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21.
ANNE HUKKANEN HARRI KOKKO ANTONY BUCHALA JUKKA HÄYRINEN SIRPA KÄRENLAMPI 《Molecular Plant Pathology》2008,9(6):799-808
Benzothiadiazole (BTH) induces resistance to the downy mildew pathogen, Peronospora sparsa, in arctic bramble, but the basis for the BTH‐induced resistance is unknown. Arctic bramble cv. Mespi was treated with BTH to study the changes in leaf proteome and to identify proteins with a putative role in disease resistance. First, BTH induced strong expression of one PR‐1 protein isoform, which was also induced by salicylic acid (SA). The PR‐1 was responsive to BTH and exogenous SA despite a high endogenous SA content (20–25 µg/g fresh weight), which increased to an even higher level after treatment with BTH. Secondly, a total of 792 protein spots were detected in two‐dimensional gel electrophoresis, eight proteins being detected solely in the BTH‐treated plants. BTH caused up‐ or down‐regulation of 72 and 31 proteins, respectively, of which 18 were tentatively identified by mass spectrometry. The up‐regulation of flavanone‐3‐hydroxylase, alanine aminotransferase, 1‐aminocyclopropane‐1‐carboxylate oxidase, PR‐1 and PR‐10 proteins may partly explain the BTH‐induced resistance against P. sparsa. Other proteins with changes in intensity appear to be involved in, for example, energy metabolism and protein processing. The decline in ATP synthase, triosephosphate isomerase, fructose bisphosphate aldolase and glutamine synthetase suggests that BTH causes significant changes in primary metabolism, which provides one possible explanation for the decreased vegetative growth of foliage and rhizome observed in BTH‐treated plants. 相似文献
22.
D. CARL FREEMAN MICHELLE L. BROWN MELISSA DOBSON YOLANDA JORDAN ANNE KIZY CHRIS MICALLEF LEANDRIA C. HANCOCK JOHN H. GRAHAM JOHN M. EMLEN 《Biological journal of the Linnean Society. Linnean Society of London》2003,78(1):27-41
Fluctuating asymmetry measures random deviations from bilateral symmetry, and thus estimates developmental instability, the loss of ability by an organism to regulate its development. There have been few rigorous tests of this proposition. Regulation of bilateral symmetry must involve either feedback between the sides or independent regulation toward a symmetric set point. Either kind of regulation should decrease asymmetry over time, but only right–left feedback produces compensatory growth across sides, seen as antipersistent growth following perturbation. Here, we describe the developmental trajectories of perturbed and unperturbed leaves of pumpkin, Cucurbita pepo L., grown at three densities. Covering one side of a leaf with aluminium foil for 24 h perturbed leaf growth. Reduced growth on the perturbed side caused leaves to become more asymmetrical than unperturbed controls. After the treatment the size-corrected asymmetry decreased over time. In addition, rescaled range analysis showed that asymmetry was antipersistent rather than random, i.e. fluctuation in one direction was likely to be followed by fluctuations in the opposite direction. Development involves right–left feedback. This feedback reduced size-corrected asymmetry over time most strongly in the lowest density treatment suggesting that developmental instability results from a lack of resilience rather than resistance. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 78, 27–41. 相似文献
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ANNE M. MECKSTROTH A. KEITH MILES SUDEEP CHANDRA 《The Journal of wildlife management》2007,71(7):2387-2392
ABSTRACT In a study of predation on ground-nesting birds at South San Francisco Bay (South Bay), California, USA, we analyzed stomach contents and stable isotopes of carbon and nitrogen to identify commonly consumed prey. We obtained the stomach contents from 206 nonnative red foxes (Vulpes vulpes regalis) collected in the South Bay area and Monterey County during 1995–2001 and from 68 feral cats (Felis silvestris) from the South Bay area during 2001–2002. We determined prey identity, biomass, and frequency, described seasonal diet trends, and derived an Index of Relative Importance. Avian species were the most frequent prey we found in the stomachs of red foxes from South Bay (61%), whereas small rodents were most frequent for red foxes from Monterey County (62%). Small rodents were the most frequent prey we found in feral cats (63%). Carbon and nitrogen isotopic signatures for foxes supported stomach content findings. However, isotope results indicated that cats received a majority of their energy from a source other than rodents and outside the natural system, which differed from the stomach content analysis. We demonstrated the utility of both stable isotope and stomach content analyses to establish a more complete understanding of predators' diets. This information aids natural resource managers in planning and evaluating future predator-removal programs and increases our understanding of the impacts of nonnative foxes and cats on native species. 相似文献
25.
ANNE M. TRAINOR TANYA M. SHENK KENNETH R. WILSON 《The Journal of wildlife management》2007,71(2):469-477
ABSTRACT Riparian wetlands are complex ecosystems containing species diversity that may easily be affected by anthropogenic disturbances. Preble's meadow jumping mouse (Zapus hudsonius preblei) is a federally threatened subspecies dependent upon riparian wetlands along the Front Range of Colorado and southeastern Wyoming, USA. Although habitat improvements for Preble's meadow jumping mouse are designed at multiple spatial scales, most knowledge about its habitat requirements has been described at a landscape scale. Our objective was to improve our understanding of Preble's meadow jumping mouse microhabitat characteristics within high-use areas (hotspots), which are essential for the development of effective management and conservation strategies. We evaluated Preble's meadow jumping mouse habitat by describing areas of high use and no use as determined from monitoring radiocollared individuals. A comparison of microhabitat characteristics from random samples of high-use and no-use areas indicated that mice use areas closer to the center of the creek bed and positively associated with shrub, grass, and woody debris cover. Distance to center of the creek bed, and percent of shrub and grass cover also had the greatest relative importance of habitat variables modeled when describing high-use areas. High-use areas contained 3 times more grass cover than forb cover, and overall had a greater proportion of wetland shrub and grass cover. However, proportion of cover type (shrub or grass) did not vary greatly between high-use and no-use areas. Our results suggest that management and conservation efforts should continue to focus on establishment of native wetland vegetation near streams and creeks. For example, vegetation should include shrubs such as willow (Salix spp.), narrowleaf cottonwood (Populus angustifolia), alder (Alnus incana), grasses such as fescue (Fescue spp.), sedges (Carex spp.), and rush (Juncus spp). 相似文献
26.
PETER A. VESK ANNE E. ASHFORD ANNE-LAURE MARKOVINA & WILLIAM G. ALLAWAY 《The New phytologist》2000,145(2):333-346
The apoplasmic permeability of ectomycorrhizal roots of intact Eucalyptus pilularis seedlings infected with Pisolithus tinctorius on aseptic agar plates was examined using the nonbinding fluorochrome 8-hydroxypyrene-1,3,6-trisulphonate and lanthanum ions in conjunction with anhydrous freeze substitution and dry sectioning. Most mycorrhizas formed in the air above the agar surface, and in these the sheath rapidly became nonwettable and impermeable to the fluorochrome but was nevertheless permeable to lanthanum ions. In a few mycorrhizas which developed in contact with the agar the sheath remained permeable to both tracers when fully developed. This increased hydrophobicity of the sheath in mycorrhizas in the air above the agar surface might be explained by deposition of hydrophobins, but nevertheless it still allows an apoplasmic pathway for radial movement of ions. Regardless of their sheath permeation both apoplasmic tracers were always found throughout the Hartig net and were arrested at the Casparian bands and suberin lamellae of the exodermis. It is concluded that the fluorochrome must have moved longitudinally along the Hartig net which is a region of higher permeability than the sheath. Casparian bands in the exodermis of ectomycorrhizal roots have similar properties to those in nonmycorrhizal roots in excluding solutes and their exclusion of lanthanum ions indicates that they are not permeable to ions. The data do not support the concept of a totally sealed apoplasmic exchange compartment, but the differential permeability suggests that the sheath might allow radial transfer of ions but block loss of sugars and organic molecules of similar size. 相似文献
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ANNE MUST ENNO MERIVEE MARIKA MÄNd ANNE LUIK MIKK HEIDEMAA 《Physiological Entomology》2006,31(3):278-285
Abstract. Cold cells innervating antennal campaniform sensilla of the ground beetles Pterostichus oblongopunctatus (Fabricius, 1787) and Poecilus cupreus (Linnaeus, 1758) belonging to the tribe Pterostichini fire at a stationary rate of 22–23 imp s−1 at 23 °C. In P. oblongopunctatus , there is a strong negative correlation between the stationary firing rate of the cold cell and temperature. By contrast, no relationship between the firing rate and temperature is observed in P. cupreus. Mean peak frequencies, reaching up to nearly 500 Hz, and first-second firing rates, reaching up to 140 imp s−1 , are observed at the beginning of the phasic-tonic response to rapid cooling of the cold cells of P. cupreus, which are significantly higher than those for P. oblongopunctatus . However, firing rates of the cold cells of the two ground beetles studied do not differ 3 s later, during the tonic stabilization period of the response. The length of the long interspike period, lasting up to several seconds, at the beginning of rapid warming, is a positive function of the extent of change in temperature, and is longer in P. oblongopunctatus than in P. cupreus . These differences in the responses of the cold cells are related to the ecological preferences of the two ground beetles. 相似文献
29.
Multiple determinants influence root colonization and induction of induced systemic resistance by Pseudomonas chlororaphis O6 总被引:1,自引:0,他引:1
SONG HEE HAN ANNE J. ANDERSON KWANG YEOL YANG BAIK HO CHO KIL YONG KIM MYUNG CHUL LEE YONG HWAN KIM YOUNG CHEOL KIM 《Molecular Plant Pathology》2006,7(6):463-472
Colonization of the roots of tobacco by Pseudomonas chlororaphis O6 induces systemic resistance to the soft-rot pathogen, Erwinia carotovora ssp. carotovara SCC1. A screen of the transposon mutants of P. chlororaphis O6 showed mutants with about a fivefold reduction in ability to induce systemic resistance to the soft-rot disease. These mutations disrupted genes involved in diverse functions: a methyl-accepting chemotaxis protein, biosynthesis of purines, phospholipase C, transport of branched-chain amino acids and an ABC transporter. Additional mutations were detected in the intergenic spacer regions between genes encoding a GGDEF protein and fumarate dehydratase, and in genes of unknown function. The mutants in the ABC transporters did not display reduced root colonization. However, the other mutants had up to 100-fold reduced colonization levels. Generally the production of metabolites important for interactions in the rhizosphere, phenazines and siderophores, was not altered by the mutations. A reduced induction of systemic resistance by a purine biosynthesis mutant with a disrupted purM gene correlated with poor growth rate, lesser production of phenazines and siderophore and low levels of root colonization. These studies showed that multiple determinants are involved in the induction of systemic resistance, with there being a requirement for strong root colonization. 相似文献
30.
STEPHAN HÜLSMANN ANNEKATRIN WAGNER MATTHIAS PITSCH WOLFGANG HORN RÜDIGER PAUL ANNE ROTHER BETTINA ZEIS 《Freshwater Biology》2012,57(7):1458-1470
1. Winter conditions shape plankton dynamics and community composition in temperate regions, but their effect on dynamics and genetic composition of cyclical parthenogens like Daphnia is largely unclear. 2. For 5 years, we studied the dynamics, hatching from resting eggs and genetic structure of a D. galeata × longispina hybrid complex in a dimictic, temperate reservoir. Our main hypothesis was that higher spring densities and an earlier population peak will be observed after warmer winters, with a lower genetic diversity because of a lower contribution of resting eggs to population growth. 3. The study period could clearly be categorised into cold‐winter years (n = 3) and warm‐winter years (n = 2). Daphnia densities at the end of spring overturn were ~10‐fold lower after cold winters than after warm ones, but no pattern emerged concerning the timing and the height of the population peak in early summer. 4. Hatching intensity from resting eggs was higher and contributed up to 8.5% to Daphnia abundance in a cold‐winter year compared to a negligible contribution in a warm‐winter year. Consistent with this finding, new multilocus genotypes (MLGs) adding to the overwintering stock after the end of spring overturn and presumably originating from resting eggs increased genetic diversity and attained high frequencies within the population only after a cold winter. New MLGs were recorded also after warm winters, but they never gained dominance and no shift in genetic diversity was observed. However, genetic diversity was not generally reduced after warm winters. 5. Our results confirm earlier findings that winter conditions have only a limited effect on the main growth phase and the peak of Daphnia during late spring and early summer. However, winter conditions determine the contribution of resting eggs to the population development, which may profoundly alter the genetic composition of the population compared to the previous season. 相似文献