Low levels of ferredoxin, ATP and leghemoglobin contribute to limited N2 fixation of peas (Pisum sativum L.) and alfalfa (Medicago sativa L.) under S deficiency conditions     

Heinrich W. Scherer  Svea Pacyna  Katrin R. Spoth  Margot Schulz 《Biology and Fertility of Soils》2008,44(7):909-916

Sulphur (S) has become a major limiting factor for plant production in industrial as well as in remote industrial rural areas. Limitation of S can reduce legume N₂ fixation by affecting nodule development and function. In pot experiments with pea (Pisum sativum L.) and alfalfa (Medicago sativa L.), we investigated the influence of S on growth, ferredoxin, ATP and leghemoglobin concentrations. Addition of 200 mg S pot⁻¹ increased yield of shoots, roots and nodules of both plant species significantly. However, the influence of S on nodule yield formation was most pronounced. Pea and alfalfa roots were found to have higher S concentrations than shoots and being up to 2.9 times the S concentration in the shoots of peas under S-sufficient conditions. Sulphur addition also increased N₂ fixation significantly. The ferredoxin concentration in bacteroids of root nodules of pea was increased significantly by S only 10 weeks after planting and in bacteroids of root nodules of alfalfa 10 and 17 weeks after planting, while on per pot base the amounts of ferredoxin were higher throughout the experimental period of time. The ATP concentration of bacteroids of root nodules of both plant species as well as of mitochondria of root nodules of pea were significantly higher with optimum S supply. The effects of S deficiency on N₂ fixation are likely to be caused by the shortage of ferredoxin and ATP. The amount of leghemoglobin was reduced in comparison to nodules of the S-sufficient plants.  相似文献   

Formation of alpha-dicarbonyl compounds in beer during storage of Pilsner     

Bravo A  Herrera JC  Scherer E  Ju-Nam Y  Rübsam H  Madrid J  Zufall C  Rangel-Aldao R 《Journal of agricultural and food chemistry》2008,56(11):4134-4144

With the aim of determining the formation of alpha-dicarbonyl intermediates during beer aging on the shelf, alpha-dicarbonyls were identified and quantified after derivatization with 1,2-diaminobenze to generate quinoxalines. The sensory effects of alpha-dicarbonyls were evaluated by the quantification of key Strecker aldehydes and by GC-olfactometry (GCO)analysis of beer headspace using solid phase microextraction. Four alpha-dicarbonyls, reported here for the first time, were detected in fresh and aged beers, three were derived from the 2,3-enolization pathway of mono- and disaccharides, and the fourth was derived from the epimerization of 3-deoxy-2-hexosulose. Ten alpha-dicarbonyls were quantified during beer processing and during different periods of beer aging at 28 degrees C. The aging periods were from 15 to 105 days. During beer aging, 1-deoxydiuloses were produced and degraded, while 1,4-dideoxydiuloses were produced at the highest rates. The GCO analysis indicated that forced beer aging increased the amounts of furaneol, trans-2-nonenal, and phenylacetaldehyde. The blockage of alpha-dicarbonyls inhibited the accumulation of sensory-active aldehydes in the beer headspace.  相似文献   

β-d-Glucosyl and O-malonyl-β-d-glucosyl conjugates of pentachlorophenol in soybean and wheat: Identification and enzymatic synthesis     

Rudolf Schmitt  Jürgen Kaul  Theo v.d. Trenck  Egmont Schaller  Heinrich Sandermann 《Pesticide biochemistry and physiology》1985,24(1):77-85

The polar metabolite fraction formed by soybean cell suspension cultures from [¹⁴C]pentachlorophenol (PCP) was fractionated by repeated high-performance liquid chromatography. The β-d-glucopyranosyl conjugate of PCP was identified by cochromatography, by chemical and enzymatic degradation, and by mass spectroscopic comparison with the authentic compound. The O-(malonyl)-β-d-glucopyranosyl conjugate of PCP was identified by chromatographic and electrophoretic comparison with the enzymatically synthesized compound, by specific chemical and enzymatic degradation, and by mass spectroscopy. Soluble protein extracts from both soybean and wheat cells catalyzed (a) the UDPG-dependent conversion of PCP to the β-d-glucopyranosyl conjugate, and (b) the malonyl-SCoA-dependent further conversion to the O-(malonyl)-β-d-glucopyranosyl conjugate. These enzymes were partially purified and had apparent molecular weights between 40,000 and 48,000. Free PCP was again released from the conjugates upon incubation with plant malonyl esterase and/or β-glucosidase preparations.  相似文献   

Effects of tebuconazole on morphology,structure, cell wall components and trichothecene production of Fusarium culmorum in vitro     

Zhensheng Kang  Lili Huang  Ulrich Krieg  Astrid Mauler‐Machnik  Heinrich Buchenauer 《Pest management science》2001,57(6):491-500

The effects of tebuconazole, a systemic fungicide, on the morphology, structure, cell wall components and toxin production of Fusarium culmorum were investigated in vitro. Treatment was by application of four filter paper strips (0.75 cm × 5.0 cm) soaked in 20 µg ml ^?1 fungicide placed around a point inoculum in Petri dishes. Mycelial growth was strongly inhibited by fungicide treatment. Scanning electron microscopic observations showed that the fungicide caused irregular swelling and excessive branching of hyphae. The morphological changes induced by the fungicide at the ultrastructural level included considerable thickening of the hyphal cell walls, excessive septation, the formation of the incomplete septa, extensive vacuolisation, accumulation of lipid bodies and progressing necrosis or degeneration of the hyphal cytoplasm. Non‐membrane inclusion bodies were often detected in the hyphal cytoplasm. Furthermore, the formation of new hyphae (daughter hyphae) inside collapsed hyphal cells was common following treatment. The daughter hyphae also displayed severe alterations such as irregular thickening of the cell walls and necrosis of the cytoplasm. Using cytochemical techniques, the labelling densities of chitin and β‐1,3‐glucan in the cell walls of the fungicide‐treated hyphae were more pronounced than in those of the control hyphae. Moreover, immunogold labelling with antiserum against deoxynivalenol (DON) revealed that Fusarium toxin DON was localized in the cell walls, cytoplasm, mitochondria and vacuoles of the hyphae from the control and the fungicide treatment, but the labelling density in the fungicide‐treated hyphae decreased dramatically compared with the control hyphae, indicating that tebuconazole reduced Fusarium toxin production of the fungus. © 2001 Society of Chemical Industry  相似文献   

Investigations of humoral and cellular regulation mechanisms of the redox-homeostasis in cattle from ecological farming--2. Influence of race and age on the enzymatic redox control in the blood plasma     

Prokopyuk T  Matthes HD  Pastushenko V  Heinrich H 《Berliner und Münchener tier?rztliche Wochenschrift》2002,115(5-6):195-199

The present study examined the effects of race and age on the redox potential behavior of blood plasma samples. The blood plasma from clinical healthy heifers (44) and calves (45) were investigated. The animals presented three different cattle races (Limousin, Angus and Hereford), grazed on pasture. The blood plasma test consists of two parts: analysis of the initial redoxpotential as well as the investigation of the action of biocatalists. ATP, ATP plus caffeine, GTP and FAD+ were used as an adding substances for the differential analysis. The influence of biocatalist on the redox balance and the reaction of the redox dependent enzymatic system of native plasma significant correlated with animal race and age.  相似文献   

Studies on the Infection Process of Fusarium Culmorum in Wheat Spikes: Degradation of Host Cell Wall Components and Localization of Trichothecene Toxins in Infected Tissue     

Z. Kang  H. Buchenauer 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(7):653-660

After single spikelet inoculation, the infection process of Fusarium culmorum and spread of fungal hyphae in the spike tissues were studied by scanning and transmission electron microscopy. While hyphal growth on outer surfaces of the spike was scanty and no successful penetration was observed, the fungus developed a dense mycelium on the inner surfaces and effectively invaded the lemma, glume, palea and ovary by penetration pegs. During the inter- and intracellular spreading of the fungus, marked alterations in the host tissues were observed, including degeneration of cytoplasm, cell organelles, and depositions of electron dense material between cell wall and plasmalemma. Ultrastructural studies revealed that host cell walls in proximity of the penetration peg and in contact with hyphae were less dense or transparent which suggested that cell wall degrading enzymes were involved in colonisation of host tissues by fungal hyphae. Enzyme- and immunogold-labelling investigations confirmed involvement of extracellular enzymes, that is cellulases, xylanases and pectinases, in degradation of cell wall components. Localization studies of trichothecenes indicated that toxins could be detected in host tissues at an early stage of infection.  相似文献   

Differences in light stability of some carboxylic acid anilide fungicides in relation to their applicability for seed and foliar treatment     

Heinrich Buchenauer 《Pest management science》1975,6(5):525-535

Irradiation of carboxin, furcarbanil, pyracarbolid, cyclafuramid, benodanil, mebenil and oxycarboxin by u.v. light (254 nm) for 4 h resulted in 97, 64, 58, 50, 20, 18 and 15% inactivation, respectively. Photoinactivation of the different compounds in aqueous solution or in the solid state was much slower in sunlight than in u.v. light and stability increased in the following order: carboxin < furcarbanil ≤ cyclafuramid ≤ pyracarbolid < mebenil ≤ benodanil < oxycarboxin. The residues of carboxin and furcarbanil on the leaf surface of bean plants were almost completely inactivated after 40 h exposure to sunlight; cyclafuramid lost 85% of its activity. The toxicity of leaf deposits of pyracarbolid, mebenil, benodanil and oxycarboxin decreased by 83, 53, 50 and 41%, respectively after 80 h in sunlight. The compounds with low photostability (e.g. carboxin, furcarbanil and cyclafuramid) are recommended mainly for controlling seed- and soil-borne fungi; pyracarbolid, mebenil, oxycarboxin and benodanil, which proved to be more photostable, appear to be useful fungicides to control rust diseases. Among several photochemical decomposition products of carboxin detected, the sulphoxide and sulphone were identified.  相似文献   

Histochemical studies on the accumulation of reactive oxygen species (O₂ and H₂O₂) in the incompatible and compatible interaction of wheat—Puccinia striiformis f. sp. tritici     

Chen-Fang Wang  Li-Li Huang  Heinrich Buchenauer  Qing-Mei Han  Hong-Chang Zhang  Zhen-Sheng Kang   《Physiological and Molecular Plant Pathology》2007,71(4-6):230-239

The generation and accumulation of reactive oxygen species (ROS), superoxide anion (O₂⁻) and hydrogen peroxide (H₂O₂), were studied in the interaction between wheat cv. ‘Suwon 11’ and two races of Puccinia striiformis f. sp. tritici (avirulent and virulent). Generation of O₂⁻ and H₂O₂ was analyzed histochemically using nitroblue tetrazolium (NBT) and 3,3-diamino-benzidine (DAB), respectively. At the pre-penetration stage during appressorium formation both stripe rust races induced H₂O₂ accumulation in guard cells. In the incompatible interaction, a rapid increase of O₂⁻ and H₂O₂ generation at infection sites was detected. The percentage of infection sites showing NBT and DAB staining was 36.1% and 40.0%, respectively, 12 h after inoculation (hai). At extended incubation time until 24 hai, percentage of infection sites showing H₂O₂ accumulation further increased, whereas those exhibiting O₂⁻ accumulation declined. The early infection stage from 12 to 24 hai coincided with primary haustoria formation in mesophyll cells. In contrast, in the compatible interaction, O₂⁻ and H₂O₂ generation could not be detected in most of the infection sites. In the incompatible interaction, intensive DAB staining was also determined in mesophyll cells, especially in cell walls, surrounding the infected cells 16–24 hai; thereafter, these cells contained fluorescing compounds and underwent hypersensitive response (HR). The number of necrotic host cells surrounding the infection sites increased continuously from 20 to 96 hai. It might be concluded that H₂O₂ accumulation during the early infection stage is associated with the occurrence of hypersensitive cell death and that resistance response is leading to arrest the avirulent race of the obligate stripe rust pathogen. In the compatible interaction at 96 hai, H₂O₂ accumulation was observed in mesophyll cells surrounding the rust lesion.  相似文献   

Effectiveness and side effects of glue-traps to decrease damages caused by Byturus tomentosus in raspberry     

Andi Schmid  Heinrich Hoehn  Karin Schmid  Franco Weibel  Claudia Daniel 《Journal of pest science》2006,79(3):137-142

Damages caused by the larvae of Byturus tomentosus (Coleoptera: Byturidae) are a big problem of European raspberry production. Under integrated pest management conditions in Switzerland, B. tomentosus is controlled by chemical-synthetic insecticides. In organic production, no corresponding insecticides are permitted. White sticky traps (type Rebell^® bianco) are used for monitoring purposes. Can glue-traps also be used for mass-trapping and damage control? In this study, the attractiveness for adult B. tomentosus of one yellow and several white glue-traps was compared by counting the trapped individuals. Trapped beneficial insects like honey bees, Coccinellidae, Syrphidae and Chrysopidae were also counted. The contamination of the traps caused by other non-target arthropods was measured by a computer-assisted method. The white sticky trap type Rebell bianco was the most attractive for B. tomentosus. The attractiveness for the beneficials was relatively low, except when too much glue was applied on the traps, then the attractiveness for honey bees increased significantly. In this study, traps, which were placed in high densities (17 traps per 100 m²), significantly decreased the damages caused by larvae by around 40%. The trapping method does not cause any residuals of pesticides on the fruits or soil. Therefore, the trapping method could be an alternative to control B. tomentosus, especially in organic production.  相似文献   

Studies on the mechanisms of fixation and release of ammonium in paddy soils after flooding. I. Effect of iron oxides on ammonium fixation     

Heinrich W. Scherer  Yongsong Zhang 《植物养料与土壤学杂志》1999,162(6):593-597

Experiments were conducted with two typical paddy soils from China and a vermiculite to study the influence of iron oxides on the fixation and release of ammonium. Removing iron oxides, especially amorphous iron oxides, from the soils favoured the release of non-exchangeable NH₄-N and stimulated the fixation of NH₄-N in the presence of added (NH₄)₂SO₄. Addition of artificial goethite and hematite to the original soils or to the soils free of iron oxides reduced the fixation of NH₄⁺-ions. This effect was also observed with vermiculite. We conclude that the coating of clay minerals with iron oxides has an impact on the diffusion of NH₄⁺-ions into and out of the interlayers of the clay minerals. The reduction and dissolution of iron oxides induced by low redox potential (E_h) after flooding of paddy soils is assumed to be an important mechanism controlling NH₄⁺-fixation in paddy fields.  相似文献