有关层位及化石群进行了分析比较;探讨了孢粉植物群所反映的古植被和古气候。     

新疆吐鲁番—哈密盆地晚三叠世黄山街组,郝家沟组孢粉植物群及其意义

本文对新疆吐鲁番－哈密盆地３口石油探井中黄山街组,郝家沟组共１０８块样品进行了孢粉分析研究。自下而上建立了晚三叠世两个孢粉组合,即Ａｒａｔｒｉｓｐｏｒｉｔｅｓ－Ａｌｉｓｐｏｒｉｔｅｓ组合和Ｏｓｍｕｎｄａｃｉｄｉｔｅｓ－Ｃｈｏｒｄａｓｐｏｒｉｔｅｓ组合,讨论了组合特征及其时代,并与国内外有关层位及化石群进行了分析比较;探讨了孢粉植物群所反映的古植被和古气候。     

关于为全国中小学教师、科技辅导员举办首届高山植物、沙生植物研讨班的通知

为庆祝中国植物学会成立60周年,满足广大教师的愿望,新疆植物学会及其挂靠单位中科院新疆生物土壤沙漠所,定于1993年暑期举办全国首届高山植物、沙生植物中小学教师科技辅导员研讨会. 一、会议内容:1.中国科学院吐鲁番沙漠植物园、葡萄沟等地考察、采集;2.吐鲁番古迹、高昌古城、火焰山考察;3.胜利大坂亚洲一号冰川景观考察、采集;4.天池景观及阜康荒漠生态站原始梭梭林考察、采集;5.库尔班通古特沙漠考察、采集;6.参观中科院生物土壤沙漠     

雪豹下天山之谜

2005年5月3日上午,新疆汽车环塔克拉玛干拉力赛第二赛段的比赛,正在吐鲁番附近的沙漠戈壁上如火如荼地进行之中。     

奇特的仙人掌类植物

1　金琥金琥属 (ＥｃｈｉｎｏｃａｃｔｕｓＩｎｋｅｔＯｔｔｏ.)是强刺球类的代表 ,原产墨西哥中部干燥炎热的沙漠地带。此属植物是仙人掌类中最具魅力的一类植物。金琥又称象牙球 (ＥｃｈｉｎｏｃａｃｔｕｓｇｒｕｓｏｎｉｌＨｉｌｄｍ .) ,它那浑圆碧绿的球体 ,钢硬的金黄色硬刺 ,令人赏心悦目。球体的直径可达 1米左右。球体顶部密生一圈金黄色的绒毛。自顶部向下有 2 1～ 2 7个棱脊高耸的直棱 (一般仙人球只有棱 12～ 14个 )。棱上整齐排列较大的刺座。在刺座上密生金黄色辐射状刺 8～ 10枚 ,强硬稍弯的金黄色中刺 3～ 4枚。成年植物每…     

Isolation of BamHI variants with reduced cleavage activities

Derivation of the bamhIR sequence (Brooks, J. E., Nathan, P.D., Landry, D., Sznyter, L.A., Waite-Rees, P., Ives, C. C., Mazzola, L. M., Slatko, B. E., and Benner, J. S. (1991) Nucleic Acids Res., in press), the gene coding for BamHI endonuclease, has facilitated construction of an Escherichia coli strain that overproduces BamHI endonuclease (W. E. Jack, L. Greenough, L. F. Dorner, S. Y. Xu, T. Strezelecka, A. K. Aggarwal, and I. Schildkraut, submitted for publication). As expected, low-level constitutive expression of the bamhIR gene in E. coli from the Ptac promotor construct is lethal to the host unless the bamHIM gene, which encodes the BamHI methylase, is also expressed within the cell. We identified four classes of BamHI endonuclease variants deficient in catalysis by selecting for survival of a host deficient for bamHIM gene, transformed with mutagenized copies of the bamhIR gene, and then screening the surviving cell extracts for DNA cleavage and binding activities. Class I variants (G56S, G91S/T153I, T114I, G130R, E135K, T153I, T157I, G194D) displayed 0.1-1% of the wild-type cleavage activity; class II variant (D94N) lacked cleavage activity but retained wild-type DNA binding specificity; class III variants (E77K, E113K) lacked cleavage activity but bound DNA more tightly; class IV variants (G56D, G90D, G91S, R122H, R155H) lacked both binding and cleavage activities. Variants with residual cleavage activities induced the E. coli SOS response and thus are presumed to cleave chromosomal DNA in vivo. We conclude that Glu77, Asp94, and Glu113 residues are essential for BamHI catalytic function.     

Ultrastructural characterization of embryonic chick cartilage proteoglycan core protein and the mapping of a monoclonal antibody epitope.

The ultrastructure of embryonic chick cartilage proteoglycan core protein was investigated by electron microscopy of specimens prepared by low angle shadowing. The molecular images demonstrated a morphological substructural arrangement of three globular and two linear regions within each core protein. The internal globular region (G2) was separated from two terminally located globular regions (G1 and G3) by two elongated strands with lengths of 21 +/- 3 nm (E1) and 105 +/- 22 nm (E2). The two N-terminal globular regions, separated by the 21-nm segment, were consistently visualized in well spread molecules and showed little variation in the length of the linear segment connecting them. The E2 segment, however, was quite variable in length, and the C-terminal globular region (G3) was detected in only 53% of the molecules. The G1, G2, and G3 regions in chick core protein were 10.1 +/- 1.7 nm, 9.7 +/- 1.3 nm, and 8.3 +/- 1.3 nm in diameter, respectively. These results are similar to those described previously for proteoglycan core proteins isolated from rat chondrosarcoma, bovine nasal cartilage, and pig laryngeal cartilage (Paulsson, M., Morgelin, M., Wiedemann, H., Beardmore-Gray, M., Dunham, D., Hardingham, T., Heinegard, D., Timpl, R., and Engel, J. (1987) Biochem. J. 245, 763-772). However, a significant difference was detected between the length of the elongated strand (E2) of core proteins isolated from chick cartilage, E2 length = 105 +/- 22 nm, compared to bovine nasal cartilage, E2 length = 260 +/- 39 nm. The epitope of the proteoglycan core protein-specific monoclonal antibody, S103L, was visualized by electron microscopy, and the distance from the core protein N terminus to the S103L binding site was measured. The S103L binding site was localized to the E2 region, 111 +/- 20 nm from the G1 (N terminus) domain and 34 nm from the G3 (C terminus) domain. cDNA clones selected from an expression vector library of chicken cartilage mRNA also show this epitope to be located near the C-terminal region (R. C. Krueger, T. A. Fields, J. Mensch, and B. Schwartz (1990) J. Biol. Chem. 265, 12088-12097).     

Structure-activity studies of the inhibition of FabI,the enoyl reductase from Escherichia coli,by triclosan: kinetic analysis of mutant FabIs

Triclosan, a common antibacterial additive used in consumer products, is an inhibitor of FabI, the enoyl reductase enzyme from type II bacterial fatty acid biosynthesis. In agreement with previous studies [Ward, W. H., Holdgate, G. A., Rowsell, S., McLean, E. G., Pauptit, R. A., Clayton, E., Nichols, W. W., Colls, J. G., Minshull, C. A., Jude, D. A., Mistry, A., Timms, D., Camble, R., Hales, N. J., Britton, C. J., and Taylor, I. W. (1999) Biochemistry 38, 12514-12525], we report here that triclosan is a slow, reversible, tight binding inhibitor of the FabI from Escherichia coli. Triclosan binds preferentially to the E.NAD(+) form of the wild-type enzyme with a K(1) value of 23 pM. In agreement with genetic selection experiments [McMurry, L. M., Oethinger, M., and Levy, S. B. (1998) Nature 394, 531-532], the affinity of triclosan for the FabI mutants G93V, M159T, and F203L is substantially reduced, binding preferentially to the E.NAD(+) forms of G93V, M159T, and F203L with K(1) values of 0.2 microM, 4 nM, and 0.9 nM, respectively. Triclosan binding to the E.NADH form of F203L can also be detected and is defined by a K(2) value of 51 nM. We have also characterized the Y156F and A197M mutants to compare and contrast the binding of triclosan to InhA, the homologous enoyl reductase from Mycobacterium tuberculosis. As observed for InhA, Y156F FabI has a decreased affinity for triclosan and the inhibitor binds to both E.NAD(+) and E.NADH forms of the enzyme with K(1) and K(2) values of 3 and 30 nM, respectively. The replacement of A197 with Met has no impact on triclosan affinity, indicating that differences in the sequence of the conserved active site loop cannot explain the 10000-fold difference in affinities of FabI and InhA for triclosan.     

Regulated interactions of the alpha 2A adrenergic receptor with spinophilin, 14-3-3zeta,and arrestin 3

The present studies demonstrate that no single stretch of sequence in the third intracellular (3i) loop of the alpha(2A) adrenergic receptor (alpha(2A)-AR) can fully account for its previously described interactions with spinophilin (Richman, J. G., Brady, A. E., Wang, Q., Hensel, J. L., Colbran, R. J., and Limbird, L. E. (2001) J. Biol. Chem. 276, 15003-15008), 14-3-3zeta (Prezeau, L., Richman, J. G., Edwards, S. W., and Limbird, L. E. (1999) J. Biol. Chem. 274, 13462-13469), and arrestin 3 (Wu, G., Krupnick, J. G., Benovic, J. L., and Lanier, S. M. (1997) J. Biol. Chem. 272, 17836-17842), suggesting that a three-dimensional surface, rather than a linear sequence, provides the basis for these interactions as proposed for 3i loop tethering of the alpha(2A)-AR to the basolateral surface of Madin-Darby canine kidney cells (Edwards, S. W., and Limbird, L. E. (1999) J. Biol. Chem. 274, 16331-16336). Sequences at the extreme N-terminal and C-terminal ends of the 3i loop are critical for interaction with spinophilin but not for interaction with 14-3-3zeta or arrestin 3, for which the C-terminal half of the loop is more important. Competition binding for (35)S-labeled alpha(2A)-AR 3i loop binding to glutathione S-transferase (GST)-spinophilin amino acids 151-444 revealed a relative affinity of spinophilin congruent with arrestin > 14-3-3zeta for the unphosphorylated alpha(2A)-AR 3i loop. Agonist occupancy of the alpha(2A)-AR increases receptor association with spinophilin, and arrestin 3 appears to compete for this enrichment. However, when the G protein-coupled receptor kinase 2 substrate sequence was deleted from the 3i loop, arrestin 3 could not compete for the agonist-enriched binding of spinophilin to the mutant alpha(2A)-AR. These data are consistent with a model where sequential or competitive interactions among spinophilin, arrestin, and/or 14-3-3zeta play a role in alpha(2A)-AR functions.     

The E and G subunits of the yeast V-ATPase interact tightly and are both present at more than one copy per V1 complex

The E and G subunits of the yeast V-ATPase are believed to be part of the peripheral or stator stalk(s) responsible for physically and functionally linking the peripheral V1 sector, responsible for ATP hydrolysis, to the membrane V0 sector, containing the proton pore. The E and G subunits interact tightly and specifically, both on a far Western blot of yeast vacuolar proteins and in the yeast two-hybrid assay. Amino acids 13-79 of the E subunit are critical for the E-G two-hybrid interaction. Different tagged versions of the G subunit were expressed in a diploid cell, and affinity purification of cytosolic V1 sectors via a FLAG-tagged G subunit resulted in copurification of a Myc-tagged G subunit, implying more than one G subunit was present in each V1 complex. Similarly, hemagglutinin-tagged E subunit was able to affinity-purify V1 sectors containing an untagged version of the E subunit from heterozygous diploid cells, suggesting that more than one E subunit is present. Overexpression of the subunit G results in a destabilization of subunit E similar to that seen in the complete absence of subunit G (Tomashek, J. J., Graham, L. A., Hutchins, M. U., Stevens, T. H., and Klionsky, D. J. (1997) J. Biol. Chem. 272, 26787-26793). These results are consistent with recent models showing at least two peripheral stalks connecting the V1 and V0 sectors of the V-ATPase and would allow both stalks to be based on an EG dimer.     

Two new species of Araceae tribe Spathicarpeae from Bolivia

The tribe Spathicarpeae is one of the most poorly known-tribes in the Araceae. Recently, field collections in some areas of Bolivia have revealed many interesting members of this tribe. Two new species,Gorgonidium striatum Hett., P. L. Ibisch &; E. G. Gonç. andSpathantheum fallax Hett., P. L. Ibisch &; E. G. Gonç. are here described, illustrated, and compared to their closest relatives.     

Dependence of the bi-functional nature of a sialyltransferase from Neisseria meningitidis on a single amino acid substitution

The L1 immunotype strain 126E of Neisseria meningitidis has been shown to have an N-acetyl-neuraminic acid-containing lipooligosaccharide in which an alpha-linked galactose from a P(k) epitope is substituted at the O6 position (Wakarchuk, W. W., Gilbert, M., Martin, A., Wu, Y., Brisson, J. R., Thibault, P., and Richards, J. C. (1998) Eur. J. Biochem. 254, 626-633). Using a synthetic P(k)-epitope containing acceptor in glycosyltransferase reactions, we were able to show by NMR analysis of the reaction product that the 126E(L1)-derived sialyltransferase can make both alpha-2,3 and alpha-2,6 linkages to the terminal galactose. Gene disruption experiments showed that the lst gene in 126E(L1) was responsible for the in vivo addition of the alpha-2,6-linked N-acetyl-neuraminic acid residue. By site-directed mutagenesis it was possible to change the MC58(L3)-derived enzyme into a bifunctional enzyme with a single amino acid change at position 168, where a glycine was changed to an isoleucine. We performed a gene replacement experiment where the 126E(L1) alpha-2,3/6-sialyltransferase was replaced by allelic exchange with the monofunctional MC58(L3) alpha-2,3-sialyltransferase and with the mutant MC58(L3) allele G168I. We observed that the level of LOS sialylation with the G168I allele was very similar to that of the wild type 126E(L1), indicating that residue 168 is the critical residue for the alpha-2,6-sialyltransferase activity in vitro as well as in vivo.     

Histidine decarboxylase of Lactobacillus 30a. Sequences of the overlapping peptides, the complete alpha chain, and prohistidine decarboxylase

The complete amino acid sequence of the alpha chain of histidine decarboxylase of Lactobacillus 30a has been established by isolation and analysis of the eight methionine-containing tryptic peptides of this chain. These peptides provide the overlaps required to order all nine peptides derived by complete cyanogen bromide cleavage of the alpha chain (Huynh, Q.K., Vaaler, G.L., Recsei, P.A., and Snell, E.E. (1984) J. Biol. Chem. 259, 2826-2832). Ordering of six of the latter peptides was confirmed by isolation and analysis of four peptides derived by incomplete cyanogen bromide cleavage. The alpha chain is composed of 226 residues and has a molecular weight of 24,892 calculated from the sequence. These results and the previously determined sequence of the beta chain (Vaaler, G.L., Recsei, P.A., Fox, J.L., and Snell, E.E. (1982) J. Biol. Chem. 257, 12770-12774) establish the complete amino acid sequence of the enzyme and of the pi chain of prohistidine decarboxylase. The latter is composed of 307 amino acids and has a calculated molecular weight of 33,731. Four segments of the pi chain sequence are repeated. The bond between Ser-81 and Ser-82 that is cleaved during proenzyme activation is in an uncharged portion of the sequence that is rich in serine and threonine residues and is predicted to be part of a beta sheet structure.     

BUCHBESPRECHUNGEN

L eakey , L. S. B., and S avage , R. J. G. (Ed.): Fossil Vertebrates of Africa. Vol. 2 .
N aaktgeboren , C., und S lijper , E. J.: Biologie der Geburt .
W illiams , J ohn G.: Sägetiere und seltene Vögel in den Nationalparks Ostafrikas .     

Book Reviews

Book reviewed in this article:
Sir Joseph Banks. A Global Perspective. Ed. Banks, R.E.R., Elliot, B., Hawkes, J.G., King-Hele, D., and Lucas, G.L.
Dictionary of British and Irish Botanists and Horticulturalists, including Plant Collectors, Flower painters and Garden Designers. Desmond, Ray.