170,996 research outputs found
Diel variations in the carbon isotope composition of respired CO(2) and associated carbon sources: a review of dynamics and mechanisms
No full textWerner C, Gessler A. Diel variations in the carbon isotope composition of respired CO(2) and associated carbon sources: a review of dynamics and mechanisms. Biogeosciences. 2011;8(9):2437-2459.Recent advances have improved our methodological approaches and theoretical understanding of post-photosynthetic carbon isotope fractionation processes. Nevertheless we still lack a clear picture of the origin of short-term variability in delta(13)C of respired CO(2) (delta(13)C(res)) and organic carbon fractions on a diel basis. Closing this knowledge gap is essential for the application of stable isotope approaches for partitioning ecosystem respiration, tracing carbon flow through plants and ecosystems and disentangling key physiological processes in carbon metabolism of plants. In this review we examine the short-term dynamics in delta(13)C(res) and putative substrate pools at the plant, soil and ecosystem scales and discuss mechanisms, which might drive diel delta(13)C(res) dynamics at each scale. Maximum reported variation in diel delta(13)C(res) is 4.0, 5.4 and 14.8 parts per thousand in trunks, roots and leaves of different species and 12.5 and 8.1 parts per thousand at the soil and ecosystem scale in different biomes. Temporal variation in post-photosynthetic isotope fractionation related to changes in carbon allocation to different metabolic pathways is the most plausible mechanistic explanation for observed diel dynamics in delta(13)C(res). In addition, mixing of component fluxes with different temporal dynamics and isotopic compositions add to the delta(13)C(res) variation on the soil and ecosystem level. Understanding short-term variations in delta(13)C(res) is particularly important for ecosystem studies, since delta(13)C(res) contains information on the fate of respiratory substrates, and may, therefore, provide a non-intrusive way to identify changes in carbon allocation patterns
J. Gessler en C. Vanderstraeten. Algemeen Repertorium der Hasseltsche ordonnantieboeken.
No full textHansay Alfred. J. Gessler en C. Vanderstraeten. Algemeen Repertorium der Hasseltsche ordonnantieboeken.. In: Revue belge de philologie et d'histoire, tome 1, fasc. 2, 1922. p. 376
J. Gessler en C. Vanderstraeten. Algemeen Repertorium der Hasseltsche ordonnantieboeken.
No full textHansay Alfred. J. Gessler en C. Vanderstraeten. Algemeen Repertorium der Hasseltsche ordonnantieboeken.. In: Revue belge de philologie et d'histoire, tome 1, fasc. 2, 1922. p. 376
Epidemiology of Plasmopara viticola: field distribution of primary and secondary infections in the early stage of the season and microclimate impact on infection severity
No full textVf scab resistance of Malus
No full textThe apple production in temperate regions with spring rains, the Scab caused by the fungus Venturia inaequalis is the most important constraint. To produce spotless apples and avoid damage that develops during
storage, growers apply fungicide on a regular or weatherdetermined basis. All major apple cultivars are highly susceptible to this disease. To limit the need for fungicide applications, apple breeders are currently introgressing disease resistance from wild Malus accessions into commercial
lines. The first attempts to do this were made 100 years ago. As apples are self-incompatible, pseudobackcrossing is used to eliminate unwanted traits from wild Malus and select new cultivars that are attractive to both producers and consumers. This process, from the first cross of a commercial cultivar with a wild, disease-resistant Malus, is extremely long due to apple’s long juvenile phase, the need for more than seven backcross steps and the
high heterozygosity of this genus. Therefore, most of today’s scab-resistant cultivars rely on a single introduction
of scab resistance from Malus floribunda 821, referred to as Vf. In this paper, we trace the history of Vf from its initial
identification through its use in breeding and commercial production. We sum up the literature describing how and where Vf resistance has been overcome by new pathotypes of V. inaequalis. Finally, we describe the current knowledge of the genes behind Vf resistance, its mode of action and the use of Vf genes in gene technolog
Tonsils - Place of botulinum toxin production: Results of routine laboratory diagnosis in farm animals
No full textSince a case of a veterinarian was reported, who was likely to be infected/intoxicated by Clostridium botulinum during the handling of a diseased animal, tonsils in animals were tested for botulinum neurotoxin and bacterial forms of neurotoxic Clostridium botulinum during routine botulism laboratory examinations including standard samples (intestinal tract and liver) from 48 cattle, I I horses, and 14 goats. Ten out of 60 samples from tonsils contained free botulinum toxin, and 12 out of 59 were positive for live toxin producing bacteria. In 32 out of 162 intestinal samples toxin was detected. Toxin producing bacteria were found in 37 samples. Eight of 56 liver samples contained free toxin, and 15 out of 43 toxigenic bacteria. Samples from 10 slaughter pigs were all negative, whereas from slaughter cattle tonsils had a high incidence of toxin (7 of 10) or toxigenic bacteria (2 of 8). The results are discussed in the context of effects on animal health and botulism as zoonosis. (C) 2008 Elsevier B.V. All rights reserved
Assessment of Plasmopara viticola oospores germination by gene expression detection of a putative puf family member
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