Nitrogen metabolism of Plantago major ssp. major as dependent on the supply of mineral nutrients

Various aspects of the nitrogen metabolism of Plantago major L. ssp. major , a grassland species from a relatively nutrient-rich habitat, were investigated with plants that were grown in nutrient-rich and nutrient-poor culture solutions. In addition the influence of a change in the nutrient supply, both from high to low and from low to high nutrient conditions was studied. The data on P. major major showed that the activities of nitrate reductase (NR) and the reduced nitrogen content were all rather independent of the nutrient supply. These findings are in contrast with those of P. lanceolata , a grassland species from a relatively nutrient-poor habitat, where both the activities of NR, GDH and GS and the reduced nitrogen content were correlated with the level of the nutrient supply. The rigidity of the nitrogen metabolism of P. major major may be of advantage if the nutrient supply is limited only for relatively short periods.     

The accumulation of Δ′-acetylornithine and other solutes in the salt marsh grass Puccinellia maritima

The salt marsh grass Puccinellia maritime was shown to accumulate several organic solutes when subject to low water potentials. These solutes include the non-protein amino acid Δ′-acetylornithine, the amide glutamine, the imino acid proline and soluble carbohydrates. The increase in organic solutes observed under saline conditions appears too large for all of them to be localized in the cytoplasm. It is suggested that solute synthesis may reduce the dependence of the plant on the absorption of sodium and chloride ions as sources of osmotically active solutes.     

Comparison between temperature-induced changes and effects caused by dark/light adaptation in the eyes of two species of Antarctic crustaceans

Summary The amphipod, Orchomene plebs, and the isopod, Glyptonotus antarcticus, both adapted to live in seawater of a temperature of-2° to 0° C, were kept for 7h at the unphysiologically high temperature of +10° C. Temperature elevation appeared to mimic light adaptation with regard to the position of the screening pigment granules within the visual cells, but not with respect to ultrastructural changes in the microvillar array of the rhabdom, i.e. the visual membranes. Cellular metabolism, membranous fatty acid composition, and ion fluxes, all known to be readily affected by an increase in temperature, are thought to be responsible for the observed effects. Pigment granules could possibly cause an elevation of intracellular temperatures due to the fact that they are dark and dissipate absorbed energy as heat.     

Rhabdom breakdown in the eye of Cirolana borealis (Crustacea) caused by exposure to daylight

Summary The effect of daylight on the compound eye was investigated in the deep-water crustacean isopod Cirolana borealis Lilljeborg. The animals were captured and fixed at night (dark-exposed, i.e. not exposed to light) and day (daylight-exposed), respectively. Changes in light and darkness have an effect on the retinula cells; the ultrastructure of dark-exposed eyes is characterized by well-preserved organelles and cytoplasm. The photoreceptor membranes covering the microvilli are regularly aligned, and the outline of the villi is smooth. Electron-dense pigment granules are evenly distributed in the cytoplasm of the retinula cell outside the rhabdom. Daylight-exposed eyes differ from the dark-exposed eyes in the following aspects: (i) the microvilli are disrupted, (ii) retinula-cell pigment is found in the rhabdom, and (iii) the cytoplasm of retinula cells is vesiculated. These results are interpreted as retinal damage caused by excess exposure to light.     

青桃利用单、复花芽结果对盛果期生长结实的影响

青桃盛果期,特别中庸偏旺的植株,单、复花芽果枝数大体均等,复花芽果枝以其复芽个体较大,枝条较粗而往往表现为优势。然而笔者于1974—1979年观察了青桃树以单、复花芽结果对盛果初期的影响,结果表明:利用单花芽结果,控制了强旺枝和结果部位,使果枝分布均匀,树势稳定,尤其果枝数、花芽数、单株产量等的变动趋势与年度增加无关,r为:-0.2899、0.0620(单、复花芽果枝数分别占总果枝数的35.1％和16.7％),-0.3830、-0.1804(单、复花芽朵数分别占总花芽朵数的44.5％和13.4％),0.4093(单株年产量为179.4公斤,从而延长了盛果期;利用复花芽结果却相反,促进树势极性生长,旺枝增强,果枝外移,内膛空虚,尤其果枝数、花芽数、单株产量等的变动趋势随年度增加而呈显著与极显著负相关,r为:-0.8938~(**)、-0.9818~(**)(单、复花芽果枝数分别占总果枝数的27.1％和21.1％),-0.953~(**)、-0.8908~(**)(单、复花芽朵数占总花芽朵数的35.3％和6.8％).-0.8853~(**)(单株产量较单花芽结果减产19.4％),从而明显缩短盛果期。     

Zum Feinbau der Ommatidien von Pteronemobius heydeni (Fisch.) (Orthoptera,Gryllidae)

Zusammenfassung Die Ommatidien der Sumpfgrille Pteronemobius wurden elektronenmikroskopisch untersucht. Der dioptrische Apparat besteht aus der cuticularen Linse, auf der zahlreiche Cornea-Nippel stehen, sowie dem Kristallkegel mit seinen Zellen, die auch noch beim adulten Tier Mitochondrien besitzen. Diese vier Zellen bilden insgesamt acht nach basal gerichtete Fortsätze, vier laterale und vier zentrale. Die lateralen, die auch bei anderen Insekten vorkommen, ziehen zwischen den Retinulazellen bis zur Basalmembran, an der sie enden. In ihrem proximalen, erweiterten Bereich nehmen die Fortsätze Kontakt miteinander auf. Hier enthalten sie außer den für den gesamten Verlauf typischen Mikrotubuli Pigment und feine Granula, die denen des Kegels gleichen.Die vier anderen, zentral gelegenen Fortsätze bilden gemeinsam den dünnen Spitzenausläufer der Kegelbasis. Er wird vom Rhabdom umhüllt und endet nach etwa 6 m.Sieben oder acht Retinulazellen bilden ein Rhabdom vom geschlossenen Typ. Zunächst umfassen vier dieser Zellen den Kegel, doch treten noch vor seinem basalen Ende drei weitere hinzu. Die beiden primären Pigmentzellen werden dabei peripherwärts abgedrängt. Die sekundären Pigmentzellen bilden keinen geschlossenen Zylinder um die Retinulazellen.

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The fine structure of the ommatidia of Pteronemobius heydeni (fisch.) (Orthoptera, Gryllidae)

Summary The ommatidia of the gryllid Pteronemobius have been examined electron microscopically. The dioptric apparatus consists of a cuticular lens on which numeral nipples insert and of the crystalline cone with its cells bearing mitochondria even in the adult. These four cells form altogether eight proximally directed processes, four lateral and four central ones. The lateral processes — as in other insects — extend from between the retinula cells to the basal membrane at which they terminate. In its proximal enlarged region they get into contact with each other. Besides those microtubuli typical for the total process they contain pigment and fine granules similar to those of the cone.The four remaining processes centrally situated form the thin pointed appendix of the cone basis being enveloped by the rhabdom and ending after about 6 m.Seven or eight retinula cells form a rhabdom of the closed type. Primarily there are four of these cells enclosing the cone, however, farther proximally they are joined by three more cells. Thus, the two primary pigment cells are forced away towards the periphery. The secondary pigment cells do not constitute a closed cylinder around the retinula cells.

Frl. A. Hennig bin ich für ihre technische Mitarbeit zu großem Dank verpflichtet.     

The optic neuropiles and chiasmata of Crustacea

Summary On the basis of ontogeny and adult morphology, an interpretation of the arrangement of optic neuropiles and fibre connexions of the Crustacean compound eye is presented. In the embryo of phyllopods and decapods, the ommatidia, the lamina ganglionaris, and the medulla externa are developed synchronously from a common medial proliferation zone. As this zone persists in all investigated adult Crustacea that possess compound eyes, such a derivation of the mentioned structures is taken to be universal within the group. The direction of growth of the lamina ganglionaris is parallel with the row of ommatidia, the growth direction of the medulla externa is perpendicular to it and parallel with the long axis of the eyestalk. This arrangement is more or less retained in most adult non-Malacostracan Crustacea, and the axons of fully developed neurons pierce the optic neuropiles and leave and enter on the neuropile side. As a result, there is no chiasma in the non-Malacostracan groups.The Malacostraca have an extra neuropile, the medulla interna, derived from the medulla terminalis. Chiasmata occur between the lamina ganglionaris and the medulla externa, and between the medulla externa and the medulla interna. This difference from the non-Malacostracans depends on the course of the fibres. Those coming from the lamina ganglionaris leave the lamina on the neuropile side and enter medulla externa between the cell bodies in the perikaryon layer of the medulla externa neurons and the neuropile of the medulla. The fibres from the medulla externa to the lamina come from T-shaped neurons and emanate from the perikaryon layer side, entering the lamina on its neuropile side. The fibre relations between the medulla externa and the medulla interna are similar. Thus in both cases, chiasmata are present from the beginning, but they become obvious when the medulla externa rotates through part of a circle.The directed growth of the optic neuropiles and the course of the fibre connexions are consequently crucial to the understanding of the topographic relations between the neuropiles. A pattern with short neurons connecting neighbouring optic neuropiles and long neurons connecting the medulla externa with the central nervous system is common to all crustaceans.In memoriam Bertil Hanström.This work has been supported by a grant from the Swedish Natural Science Research Council 2760-3, 99-35.     

miR-133b靶向抑制SGTB对oxLDL诱导的血管内皮细胞损伤的影响*

目的:探讨微小RNA-133b(miR-133b)靶向抑制富含谷氨酰胺三十四肽重复序列的小蛋白质分子(SGTB)对氧化低密度脂蛋白(oxLDL)诱导的血管内皮细胞损伤的影响。方法:采用100 μg/ml的oxLDL诱导人脐静脉血管内皮细胞(EVC-304)24 h构建血管内皮细胞损伤模型。将EVC-304细胞分为对照组、oxLDL组(oxLDL处理)、oxLDL+miR-NC组(转染20 nmol/L miR-NC+oxLDL处理)、oxLDL+miR-133b组(转染20 nmol/L miR-133b mimics+oxLDL处理)、oxLDL+si-NC组(转染20 nmol/L si-NC+oxLDL处理)、oxLDL+si-SGTB组(转染20 nmol/L si-SGTB+oxLDL处理)、oxLDL+miR-133b+pcDNA组(转染20 nmol/L si-SGTB和pcDNA+oxLDL处理)、oxLDL+miR-133b+pcDNA-SGTB组(转染20 nmol/L si-SGTB和pcDNA-SGTB处理)。实时荧光定量PCR(qRT-PCR)和蛋白质印记(Western blot)检测miR-133b和SGTB的表达水平;流式细胞术检测细胞凋亡;试剂盒检测丙二醛(MDA)含量、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)的活性;Western blot检测B细胞淋巴瘤/白血病-2(Bcl-2)和Bcl-2相关X蛋白(Bax)的表达水平。双荧光素酶报告基因实验和Western blot验证miR-133b对SGTB的靶向调控关系。结果:与对照组比较,oxLDL诱导后EVC-304细胞miR-133b、Bcl-2的表达水平显著降低(P＜0.05),SGTB、Bax的表达水平显著升高(P＜0.05),MDA含量和细胞凋亡率显著增加(P＜0.05),SOD和GSH-Px活性显著降低(P＜0.05)。过表达miR-133b或干扰SGTB均可抑制oxLDL诱导的EVC-304细胞凋亡和氧化应激损伤(P＜ 0.05)。miR-133b与SGTB直接结合,过表达miR-133b显著下调SGTB表达(P＜0.05),抑制miR-133b显著上调SGTB表达(P＜0.05)。过表达SGTB可逆转过表达miR-133b对oxLDL诱导的血管内皮细胞损伤的影响(P＜0.05)。结论:miR-133b通过靶向抑制SGTB的表达,可减轻oxLDL诱导的血管内皮细胞氧化应激损伤和细胞凋亡。     

Integrated transcript and metabolite profiling reveals coordination between biomass size and nitrogen metabolism in Arabidopsis F1 hybrids

Heterosis refers to the improved agronomic performance of F₁ hybrids relative to their parents. Although this phenomenon is widely employed to increase biomass, yield, and stress tolerance of plants, the underlying molecular mechanisms remain unclear. To dissect the metabolic fluctuations derived from genomic and/or environmental differences contributing to the improved biomass of F₁ hybrids relative to their parents, we optimized the growth condition for Arabidopsis thaliana F₁ hybrids and their parents. Modest but statistically significant increase in the biomass of F₁ hybrids was observed. Plant samples grown under the optimized condition were also utilized for integrated omics analysis to capture specific changes in the F₁ hybrids. Metabolite profiling of F₁ hybrids and parent plants was performed using gas chromatography-mass spectrometry. Among the detected 237 metabolites, 2-oxoglutarate (2-OG) and malate levels were lower and the level of aspartate was higher in the F₁ hybrids than in each parent. In addition, microarray analysis revealed that there were 44 up-regulated and 12 down-regulated genes with more than 1.5-fold changes in expression levels in the F₁ hybrid compared to each parent. Gene ontology (GO) analyses indicated that genes up-regulated in the F₁ hybrids were largely related to organic nitrogen (N) process. Quantitative PCR verified that glutamine synthetase 2 (AtGLN2) was upregulated in the F₁ hybrids, while other genes encoding enzymes in the GS-GOGAT cycle showed no significant differences between the hybrid and parent lines. These results suggested the existence of metabolic regulation that coordinates biomass and N metabolism involving AtGLN2 in F₁ hybrids.