Mycorrhiza in sedges—an overview

Most terrestrial plants associate with root-colonising mycorrhizal fungi, which improve the fitness of both the fungal and plant associates. However, exceptions exist both between and within plant families failing to associate with mycorrhizal fungi or in the incidence and the extent of mycotrophy, which may vary greatly. Sedges are important pioneers of disturbed habitats and often dominate vegetations like wetlands, and arctic and alpine vegetations, in which the mycorrhizal inoculum in the soil is often low or absent. In the past, sedges were often designated as non-mycorrhizal, though limited reports indicated the presence of mycorrhiza in certain species. However, studies since 1987 indicate widespread occurrence of mycorrhiza in sedges. Based on these studies, the family Cyperaceae is no longer a non-mycorrhizal family, but the mycorrhizal status of its members is greatly influenced by environmental conditions. Further, sedges appear to have several morphological adaptations to thrive in the absence of mycorrhizal association. Though mycorrhizal associations have been noted in many sedge species, the ecological role of this association is not well documented and no clear generalisation can be drawn. Similarly, the role of mycorrhizal fungi on sedge growth and nutrient uptake or non-nutritional benefits has yet to be fully ascertained. This paper reviews the current information available on the incidence of mycorrhiza in sedges and the possible reasons for low mycotrophy observed in this family.     

Die Mycorrhiza der Lebermoose mit besonderer Berücksichtigung der thallosen Formen

Ohne ZusammenfassungMit 27 Textabbildungen.     

Arbuscular Mycorrhiza–Specific Signaling in Rice Transcends the Common Symbiosis Signaling Pathway

Knowledge about signaling in arbuscular mycorrhizal (AM) symbioses is currently restricted to the common symbiosis (SYM) signaling pathway discovered in legumes. This pathway includes calcium as a second messenger and regulates both AM and rhizobial symbioses. Both monocotyledons and dicotyledons form symbiotic associations with AM fungi, and although they differ markedly in the organization of their root systems, the morphology of colonization is similar. To identify and dissect AM-specific signaling in rice (Oryza sativa), we developed molecular phenotyping tools based on gene expression patterns that monitor various steps of AM colonization. These tools were used to distinguish common SYM-dependent and -independent signaling by examining rice mutants of selected putative legume signaling orthologs predicted to be perturbed both upstream (CASTOR and POLLUX) and downstream (CCAMK and CYCLOPS) of the central, calcium-spiking signal. All four mutants displayed impaired AM interactions and altered AM-specific gene expression patterns, therefore demonstrating functional conservation of SYM signaling between distant plant species. In addition, differential gene expression patterns in the mutants provided evidence for AM-specific but SYM-independent signaling in rice and furthermore for unexpected deviations from the SYM pathway downstream of calcium spiking.     

Mycorrhiza analyses in New Zealand truffières reveal frequent but variable persistence of Tuber melanosporum in co-existence with other truffle species

This study compiles the results from an examination of mycorrhizae on root samples from Tuber melanosporum truffières in New Zealand. Samples were taken over 5 years from 328 trees in 43 truffières established with nursery-inoculated trees. Mycorrhizae were analysed using a combination of morphological and molecular techniques, focusing on the identification of Tuber species. Results show that 49% of the trees, and nearly 90% of the truffières, retained T. melanosporum mycorrhizae up to 21 years after planting. Tuber mycorrhizae with spiky cystidia were found on 26.9% of the tested trees: Tuber brumale (5.5%), Tuber maculatum (10.7%), and unidentified Tuber species (10.7%), and were detected in 67% of the truffières tested. T. brumale was found in 28% and T. maculatum in 35% of the truffières. In 56% of the truffières, T. melanosporum was found to occur with spiky Tuber species. The existence of T. brumale and T. maculatum in the same truffière was recorded only once. Forty-four percent of trees examined had Scleroderma-like (SCL) mycorrhizae and 50% of trees hosted other ectomycorrhizal species (OE). For all categories of mycorrhizal species examined, the variation between truffières was greater than variation within each truffière. Overall results indicate that Corylus avellana tends to be more receptive to mycorrhizae of Tuber species than Quercus robur but is not necessarily more productive. In productive truffières, Q. robur appears to host SCL mycorrhizae more often than C. avellana. This is the first study of its scale to analyse the mycorrhizal species associated with T. melanosporum truffières in the Southern Hemisphere.     

Use of Arbuscular Mycorrhiza and Organic Amendments to Enhance Growth of Macaranga peltata (Roxb.) Müll. Arg. in Iron Ore Mine Wastelands

Macaranga peltata (Roxb.) Mull. Arg. is a disturbance tolerant plant species with potential in mine wasteland reclamation. Our study aims at studying the phyto-extraction potential of M. peltata and determining plant-soil interaction factors effecting plant growth in iron ore mine spoils. Plants were grown in pure mine spoil and spoil amended with Farm Yard Manure (FYM) and Vermicompost (VC) along with arbuscular mycorrhizal (AM) species Rhizophagus irregularis. Pure and amended mine spoils were evaluated for nutrient status. Plant growth parameters and foliar nutrient contents were determined at the end of one year. FYM amendment in spoil significantly increased plant biomass compared to pure mine spoil and VC amended spoil. Foliar Fe accumulation was recorded highest (594.67μg/g) in pure spoil with no mortality but considerably affecting plant growth, thus proving to exhibit phyto-extraction potential. FYM and VC amendments reduced AM colonization (30.4% and 37% resp.) and plants showed a negative mycorrhizal dependency (–30.35 and –39.83 resp.). Soil pH and P levels and, foliar Fe accumulation are major factors determining plant growth in spoil. FYM amendment was found to be superior to VC as a spoil amendment for hastening plant growth and establishment in iron ore mine spoil     

Stat5及JAK-Stat5通路

信号转导与转录因子（Stats）家族是一个由7个成员组成的转录调控家族,其中Stat5由于在多种细胞因子刺激时均可起到重要作用而引起了广泛的关注。Stat5具有两种不同类型,即Stat5a和Stat5b,它们均可被多种细胞因子所激活,启动JAK-Stat5信号通路,从而调节相应基因的表达。在两种Stat5的激活中,特殊位点的丝氨酸和酪氨酸的磷酸化对Stat5的激活起重要的作用。对信号通路严格的控制对于生物体来说具有重要的意义,在JAK-Stat5信号通路中,以SOCS3为代表的SOCS家族对JAK-Stat5的负反馈调节具有重要作用。     

The 5′-Nor Aristeromycin Analogues of 5′-Deoxy-5′-Methylthioadenosine and 5′-Deoxy-5′-Thiophenyladenosine

To extend the potential of 5′-noraristeromycin (and its enantiomer) as potential antiviral candidates, the enantiomers of the carbocyclic 5′-nor derivatives of 5′-methylthio-5′-deoxyadenosine and 5′-phenylthio-5′-deoxyadenosine have been synthesized and evaluated. None of the compounds showed meaningful antiviral activity.     

5—H5与5—HT6受体

5－HT5受体又分为5－HT5A及5－HT5B两种亚型受体,5－HT5A受体主要存在于小脑,大脑皮层,海马等脑区,5－HT5B受体仅在海马CA1区,缰核,背侧缝际核发现,该受体与麦角胺（Ergo-tamine),5-羧基酰氨基色胺（5－Carboxamidotryptamine,5-CT),5-HT,美西麦角（Methysergide)等配体亲和力较大,可能与5－HT 1D受体有某种功能联系,5－HT6受体主要在纹状体,边缘脑和大脑皮层等脑区表达,这类受体与三环类抗精神病药及抗抑郁药有高亲和力反应,提示它参与某些精神疾病的发生与治疗。     

A bacteriophage-induced 5-methyldeoxycytidine 5′-monophosphate kinase

Bacteriophage XP-12-infected Xanthomonas oryzae have been found to be a source of a kinase preparation which converts m⁵dCMP to m⁵dCDP and then to m⁵dCTP using ATP as the phosphate donor. Optimal formation of the triphosphate required the presence of creatine phosphate and creatine kinase. In the presence of dGTP, dTTP and dATP, Escherichia coli DNA polymerase I and T4 DNA polymerase catalyzed the incorporation of m⁵dCTP into DNA just as efficiently as that of dCTP. Neither dTMP nor dCMP served as substrate for the m⁵dCMP monophosphate kinase. Analogous preparations from uninfected X. oryzae were unable to phosphorylate m⁵dCMP.     

Synthesis and potato tuber-inducing activity of methyl 5′,5′,5′-trifluorojasmonate

Methyl 5′,5′,5′-trifluorojasmonate was synthesized as an antimetabolic analogue of methyl jasmonate. It induced potato tuber formation more effectively than methyl jasmonate and inhibited the growth of rice seedlings and the germination of lettuce and radish seeds. These results suggest that epijasmonic acid itself has potato tuber-inducing activity and that the hydroxyl group of tuberonic acid is not necessary for this activity.     

MECHANISM OF INACTIVATION OF S-ADENOSYL-L-HOMOCYSTEINE HYDROLASE BY 5′-DEOXY-5′-S-ALLENYLTHIOADENOSINE AND 5′-DEOXY-5′-S-PROPYNYLTHIOADENOSINE

5′-Deoxy-5′-S-allenylthioadenosine 1 and 5′-deoxy-5′-S-propnylthioadenosine 2, derived from adenosine, were prepared. 1 and 2 caused irreversible inactivation of AdoHcy hydrolase. ESI mass spectra analysis of the inactivated enzyme demonstrated that 1 and 2 were type II “mechanism-based” inhibitors.     

Synthesis of 5′-Fluoro-5′-deoxy-and 5′-Amino-5′-Deoxytoyocamycin and Sangivamycin and Some Related Derivatives

Abstract

A series of 5′-substituted analogs of toyocamycin were prepared by condensation of silylated 4-amino-6-bromo-5-cyanopyrrolo[2,3-d]pyrimidine with protected 5-azido-5-deoxy- or 5-fluoro-5-deoxyribofuranose followed by debromination and deblocking. Alternatively, 5′-azido-5′-deoxytoyocamycin was prepared by azidation of toyocamycin. Conversion of the 5-nitrile function of the toyocamycin derivatives into a carboxamide or a thiocarboxamide gave the corresponding analogs of sangivamycin or thiosangivamycin while reduction of the 5′-azido-5′-deoxy nucleosides provided 5′-amino-5′-deoxy derivatives.     

怪兽猎人5

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5′-nucleotidase

Summary The distribution of 5-nucleotidase activity in rat liver shows a sexual dependence. In male liver the activity in the bile canalicular wall is most pronounced, whereas the activity at the sinusoidal border of the liver parenchymal cell is slightly more in the female rat. Castration and treatment with sex hormones change the distribution pattern. The greatest variations in enzyme activity are seen at the bile canalicular site of the liver cell. These changes are probably an expression of the altered functional state of the liver cell.     

5′-Nucleotidase

Summary The distribution of 5-nucleotidase in several tissues of rat and mouse has been investigated. The enzyme is greatly specific in dephosphorylating 5-nucleotides. Two 5-nucleotidases seem to exist: one showing greatest activity at pH 5.0, while the other is most active at pH 7.0–7.5. The localization of these two enzymes is not identical. At the acid pH the deoxyribonucleotides are dephosphorylated faster than the ribonucleotides, while at the neutral pH the ribonucleotides are hydrolysed more rapidly. In contrast to the non-specific phosphatases the nucleotidases can be stimulated by magnesium and manganese ions. The acid nucleotidase can be considered as a lysosomal enzyme. The neutral nucleotidase can be involved in transport processes in capillaries and sinusoids. Other localizations of the enzyme suggest a role of the enzyme in the catabolism of nucleic acids.     

5′-Nucleotidase

Summary To get more insight in the function of 5-nucleotidase catabolic and anabholic processes were investigated in which 5-nucleotides are involved. The catabolism of adenosine-5-monophosphate was studied by investigating the reaction products obtained after incubation of homogenates of several organs of rat and mouse with adenosine-5-monophosphate and with adenosine. Two experimental tumours of the mouse were investigated in the same way. It was found that in tissues containing a high activity of 5-nucleotidase other enzymes involved in the catabolism of 5-nucleotides, such as nucleosidase, adenosine deaminase and adenosine-5-monophosphate deaminase could also be demonstrated.The anabolic processes in which 5-nucleotides are involved had been studied by investigating the incorporation of tritium-labeled thymidine in several tissues of the mouse. It appeared that in cells showing a high 5-nucleotidase activity no incorporation of radioactive thymidine could be found, while in cells showing incorporation of thymidine enzyme activity could not be demonstrated.A discussion is given about the possible role of 5-nucleotidase in the control of nucleic acid biosynthesis and in the catabolism of nucleic acids.Abbreviations used DNA deoxyribonucleic acid - RNA ribonucleic acid - AMP Adenosine-5-monophosphate - ADP Adenosine-5-diphosphate - ATP Adenosine-5-triphosphate - IMP Inosine-5-monophosphate - GMP Guanosine-5-monophosphate - GDP Guanosine-5-diphosphate - GTP guanosine-5-triphosphate - CMP Cytidine-5-monophosphate - CDP Cytidine-5-diphosphate - CTP Cytidine-5-triphosphate - UMP Uridine-5-monophosphate - UDP Uridine-5-diphosphate - UTP Uridine-5-triphosphate - TMP Thymidine-5-monophosphate - TDP Thymidine-5-diphosphate - TTP Thymidine-5-triphosphate - Ado Adenosine - Ad Adenine - Ino Inosine - Hypox Hypoxanthine - Xanth Xanthine - Xantho Xanthosine - Guano Guanosine - Gua Guanine - Ura Uracil - U Uridine - Cyt Cytidine - Cyto Cytosine - Thym Thymidine The corresponding deoxy-compounds have been indicated with the prefix d for instance dCMP, deoxycytidine-5-monophosphate.