Nine years of enriched CO₂ changes the function and structural diversity of soil microorganisms in a grassland     

D. Drissner    H. Blum    D. Tscherko  & E. Kandeler 《European Journal of Soil Science》2007,58(1):260-269

To gain insight into microbial function following increased atmospheric CO₂ concentration, we investigated the influence of 9 years of enriched CO₂ (600 μl litre⁻¹) on the function and structural diversity of soil microorganisms in a grassland ecosystem under free air carbon dioxide enrichment (FACE), as affected by plant species (Trifolium repens L. and Lolium perenne L. in monocultures and mixed culture) and nitrogen (N) supply. We measured biomass and activities of enzymes covering cycles of the most important elements (C, N and P). The microbial community was profiled by molecular techniques of phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analysis. The enrichment in CO₂ increased soil microbial biomass (+48.1%) as well as activities of invertase (+36.2%), xylanase (+22.9%), urease (+23.8%), protease (+40.2%) and alkaline phosphomonoesterase (+54.1%) in spring 2002. In autumn, the stimulation of microbial biomass was 25% less and that of enzymes 3–12% less than in spring. Strong correlations between activities of invertase, protease, urease and alkaline phosphomonoesterase and microbial biomass were found. The stimulation of microbial activity in the enriched atmosphere was probably caused by changes in the quantity and kind of root litter and rhizodeposition. The response of soil microorganisms to enriched CO₂ was most pronounced under Trifolium monoculture and under greater N supply. The PLFA analysis revealed that total PLFA contents were greater by 24.7% on average, whereby the proportion of bioindicators representative of Gram‐negative bacteria increased significantly in the enriched CO₂ under less N‐fertilized Lolium culture. Discriminant analysis showed marked differences between the PLFA profiles of the three plant communities. Shannon diversity indices calculated from DGGE patterns were greater (+12.5%) in the enriched CO₂, indicating increased soil bacterial diversity. We conclude that greater microbial biomass and enzyme activity buffer the potential increase in C sequestration occurring from greater C addition in enriched CO₂ due to greater mineralization of soil organic matter.  相似文献   

Ultralow calcium requirements of fungi facilitate use of calcium regulating agents to suppress host calcium-dependent defenses,synergizing infection by a mycoherbicide     

Gressel J  Michaeli D  Kampel V  Amsellem Z  Warshawsky A 《Journal of agricultural and food chemistry》2002,50(22):6353-6360

Infection by many fungi activates a variety of calcium dependent defenses in the hosts, slowing or suppressing the attacker and limiting the efficacy of mycoherbicides. The calcium requirement for fungal growth is so low that it could only be implied based on fungi containing calcium-dependent signaling enzymes. Analytical grade media contain <2 microM calcium, and the addition of specific chelators does not affect fungal growth. Hydrophobic derivatives of the calcium-specific chelator BAPTA designed to traverse plant cuticles were synthesized in order to chelate calcium internally during fungal attack. Some chelators as well as calcium precipitating oxalate and channel blocker verapamil were applied with a weakly mycoherbicidal Colletotrichum coccodes to cotyledons of compatible Abutilon threophrasti. They suppressed calcium dependent callose biosynthesis in the weed and increased virulence but may have affected other calcium-dependent processes that facilitate virulence. The low calcium requirement of fungi, and their high affinity for calcium, allows the application of calcium-regulating agents as synergists for mycoherbicides where the weed uses calcium-dependent defenses.  相似文献   

Anthropogenic Vanadium-Chromium-Iron and Cerium-Lanthanum-Iron Particles in Settled Urban House Dust: CCSEM Identification and Analysis     

Powell  J. W. D.  Hunt  A.  Abraham  J. L. 《Water, air, and soil pollution》2002,135(1-4):207-217

There is continuing concern over the health threat posed by theinhalation of ambient, transition-metal-containing particulatematter. Here, we report on the collection of two types ofanthropogenic, airborne particles, composed of iron with vanadiumand chromium (FeVCr) and iron with the rare earth metals ceriumand lanthanum (FeCeLa), respectively. Bi-weekly deposition platesamples were collected on indoor window sills of residentiallocations in inner-city Syracuse, NY. Sampling was continuous ateach location for two months during the spring of 1999. Themetal-bearing particles were identified, analyzed, and sizedin situ on each deposition plate using computer controlledscanning electron microscopy (CCSEM). Approximately 17% of thoseanalyzed by CCSEM fell into the inhalable size fraction. Particle loading varied between locations and changed over time.This was probably a function of various factors affectingparticle deposition rates. Notwithstanding, the plate loadingsfor the FeVCr-bearing particles tended to peak during the middleof the sampling period, suggesting that a single source/processwas operating to produce the FeVCr particles. The large sizeattained by some of these particles (greater than 50 μm inaggregates) suggest that long range transport was probably notinvolved.  相似文献   

Effects of elevated CO₂ concentration on rhizodeposition from Lolium perenne grown on soil exposed to 9 years of CO₂ enrichment     

S. Bazot  H. Blum  C. Robin 《Soil biology & biochemistry》2006,38(4):729-736

The effects of enriched CO₂ atmosphere on partitioning of recently assimilated carbon were investigated in a plant-soil-microorganism system in which Lolium perenne seedlings were planted into cores inserted into the resident soil within a sward that had been treated with elevated CO₂ for 9 consecutive years, under two N fertilisation levels (Swiss FACE experiment). The planted cores were excavated from the ambient (35 Pa pCO₂) and enriched (60 Pa pCO₂) rings at two dates, in spring and autumn, during the growing season. The cores were brought back to the laboratory for ¹⁴C labelling of shoots in order to trace the transfer of recently assimilated C both within the plant and to the soil and microbial biomass. At the spring sampling, high N supply stimulated shoot and total dry matter production. Consistently, high N enhanced the allocation of recently fixed C to shoots, and reduced it to belowground compartments. Elevated CO₂ had no consequences for DM or the pattern of C allocation. At the autumn sampling, at high N plot, yield of L. perenne was stimulated by elevated CO₂. Consistently, ¹⁴C was preferentially allocated aboveground and, consequently belowground recent C allocation was depressed and rhizodeposition reduced. At both experimental periods, total soil C content was similar in all treatments, providing no evidence for soil carbon sequestration in the Swiss Free Air CO₂ Enrichment experiment (FACE) after 9 years of enrichment. Recently assimilated C and soil C were mineralised faster in soils from enriched rings, suggesting a CO₂-induced shift in the microbial biomass characteristics (structure, diversity, activity) and/or in the quality of the root-released organic compounds.  相似文献   

Peste des petits ruminants in Ethiopian goats     

P. L. Roeder  G. Abraham  G. Kenfe  T. Barrett 《Tropical animal health and production》1994,26(2):69-73

Summary An outbreak of disease characterised by fever, ocular and nasal discharge, coughing and sneezing, oral necrosis, diarrhoea, enteritis and pneumonia in goats was shown by the use of specific cDNA probes to have been peste des petits ruminants, confirmed for the first time in Ethiopia. Both morbidity and mortality rates were high in goats but sheep were not affected.

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Peste De Pequeños Rumiantes En Caprinos En Etiopia

Resumen Se presentó por vez primera en Etiopía, un brote de peste de pequeños rumiantes, la que fue detectada mediante el uso de de sondas cADN especificas. La enfermedad se caracterizó por fiebre, descargas ocular y nasal, tos, estornudos necrosis oral, diarrea, enteritis y neumonia. Tanto la morbilidad como la mortalidad fueron altas en caprinos pero no en ovinos.

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Peste Des Petits Ruminants Chez Des Chevres Ethiopiennes

Résumé Une maladie caractérisée par de la fièvre, des écoulements nasal et oculaire, de la toux et des éternuements, une nécrose orale, de la diarrhée, de l'entérite et une pneumonie est apparue chez des chèvres. L'utilisation de sondes à ADNc spécifiques a montré qu'il s'agissait de la peste des petits ruminants, confirmée pour la première fois en Ethiopie. Les taux de morbidité étaient élevés chez les chèvres mais les moutons n'étaient pas affectés.

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Effects of nutrient restriction during the growing period on the performance of dwarf breeders     

B Leclercq  J C Blum 《World's poultry science journal》1971,27(3):288-289

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The Grain Quality of Landraces of Wheat as Compared with Modern Cultivars     

A. Blum    Bebi  Sinmena  G. Golan  J. Mayer 《Plant Breeding》1987,99(3):226-233

Landraces of tetraploid and hexaploid wheat from the Northern Negev in Israel were evaluated over two years for their grain quality attributes. Twenty-one populations of tetraploid wheat (Triticum durum, represented by 56 accessions) and 8 populations of hexaploid wheat (T. aestivum and T. compactum, represented by 13 accessions) were compared with 3 and 4 modern improved Israeli cultivars of tetraploid and hexaploid reheat, respectively. This comparison allowed to estimate the progress made in the improvement of gram quality m present-day cultivars. Except for grain protein content in the hexaploids, significant variation was revealed among landraces in kernel weight, protein content (tetraploids), sedimentation, mixograph score and carotin content. The best modern cultivars were comparable to the best landraces in kernel weight and carotin content (tetraploids), indicating that modern wheat breeding maximized kernel weight and carotin content, as compared with the tested landraces. Gram protein content and/or quality was not maximized in modern cultivars and its improvement was deemed possible by introgression from the best landraces in this respect.  相似文献   

Effects of dietary rhIGF-I in neonatal calves on the appearance of glucose, insulin, D-xylose, globulins and γ-glutamyl transferase in blood     

C. R. Baumrucker  M. H. Green  J. W. Blum 《Domestic animal endocrinology》1994,11(4):393-403

Cow colostrum is rich in insulin-like growth factors IGF-I and II, thus the dietary effects of recombinant human (rh) rhIGF-I on the newborn were of interest. The objective of this study was to examine the effects of dietary IGF-I upon selected blood components and gut absorptive development. Calves were blocked by birth weight and fed two times per d for a total of four times with the initial restricted diet. The initial feeding was 1.5 l and the remaining three feedings were at 2 1 with one of three experimental diets: 1) milk replacer plus isolated colostrum derived globulins (MR⁻), 2) same as 1 above plus 750 ng/ml rhIGF-I (MR⁺), 3) pooled cow colostrum (COL). Thereafter, all animals received only milk replacer at 5% of body weight (BW)/feeding two times per d with only treatment 2 having continued addition of 750 ng/ml rhIGF-I until experimental completion at 6 to 7 d after birth. At feeding three, animals were fed D-xylose (0.5 g/kg BW) and 5,000 U of bovine kidney membrane γ-glutamyl transferase as indicators of gut absorptive capacity. Colostrum-fed animals received 5,000 U of natural occurring γ-glutamyl transferase activity in the 1.5 l first feeding. Blood samples taken over time were collected and saved as frozen plasma. All diets were analyzed for nutrient composition and endogenous levels of test hormones. Colostrum fed calves had greater globulin concentration (P < 0.01) than MR⁻ or MR⁺ fed calves. Recombinant hIGF-I feeding had no effect (MR⁻ vs. MR⁺) upon total protein, albumin or globulin blood levels. Absorption of colostrum γ-glutamyl transferase at first feeding resulted in a peak total blood U of 4.5% of that fed. Although enzyme absorption was greatly reduced by the third feeding (0.5% of total fed), MR⁺ fed calves exhibited no significant difference in enzyme absorption when compared with the controls (MR⁻ vs. MR⁺). However, pharmacokinetic analysis of D-xylose absorption at the third feeding showed diet effect upon absorption of D-xylose. Dietary rhIGF-I may change development or activity of sugar transporters and also may alter absorption of macromolecules (closure) in neonatal calves.  相似文献   

Antisporulant action of fungicides against Podosphaera leucotricha on apple seedlings     

Abraham Sztejnberg  Robert J. W. Byrde  David Woodcock 《Pest management science》1975,6(2):107-111

A number of commercial fungicides and dinitrophenolic compounds were tested for their ability to suppress further sporulation of established infections of the apple mildew fungus Podosphaera leucotricha on seedlings in the greenhouse. Although they did not kill the fungus, two organophosphorus and two benzimidazole-type compounds gave powerful suppression for at least 18 days. Other fungicides known to control apple mildew in the field had a less marked effect. Sporulation occurred on subsequent untreated growth to the same extent as on control seedlings, except where either of two substituted dinitrophenols had been used.  相似文献   

Detection of the thyrostatic drug methylthiouracil (MTU) using high performance liquid chromatography (HPLC) and high performance thin layer chromatography in tissues and tissue extracts of fattening cattle     

J Blum  I Venzin  H Lutz 《Schweizer Archiv für Tierheilkunde》1986,128(8):419-424

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