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1.
Aluminum (Al)-induced damage to leaves and roots of two Al-resistant (cv. Atlas 66, experimental line PT741) and two Al-sensitive (cv. Scout 66, cv. Katepwa) lines ofTriticum aestivum L. was estimated using the deposition of (1, 3)--glucans (callose) as a marker for injury. Two-day-old seedlings were grown for forty hours in nutrient solutions with or without added Al, and callose deposition was quantified by spectrofluorometry (0–1000 µM Al) and localized by fluorescence microscopy (0 and 400 µM Al). Results suggested that Al caused little damage to leaves. No callose was observed in leaves with up to 400 µM Al treatment. In contrast, root callose concentration increased with Al treatment, especially in the Al-sensitive lines. At 400 µM Al, root callose concentration of Al-sensitive Scout 66 was nearly four-fold that of Al-resistant Atlas 66. After Al treatment, large callose deposits were observed in the root cap, epidermis and outer cortex of root tips of Scout 66, but not Atlas 66. The identity of callose was confirmed by a reduced fluorescence in Al-treated roots: firstly, after adding an inhibitor of callose synthesis (2-deoxy-D-glucose) to the nutrient solution, and secondly, after incubating root sections with the callosedegrading enzyme -D-glucoside glucohydrolase [EC 3.2.1.21]. Root callose deposition may be a good marker for Al-induced injury due to its early detection by spectrofluorometry and its close association with stress perception.Abbreviations DDG 2-deoxy-D-glucose - PAS periodic acid - Schiffs reagent - PE pachyman equivalents  相似文献   

2.
Mixed membrane preparations from the coleoptiles and first leaves of young barley (Hordeum vulgare L. cv. Triumph) plants catalysed the synthesis of 55% methanol-insoluble labelled material from UDP[U-14C]glucose, the main components of which were identified as (1,3)(1,4)-- and (1,3)--D-glucans. The membrane preparations also catalysed the transformation of UDP-glucose into labelled low-molecular-weight products, mainly glucose (by phosphatase action), glucose-1-phosphate (by phosphodiesterase action) and glyco(phospho)lipids (by glycosyltransferase action). The formation of (1,3)(1,4)--glucans, (1,3)--glucans, and the other reactions competing for UDP-glucose, were monitored simultaneously and quantitatively by a novel procedure based on enzymatic analysis, thin-layer chromatography and digital autoradiography. Thus it was possible (i) to optimise conditions to obtain (1,3)(1,4)--glucan synthesis or (1,3)--glucan synthesis in isolation, and (ii) to study the influence of temperature, pH, cofactors, substrate concentration etc. on the (1,3)(1,4) and (1,3)--glucan synthesis reactions even when both occurred together. The synthesis of both -glucans was optimal at 20°C. In Tris-HCl buffer, the pH optima for (1,3)(1,4)--glucan synthesis and (1,3)--glucan synthesis were pH 8.5 and pH 7.0, respectively. Both glucan-synthesis reactions required Mg2+: (1,3)--glucan synthesis was optimal at 2 mM, whereas (1,3)(1,4)--glucan synthesis continued to increase up to 200 mM Mg2+, when the ion was supplied as the sulphate. (1,3)--Glucan synthesis was Ca2+ dependent and this dependence could be abolished by proteinase treatment. The K m with respect to UDP-glucose was 1.5 mM for (1,3)--glucan synthesis and approximately 1 mM for (1,3)(1,4)--glucan synthesis. The (1,3)(1,4)--glucan formed in vitro had the same ratio of trisaccharide to tetrasaccharide structural blocks irrespective of the experimental conditions used during the synthesis: its enzymatic fragmentation pattern was indistinguishable from that of barley endosperm (1,3)(1,4)--glucan. This indicates either a single synthase enzyme, which is responsible for the formation of both linkage types, or two enzymes which are very tightly coupled functionally.Abbreviations G4G4G3G Glc(1,4)Glc(1,4)Glc(1,3)Glc (-linked) - UDP-Glc uridine-5-diphosphate glucose We are grateful to the Commission of the European Communities for the award of Training Fellowships to Christine Vincent and Martin Becker.  相似文献   

3.
4.
Essential oils from Erodium cicutarium were obtained by hydrodistillation (samples consisting of entire plants (ec1), leaves and stems (ec2)) and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS), resulting in a total of 177 components being identified. The essential oils were of a very similar chemical composition and consisted mainly of aliphatic compounds and their derivatives. Fatty acids and fatty acid derived compounds were the most common, 51.3% (ec1) and 60.1% (ec2), followed by carotenoid derived compounds, 12.6% (ec1) and 20.2% (ec2), and then terpenoids, 14.9% (ec1) and 14.2% (ec2). The main constituents in the oils were hexadecanoic acid, 22.8% (ec2) and 35.9% (ec1) and hexahydrofarnesyl acetone, 10.8% (ec2) and 11.6% (ec1). The results obtained differ markedly from those previously reported for the same species.  相似文献   

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6.
TYRO3、AXL和MER受体是受体酪氨酸激酶亚家族之一,广泛地表达在哺乳动物神经、免疫、生殖、血液等系统多种细胞中,促进细胞存活、增殖和分化。本研究利用基因芯片技术筛选基因敲除的TYRO3~(~(-/-))AXL~(-/-)MER~(-/-)小鼠骨髓细胞中差异性表达的m RNA,并进行生物信息学分析。与正常小鼠骨髓细胞相比,TYRO3~(-/-)AXL~(-/-)MER~(-/-)小鼠骨髓细胞中差异表达基因探针共1 363条,其中表达上调的基因探针499条、下调的基因探针864条。GO功能富集分析发现上调的基因主要参与免疫反应,下调的基因主要参与造血。KEGG Pathway富集分析发现上调的基因主要参与细胞粘附分子和抗原呈递等信号通路。Real-time PCR验证5个差异基因,与芯片中表达变化趋势一致。因此TYRO3、AXL和MER受体共同参与调控机体的免疫反应和血细胞分化。  相似文献   

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Summary Weeds and among themAmbrosia are probably the most important vascular plants related to pollinosis in Hungary. Sampling was carried out in central (Budapest) and in southern (Paks, Szeged) Hungary. The results of two years (1989–1990) of aerobiological study onAmbrosia airborne pollen are reported. The highest percentage of airborne pollen was found in the mid-August to mid-September period, having a good correlation with clinical data on pollinosis. The implications of these results are considered in the context of forecasting and prevention of seasonal ragweed pollinosis.  相似文献   

9.
Résumé La jeune spermatide possède un noyau arrondi, un diplosome proche de la membrane cellulaire auquel sont associées des formations paracentriolaires; une mitochondrie unique est disposée entre le diplosome et le noyau.Au cours de l'évolution de la spermatide, le noyau s'allonge latéralement, son grand axe étant perpendiculaire à l'axe flagellaire; la mitochondrie migre à l'extrémité latérale du noyau; le centriole distal donne un flagelle de type 9+0; le centriole proximal se prolonge le long du noyau puis sort de la cellule sous la forme d'un pseudo-flagelle. Le prolongement centriolaire est constitué de triplets classiques et de doublets d'un type particulier que nous avons appelés «doublets A–C».Les auteurs signalent la similitude des spermatozoïdes de cet Elopiforme avec les spermatozoïdes d'Anguilliformes ce qui serait en faveur de la proposition de Greenwood et al. de rassembler ces téléostéens dans le super-ordre des Elopomorphes.
The spermiogenesis of Albula vulpes (L. 1758) (albulidae fish)
Summary The early spermatid possesses a round nucleus and a diplosome which is close to the cellular membrane and with which paracentriolar formations are associated; a sole mitochondrion is located between the diplosome and the nucleus.During the spermatid evolution, the nucleus is laterally elongated, its main axis being perpendicular to the flagellar axis; the mitochondrion migrates towards the lateral end of the nucleus; the distal centriole is extended along the nucleus, then leaves the cell as a pseudoflagellum. This centriolar extension is made up of regular triplets and of a particular type of doublets that we have called A–C doublets.The authors call attention to the similarity between the spermatozoa of this Elopiforme and the spermatozoa of the Anguilliformes. This observation favours Greenwood et al.'s proposition, to place these teleost into the super-order of Elopomorpha.
Les auteurs tiennent à remercier Mr. C. Chauve et Mr. J.-N. Roy pour leur collaboration.  相似文献   

10.
Albert Léon Charles Calmette was the first person to develop an anti-venom serum. His work revolutionized the treatment of snakebite in men and domestic animals. He is also well known for his development of the Bacillus Calmette-Guérin (BCG) vaccine for the prevention of tuberculosis. This article reviews the life experiences of this pioneer bioscientist, the current status of BCG in preventing tuberculosis, and the potential of BCG in immunotherapy for cancer.  相似文献   

11.
(S)-(?)-Vertinolide 1 was synthesized via the tetronic acid derivative 6 from (S)-(?)-tetrahydro-2-methyl-5-oxo-2-furancarboxylic acid 3. (±)-Vertinolide was also synthesized from (±)-3.  相似文献   

12.
Two major forms of branching enzyme from developing kernels of maize have been detected after DEAE-cellulose chromatography. Branching-enzyme I, which contained 24% of the activity based on a phosphorylase-stimulation assay, but 74% of the activity based on the branching of amylose as monitored by change in spectra of the iodine-glucan complex, eluted with the column wash and was unassociated with starch-synthase activity. Branching-enzyme II was bound to DEAE-cellulose and was coeluted with both primed and unprimed starch-synthase activities. Both fractions were further purified by chromatography on aminoalkyl-Sepharose columns. Single peaks were observed for both fractions by gel filtration on BioGel A1.5m columns and native molecular weights were estimated at 70,000–90,000 for both enzymes. Subunit molecular weights of branching-enzymes I and II were estimated by dodecyl sodium sulfate-gel electrophoresis at 89,000 and 80,000, respectively. Thus both enzymes are primarily monomeric. Branching-enzymes I and II could be distinguished by chromatography on DEAE-cellulose or 4-aminobutyl-Sepharose, and by disc-gel electrophoresis with activity staining. Branching-enyme I had a lower ratio of activity (phosphorylase stimulation-amylose branching; based on enzyme units). The ratio varied from 30–60 as compared to about 300–500 for branching-enzyme II. Likewise, branching-enzyme I had a lower Km value for amylose than branching- enzyme II, the values being 160 and 500 μg/ml, respectively. Both enzymes could introduce further branches into amylopectin, as decreases in the overall absorption and wavelength maxima of the iodine complexes were observed. Combined action of the branching enzymes and rabbit-muscle phosphorylase a (12:1 ratio based on enzyme units) resulted in similar patterns of incorporation of d-glucose into the growing α-d-glucan and the synthesis of high molecular-weight polymers. However, the α-d-glucans differed, as shown by spectra of iodine complexes and average unit-chain length. Branching-enzyine II was separated into two fractions (IIa and IIb) by chromatography on 4-aminobutyl-Sepharose. These Fractions differed only in the branching of amylopectin, fractional IIb being more active than IIa.  相似文献   

13.
For use as the internal standards in a quantitative analysis of natural jasmonic acid (JA) and methyl jasmonate (JAMe) by gas chromatography-mass spectrometry-selected ion monitoring, (±)-2-(2,3–2H2)JA and its methyl ester, (±)-2-(2,3–2H2)JAMe, were efficiently prepared from 2-(2–pentyl)-2-cyclopentenone through catalytic semi-deuteriogenation of acetylenic intermediates with deuterium gas in pyridine.  相似文献   

14.
本文首次采用田间试验的方法对国内油菜收获指数的变异进行了研究.结果表明不同油菜品种的收获指数存在变异,其变异规律大致是:1)中熟品种的收获指数高于早熟品种及晚熟品种;2)中长角果的品种较长角品种具有更高的收获指数;3)高产的新品种具有较高的收获指数;4)油菜粒壳比,角杆比及千粒重与收获指数呈正相关,杆重与收获指数呈负相关.  相似文献   

15.
正蜘蛛是节肢动物门Arthropoda蛛形纲Arachnida蜘蛛目Araneae)种的通称。《应用昆虫学报》不仅发表昆虫(节肢动物门的昆虫纲Insecta)的各类研究成果,同时也从广义角度关注蜘蛛等相关研究成果的报道。本期封面照片为白斑跳珠Evarcha albaria (L. Koch)(跳蛛科Salticidae,李枢强鉴定物种名称,张润志拍摄照片),2020年9月26日拍摄于天津宝坻周良庄。  相似文献   

16.
Clestobothrium neglectum (Lönnberg, 1893) n. comb. is redescribed from specimens previously deposited in The Natural History Museum, London, UK by Dr David I. Gibson obtained from the intestine of the tadpole fish Raniceps raninus (Gadidae) collected from off the western coast of Sweden, near Kristineberg. C. neglectum resembles C. crassiceps (Rudolphi, 1819), the type- and only species currently recognised in the genus, but differs in having fine spiniform-like structures that are likely microtriches covering the posterior fourth of the scolex and all proglottids, a highly folded tegument forming numerous longitudinal ridges on both the dorsal and ventral surfaces of the proglottids giving them a scalloped appearance, a somewhat smaller egg (68 × 35 vs 75 × 40 μm), a U-shaped rather than H-shaped ovary and more testes (70–85 vs 40–50 per proglottid). C. neglectum is also compared to two species with similar scoleces that were previously assigned to Clestobothrium, Bothriocephalus acheilognathi Yamaguti, 1934 and B. kivuensis Baer &; Fain, 1958 (considered to be synonymous with B. acheilognathi by Pool, 1987). This is the first report of a species of Clestobothrium Lühe, 1899 (Bothriocephalidae) from a gadid fish.  相似文献   

17.
We found a potent platelet aggregation inhibitor in the culture broth of Streptomyces strain M-193. The inhibitor was purified as white crystals and investigated; it was identified as staurosporine. It strongly inhibited the platelet aggregation induced by collagen or ADP with IC50 values of 3.4 μm, and 11.6 μm, respectively. The inhibitor had no effect on thrombin-induced platelet aggregation or membrane stabilization against heat-induced hemolysis.  相似文献   

18.
高翼之 《遗传》2006,28(3):255-256
1903年10月22日,乔治·威尔斯·比德尔(G.W.Beadle)出生于美国内布拉斯加州一户农民家庭,1926年和1927年先后获内布拉斯加林肯大学理科学士和硕士学位。尔后,他到康奈尔大学,在遗传学大师爱默生(Emerson)领导的“玉米小组”攻读博士学位,从事玉米细胞遗传学研究。1931年获博士学位后,他又到加州理工学院,在遗传学大师摩尔根(Morgan)领导的“蝇室”从事果蝇细胞遗传学研究。1936年,他到哈佛大学任助理教授,1937~1946年任斯坦福大学教授,1946年回到加州理工学院任教授和生物学系主任,1961~1968年任芝加哥大学校长。比德尔和泰特姆(Tatum)以…  相似文献   

19.
Immunogold labeling was used to study the distribution of (1 → 3)-β-glucans and (1 → 3, 1 → 4)-β-glucans in the rice grain during cellularization of the endosperm. At approximately 3–5 d after pollination the syncytial endosperm is converted into a cellular tissue by three developmentally distinct types of wall. The initial free-growing anticlinal walls, which compartmentalize the syncytium into open-ended alveoli, are formed in the absence of mitosis and phragmoplasts. This stage is followed by unidirectional (centripetal) growth of the anticlinal walls mediated by adventitious phragmoplasts that form between adjacent interphase nuclei. Finally, the periclinal walls that divide the alveoli are formed in association with centripetally expanding interzonal phragmoplasts following karyokinesis. The second and third types of wall are formed alternately until the endosperm is cellular throughout. All three types of wall that cellularize the endosperm contain (1 → 3)-β-glucans but not (1 → 3, 1 → 4)-β-glucans, whereas cell walls in the surrounding maternal tissues contain considerable amounts of (1 → 3, 1 → 4)-β-glucans with (1 → 3)-β-glucans present only around plasmodesmata. The callosic endosperm walls remain thin and cell plate-like throughout the cellularization process, appearing to exhibit a prolonged juvenile state. Received: 7 January 1997 / Accepted: 11 February 1997  相似文献   

20.
V práci byly studovány rozdíly v ú?innosti kyseliny β-(3-pyridyl)-propionové (VIII) a β-(3-pyridyl)-akrylové (IX) v závislosti na stupni nenasycení pobo?ného ?etězce. Obě kyseliny inhibují r?st ko?ene i hypokotyluSinapis alba L. a zp?sobují inhibici sukcinátdehydrogenázového enzymového systému. Kyselina IX inhibuje zmíněný systém p?ibli?ně na dvojnásobek inhibice kyseliny VIII. Cytochromoxydázový systém z?stává témě? neovlivněn. Na základě experimen tálních výsledk? byla zp?esněna strukturní podmínka fytotoxické aktivity modelových slou?enin typu I v tom smyslu, ?e v?echny slou?eniny této struktury inhibují kromě r?stu také aktivitu sukcinátdehydrogenázového systému.  相似文献   

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