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91.
Rosana F Vieira Clia M
M
S Silva Aline H
N Maia Elisabeth F Fay Ktia C Coelho 《Pest management science》2000,56(5):431-440
An experiment was carried out in a greenhouse with the aim of determining an acceptable method to quantify the fungal population in a soil treated with the fungicide chlorothalonil. Doses of the fungicide ranging from 12 to 96 µg AI g−1 soil were applied and microbial biomass carbon (C), soil ergosterol content, living hyphal length, as well as counts of total and cellulolytic fungi colonies, were measured 1, 2, 3, 4 and 5 weeks after application. At the end of 16 weeks a new evaluation was done using the three first methods. The microbial biomass C was the least sensitive parameter and, on balance, the living hyphal length was the most sensitive parameter for demonstrating effects of chlorothalonil on the fungal population. Some problems related to the efficiency of the ergosterol content and living hyphal length measurements in the evaluation of the effect of the fungicide on the fungal microflora are discussed, as is the need to compare short‐term (0–5 weeks after treatment) with longer‐term (16 weeks) results. © 2000 Society of Chemical Industry 相似文献
92.
Differential effects of domoic acid and E. coli lipopolysaccharide on tumor necrosis factor-alpha, transforming growth factor-beta1 and matrix metalloproteinase-9 release by rat neonatal microglia: evaluation of the direct activation hypothesis
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Mayer AM Guzman M Peksa R Hall M Fay MJ Jacobson PB Romanic AM Gunasekera SP 《Marine drugs》2007,5(3):113-135
The excitatory amino acid domoic acid is the causative agent of amnesic shellfish poisoning in humans. The in vitro effects of domoic acid on rat neonatal brain microglia were compared with E. coli lipopolysaccharide (LPS), a known activator of microglia mediator release over a 4 to 24 hour observation period. LPS [3 ng/mL] but not domoic acid [1 mM] stimulated a statistically significant increase in TNF-alpha mRNA and protein generation. Furthermore, both LPS and domoic acid did not significantly affect TGF-beta1 gene expression and protein release. Finally, an in vitro exposure of microglia to LPS resulted in statistically significant MMP-9 expression and release, thus extending and confirming our previous observations. However, in contrast, no statistically significant increase in MMP-9 expression and release was observed after domoic acid treatment. Taken together our observations do not support the hypothesis that a short term (4 to 24 hours) in vitro exposure to domoic acid, at a concentration toxic to neuronal cells, activates rat neonatal microglia and the concomitant release of the pro-inflammatory mediators tumor necrosis factor-alpha (TNF-alpha) and matrix metalloproteinases-9 (MMP-9), as well as the anti-inflammatory cytokine transforming growth factor beta1 (TGF-beta1). 相似文献
93.
Ana Juan Michael F. Fay Julio Pastor Rocío Juan Inmaculada Fernández Manuel B. Crespo 《European Journal of Forest Research》2012,131(3):845-856
The Spanish populations of Juniperus oxycedrus subsp. macrocarpa are restricted to coastal dune habitats of the Mediterranean and Atlantic coasts. Here, we investigate the genetic structure
in this taxon and the possible existence of detailed phylogeographic structure associated with the Strait of Gibraltar using
data from amplified fragment length polymorphism (AFLP) and plastid markers for 14 populations in three regions: Andalusia,
the Valencian Community and the Balearic Islands. Principal coordinate analysis (PCOA) data revealed a lack of clear genetic
structure in J. oxycedrus subsp. macrocarpa based on AFLP. The highest AFLP genetic diversity was found in Andalusia. Plastid markers revealed 14 haplotypes, only two
of them were shared among the regions. Andalusian populations had the highest number of exclusive haplotypes. Our results
support Andalusia as a reservoir of genetic diversity for J. oxycedrus subsp. macrocarpa, and, as for other gymnosperms, this area could be considered as a genetic refugium. The frequent presence of common and
exclusive haplotypes in Andalusia might indicate the colonisation of the Spanish Mediterranean coast from the Atlantic populations.
Colonisation of these new areas could be promoted by biological factors, such as the existence of long-lived individuals or
potential for seed dispersal. Finally, the Strait of Gibraltar did not constitute a natural barrier to the expansion of this
species along the coast, as identical haplotypes are found on the Atlantic and Mediterranean coasts. 相似文献
94.
VL Grillo KE Arzey PM Hansbro AC Hurt S Warner J Bergfeld GW Burgess B Cookson CJ Dickason M Ferenczi T Hollingsworth MDA Hoque RB Jackson M Klaassen PD Kirkland NY Kung S Lisovski MA O'Dea K O'Riley D Roshier LF Skerratt JP Tracey X Wang R Woods L Post 《Australian veterinary journal》2015,93(11):387-393
95.
Rainfall variability,carbon cycling,and plant species diversity in a mesic grassland 总被引:7,自引:0,他引:7
Knapp AK Fay PA Blair JM Collins SL Smith MD Carlisle JD Harper CW Danner BT Lett MS McCarron JK 《Science (New York, N.Y.)》2002,298(5601):2202-2205
Ecosystem responses to increased variability in rainfall, a prediction of general circulation models, were assessed in native grassland by reducing storm frequency and increasing rainfall quantity per storm during a 4-year experiment. More extreme rainfall patterns, without concurrent changes in total rainfall quantity, increased temporal variability in soil moisture and plant species diversity. However, carbon cycling processes such as soil CO2 flux, CO2 uptake by the dominant grasses, and aboveground net primary productivity (ANPP) were reduced, and ANPP was more responsive to soil moisture variability than to mean soil water content. Our results show that projected increases in rainfall variability can rapidly alter key carbon cycling processes and plant community composition, independent of changes in total precipitation. 相似文献
96.
Sun H Ringdahl U Homeister JW Fay WP Engleberg NC Yang AY Rozek LS Wang X Sjöbring U Ginsburg D 《Science (New York, N.Y.)》2004,305(5688):1283-1286
Group A streptococci, a common human pathogen, secrete streptokinase, which activates the host's blood clot-dissolving protein, plasminogen. Streptokinase is highly specific for human plasminogen, exhibiting little or no activity against other mammalian species, including mouse. Here, a transgene expressing human plasminogen markedly increased mortality in mice infected with streptococci, and this susceptibility was dependent on bacterial streptokinase expression. Thus, streptokinase is a key pathogenicity factor and the primary determinant of host species specificity for group A streptococcal infection. In addition, local fibrin clot formation may be implicated in host defense against microbial pathogens. 相似文献
97.
Calcium gradients underlying polarization and chemotaxis of eosinophils 总被引:20,自引:0,他引:20
The concentration of intracellular free calcium ([Ca2+]i) in polarized eosinophils was imaged during chemotaxis by monitoring fluorescence of the calcium-sensitive dye Fura-2 with a modified digital imaging microscope. Chemotactic stimuli caused [Ca2+]i to increase in a nonuniform manner that was related to cell activity. In cells moving persistently in one direction, [Ca2+]i was highest at the rear and lowest at the front of the cell. Before cells turned, [Ca2+]i transiently increased. The region of the cell that became the new leading edge had the lowest [Ca2+]i. These changes in [Ca2+]i provide a basis for understanding the organization and local activity of cytoskeletal proteins thought to underlie the directed migration of many cells. 相似文献
98.
Kurniadi T Bel Rhlid R Fay LB Juillerat MA Berger RG 《Journal of agricultural and food chemistry》2003,51(10):3103-3107
Twenty-five acyloins were generated by biotransformation of aliphatic aldehydes and 2-ketocarboxylic acids using whole cells of baker's yeast as catalyst. Six of these acyloins were synthesized and tentatively characterized for the first time. Subsequent chemical reaction with 1,2-propanediamine under mild conditions resulted in the formation of thirteen 5,6-dihydropyrazines and six tetrahydropyrazines. Their odor qualities were evaluated, and their odor thresholds were estimated. Among these pyrazine derivatives, 2-ethyl-3,5-dimethyl-5,6-dihydropyrazine (roasted, nutty, 0.002 ng/L air), 2,3-diethyl-5-methyl-5,6-dihydropyrazine (roasted, 0.004 ng/L air), and 2-ethyl-3,5-dimethyltetrahydropyrazine (bread crustlike, 1.9 ng/L air) were the most intensive-smelling aroma active compounds. 相似文献
99.
Summary Populations of 59 Trifolium taxa were screened for condensed tannin content using the vanillin-HC1 test. Eight species (T. arvense, T. aureum, T. badium, T. campestre, T. dubium, T. micranthum, T. patens and T. spadiceum) were shown to contain tannins. These species are all found in Section Chronosemium or Section Trifolium Subsection Arvensia of the genus, and thus presence of tannins appears to have a taxonomic significance. Screening populations within species showed differences in tannin content, but no plants in these species were free of tannins. 相似文献
100.
Cristina?InocencioEmail author Robyn?S.?Cowan Francisco?Alcaraz Diego?Rivera Mike?F.?Fay 《Genetic Resources and Crop Evolution》2005,52(2):137-144
A genetic fingerprinting technique (AFLP) was used to determine the relationships among Capparis spp. Genetic distances, based on AFLP data were estimated for 45 accessions of Capparis species, from Spain, Morocco and Syria. The results of this analysis support the differentiation of four of the five taxa involved. The group of plants recognised as C. spinosa on the basis of morphological characters, includes several cultivars and appears in an intermediate position between C. orientalis and C. sicula and overlaps with C. orientalis. The other two species C. aegyptia and C. ovata are separate from the rest. Capparis spinosa had a low number of unique bands in comparison with the other species. Although these results cannot confirm the hybrid origin of C. spinosa, the distribution of the bands supports this hypothesis, the most likely parental species being C. orientalis and C. sicula. 相似文献