Effect of extractives on vibrational properties of African Padauk (<Emphasis Type="Italic">Pterocarpus soyauxii</Emphasis> Taub.)     

Iris Brémaud  Nadine Amusant  Kazuya Minato  Joseph Gril  Bernard Thibaut 《Wood Science and Technology》2011,45(3):461-472

Extractives can affect the vibrational properties tanδ (damping coefficient) and E′/ρ (specific Young’s modulus), but this is highly dependent on species, compounds, and cellular locations. This paper investigates such effects for African Padauk (Pterocarpus soyauxii Taub.), a tropical hardwood with high extractives content and a preferred material for xylophones. Five groups of 26 heartwood specimens with large, yet comparable, ranges in vibrational properties were extracted in different solvents. Changes in vibrational properties were set against yields of extracts and evaluation of their cellular location. Methanol (ME) reached most of the compounds (13%), located about half in lumen and half in cell-wall. Water solubility was extremely low. tanδ and E′/ρ were very strongly related (R ² ≥ 0.93), but native wood had abnormally low values of tanδ, while extraction shifted this relation towards higher tanδ values. ME extracted heartwood became in agreement with the average of many species, and close to sapwood. Extractions increased tanδ as much as 60%, irrespective of minute moisture changes or initial properties. Apparent E′/ρ was barely changed (+2% to −4%) but, after correcting the mass contribution of extracts, it was in fact slightly reduced (down to −10% for high E′/ρ), and increasingly so for specimens with low initial values of E′/ρ.  相似文献   

Heterogeneous atmospheric aerosol production by acid-catalyzed particle-phase reactions   总被引：3，自引：0，他引：3  

Jang M  Czoschke NM  Lee S  Kamens RM 《Science (New York, N.Y.)》2002,298(5594):814-817

According to evidence from our laboratory, acidic surfaces on atmospheric aerosols lead to potentially multifold increases in secondary organic aerosol (SOA) mass. Experimental observations using a multichannel flow reactor, Teflon (polytetrafluoroethylene) film bag batch reactors, and outdoor Teflon-film smog chambers strongly confirm that inorganic acids, such as sulfuric acid, catalyze particle-phase heterogeneous reactions of atmospheric organic carbonyl species. The net result is a large increase in SOA mass and stabilized organic layers as particles age. If acid-catalyzed heterogeneous reactions of SOA products are included in current models, the predicted SOA formation will be much greater and could have a much larger impact on climate forcing effects than we now predict.  相似文献   

Non-invasive methods for studying working dog physiology in the field     

Nadine Gerth  J. Matthias Starck 《Journal of Veterinary Behavior: Clinical Applications and Research》2009,4(2):76-77

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Patterns of Outdoor Recreational Injury in Northern British Columbia     

Floyd A. Besserer  Nadine R. Caron 《The Forestry Chronicle》2013,24(4):397-401

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Mining Indonesian Microbial Biodiversity for Novel Natural Compounds by a Combined Genome Mining and Molecular Networking Approach     

Ira Handayani  Hamada Saad  Shanti Ratnakomala  Puspita Lisdiyanti  Wien Kusharyoto  Janina Krause  Andreas Kulik  Wolfgang Wohlleben  Saefuddin Aziz  Harald Gross  Athina Gavriilidou  Nadine Ziemert  Yvonne Mast 《Marine drugs》2021,19(6)

Indonesia is one of the most biodiverse countries in the world and a promising resource for novel natural compound producers. Actinomycetes produce about two thirds of all clinically used antibiotics. Thus, exploiting Indonesia’s microbial diversity for actinomycetes may lead to the discovery of novel antibiotics. A total of 422 actinomycete strains were isolated from three different unique areas in Indonesia and tested for their antimicrobial activity. Nine potent bioactive strains were prioritized for further drug screening approaches. The nine strains were cultivated in different solid and liquid media, and a combination of genome mining analysis and mass spectrometry (MS)-based molecular networking was employed to identify potential novel compounds. By correlating secondary metabolite gene cluster data with MS-based molecular networking results, we identified several gene cluster-encoded biosynthetic products from the nine strains, including naphthyridinomycin, amicetin, echinomycin, tirandamycin, antimycin, and desferrioxamine B. Moreover, 16 putative ion clusters and numerous gene clusters were detected that could not be associated with any known compound, indicating that the strains can produce novel secondary metabolites. Our results demonstrate that sampling of actinomycetes from unique and biodiversity-rich habitats, such as Indonesia, along with a combination of gene cluster networking and molecular networking approaches, accelerates natural product identification.  相似文献   

Combining permanent aerobiological networks and molecular analyses for large-scale surveillance of forest fungal pathogens: A proof-of-concept     

Jaime Aguayo  Claude Husson  Emilie Chancerel  Olivier Fabreguettes  Anne Chandelier  Céline Fourrier-Jeandel  Nadine Dupuy  Cyril Dutech  Renaud Ioos  Cécile Robin  Michel Thibaudon  Benoit Marçais  Marie-Laure Desprez-Loustau 《Plant pathology》2021,70(1):181-194

Forest disease management relies principally on a preventive approach in which epidemiological surveillance plays a crucial role. However, efficient and cost-effective surveillance methods are not currently available for large spatial scales. Nevertheless, aerobiological networks have been set up for several decades in many countries to monitor pollen dispersal and provide real-time assessments of allergenic risk. Here, we suggest that the same approach could be used for the surveillance of forest pathogens. Using molecular methods, we analysed samples from 12 sites of the French aerobiological network, at different dates. Both metabarcoding by high-throughput sequencing (using two markers and two different bioinformatics approaches) and real-time PCR targeting eight important forest pathogens were conducted. To validate the approach, temporal and spatial trends of spore detection were compared with field disease data. The metabarcoding approach demonstrated that many fungal plant pathogens could be found in aerobiological samples. Moreover, five of the eight targeted forest pathogens were detected by real-time PCR, with temporal and spatial trends of spore capture consistent with field data. In particular, Hymenoscyphus fraxineus was detected at high frequency in aerobiological samples in the areas where ash dieback has been present for the longest period of time, and at lower frequency in areas with more recent invasion. Spore detection of seasonal pathogens showed a temporal pattern similar to that of disease reports. Overall, our study provides a proof of concept that permanent aerobiological networks combined with molecular methods may provide a useful tool for large-scale surveillance of forest pathogens.  相似文献   

Genetic Diversity of Pathogenic and Nonpathogenic Populations of Fusarium oxysporum Isolated from Carnation Fields in Argentina     

Lori G  Edel-Hermann V  Gautheron N  Alabouvette C 《Phytopathology》2004,94(6):661-668

ABSTRACT In order to elucidate the origin of Fusarium oxysporum f. sp. dianthi in Argentina, the genetic diversity among pathogenic isolates together with co-occurring nonpathogenic isolates on carnation was investigated. In all, 151 isolates of F. oxysporum were obtained from soils and carnation plants from several horticultural farms in Argentina. The isolates were characterized using vegetative compatibility group (VCG), intergenic spacer (IGS) typing, and pathogenicity tests on carnation. Seven reference strains of F. oxysporum f. sp. dianthi also were analyzed and assigned to six different IGS types and six VCGs. Twenty-two Argentinean isolates were pathogenic on carnation, had the same IGS type (50), and belonged to a single VCG (0021). The 129 remaining isolates were nonpathogenic on carnation and sorted into 23 IGS types and 97 VCGs. The same VCG never occurred in different IGS types. Our results suggest that the pathogen did not originate in the local populations of F. oxysporum but, rather, that it was introduced into Argentina. Given the genetic homogeneity within Argentinean isolates of F. oxysporum f. sp. dianthi, either IGS type or VCG can be used for the identification of the forma specialis dianthi currently in Argentina.  相似文献   

Volatile flavor constituents of fruits from Southern Africa: Mobola plum (Parinari curatellifolia)     

Joulain D  Casazza A  Laurent R  Portier D  Guillamon N  Pandya R  Le M  Viljoen A 《Journal of agricultural and food chemistry》2004,52(8):2322-2325

The volatile flavor components of Mobola plum (Parinari curatellifolia), a native fruit of Southern Africa, have been isolated by a vacuum headspace concentration method. The concentrate was analyzed by hyphenated gas chromatographic techniques, including gas chromatography (GC)/mass spectrometry (MS) and GC/Fourier transform infrared (FTIR), together with other GC-coupled detection devices for the specific and selective detection of nitrogen- and sulfur-containing compounds. A total of 88 components were identified. Of these compounds, 12 contain nitrogen, including 2-aminobenzaldehyde and phenylacetaldoxime, which are detected for the first time in an edible fruit. In addition, two unusual nitrated compounds have been identified, including optically active (2-nitrobutyl)benzene, which is a new natural product. Quantitative and sensory data of the new compounds are provided.  相似文献   

Efficacy of Borrelia burgdorferi vaccine in dogs in North America: A systematic review and meta‐analysis     

Nadine A. Vogt  Jan M. Sargeant  Melissa C. MacKinnon  Ali M. Versluis 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2019,33(1):23-36

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Effect of vitamin E supplementation in milk replacer and Shiga toxoid vaccination on serum α‐tocopherol,performance, haematology and blood chemistry in male Holstein calves          下载免费PDF全文

Nadine Schmidt  Tim Luhmann  Liane Hüther  Ulrich Meyer  Stefanie A. Barth  Christian Menge  Jana Frahm  Sven Dänicke 《Journal of animal physiology and animal nutrition》2018,102(5):1167-1180

Vitamin E (vit E), an essential antioxidant for maintaining the stability of biological membranes and the function of the immune system, is considered to support adaptive immune responses and performance in cattle. The principal virulence factor of Shiga toxin (Stx)‐producing Escherichia coli (STEC), the eponymous Stx, modulates cellular immune responses in cattle, the primary STEC reservoir. Active and passive immunization of calves with Shiga toxoids (rStx_MUT) was recently shown to reduce the STEC shedding. Here, we examined the influence of vit E on calves' serum α‐tocopherol, performance, haematology, blood chemistry and its interaction with rStx_MUT immunization. Data from calves having received passive (colostrum from immunized cows) and active (intramuscularly at 5th and 8th weeks of life) vaccination with rStx_MUT (n = 24) were compared to unvaccinated controls (n = 24; fed with low anti‐Stx colostrum, placebo injected). For each vaccination group, data were analysed according to the level of vit E supplementation offered by milk replacer (188 IU all‐rac‐α‐tocopheryl acetate daily [VitE_M] vs. 354 IU [VitE_H]). An increase by 79% in daily vit E supplementation led to slightly higher serum α‐tocopherol level and earlier concentrate intake at the beginning of the experiment without significant differences in live weight gain, haematology, blood chemistry parameters and peripheral CD4⁺ and CD8⁺ T‐cell subpopulations. rStx_MUT vaccination modulated the CD4⁺/CD8⁺ ratio irrespective of vit E supplementation but decreased concentrate intake in VitE_H in a time‐dependent manner. Results of our study indicate that an increase in daily vit E supplementation vastly fails to exert effects on laboratory parameters and growth performance. However, observed interactive effects of vit E supply and vaccination on the regulation of feed intake deserves further attention.  相似文献