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51.
A characteristic of the defence response is the immobilisation of wall proteins possibly through the formation of covalent cross-links and the subsequent barrier formation against pathogens. A requirement for this is the generation of active oxygen species, particularly hydrogen peroxide. In the present work, we examine in depth the requirement for H2O2 and the specificity of the immobilisation with respect to particular wall proteins. Salt-extractable wall proteins were analysed for hydroxyproline content and the subset of proteins with this post-translational modification was found to be small. About 50 proteins were found to be easily salt-extractable and in response to elicitor treatment about 5 were found to be specifically immobilised. Immobilisation was very rapid and completed within 15 min after elicitation, and dependent upon the type of elicitor and the intensity of the production of active oxygen species. N-terminal sequencing and amino acid analysis revealed that, apart from one polypeptide, all immobilised proteins were (hydroxy)proline-containing glycoproteins with O-linked oligosaccharide side chains. In contrast, N-linked glycoproteins were not immobilised. N-terminal protein sequencing revealed the immobilised HRGPs to be novel, but both extensin and PRP-like. Implications of these findings for both pathogenic and symbiotic processes are also discussed.  相似文献   
52.
Species attributes are commonly used to infer impacts of environmental change on multiyear species trends, e.g. decadal changes in population size. However, by themselves attributes are of limited value in global change attribution since they do not measure the changing environment. A broader foundation for attributing species responses to global change may be achieved by complementing an attributes‐based approach by one estimating the relationship between repeated measures of organismal and environmental changes over short time scales. To assess the benefit of this multiscale perspective, we investigate the recent impact of multiple environmental changes on European farmland birds, here focusing on climate change and land use change. We analyze more than 800 time series from 18 countries spanning the past two decades. Analysis of long‐term population growth rates documents simultaneous responses that can be attributed to both climate change and land‐use change, including long‐term increases in populations of hot‐dwelling species and declines in long‐distance migrants and farmland specialists. In contrast, analysis of annual growth rates yield novel insights into the potential mechanisms driving long‐term climate induced change. In particular, we find that birds are affected by winter, spring, and summer conditions depending on the distinct breeding phenology that corresponds to their migratory strategy. Birds in general benefit from higher temperatures or higher primary productivity early on or in the peak of the breeding season with the largest effect sizes observed in cooler parts of species' climatic ranges. Our results document the potential of combining time scales and integrating both species attributes and environmental variables for global change attribution. We suggest such an approach will be of general use when high‐resolution time series are available in large‐scale biodiversity surveys.  相似文献   
53.
Following the end‐Permian biotic crisis which led to the near extinction of crinoids, this echinoderm class rebounded rapidly during the Mesozoic, resulting in forms with important morphological and behavioural novelties. However, quantitative patterns of crinoid diversity during the Mesozoic remain largely unexplored. Here, we report results of analyses of the evolutionary dynamics of post‐Palaeozoic crinoid genera spanning a time interval between 250 and 70 Myr. We show that crinoids reached their Mesozoic peak of genus‐level richness during the Late Jurassic. We also document a major reorganization of different ecological crinoid groups in the Mesozoic. More specifically, the diversity of sessile forms generally increased towards the mid‐Mesozoic but decreased significantly starting in the Cretaceous, whereas the number of motile crinoid genera increased linearly during the Mesozoic. The possible role of biotic and abiotic factors in crinoid evolution is discussed.  相似文献   
54.
Drill holes made by predators in prey shells are widely considered to be the most unambiguous bodies of evidence of predator-prey interactions in the fossil record. However, recognition of traces of predatory origin from those formed by abiotic factors still waits for a rigorous evaluation as a prerequisite to ascertain predation intensity through geologic time and to test macroevolutionary patterns. New experimental data from tumbling various extant shells demonstrate that abrasion may leave holes strongly resembling the traces produced by drilling predators. They typically represent singular, circular to oval penetrations perpendicular to the shell surface. These data provide an alternative explanation to the drilling predation hypothesis for the origin of holes recorded in fossil shells. Although various non-morphological criteria (evaluation of holes for non-random distribution) and morphometric studies (quantification of the drill hole shape) have been employed to separate biological from abiotic traces, these are probably insufficient to exclude abrasion artifacts, consequently leading to overestimate predation intensity. As a result, from now on, we must adopt more rigorous criteria to appropriately distinguish abrasion artifacts from drill holes, such as microstructural identification of micro-rasping traces.  相似文献   
55.
We have performed the molecular dynamics simulations for the free cholesterol cluster and the same cluster located near the carbon nanotube. We have found that the cholesterol molecules quite evenly cover the surface of single walled armchair (10, 10) carbon nanotube, forming the molecular layer. Moreover, the characteristic alignment of cholesterol molecules within the layer (along the nanotube) is observed. The comparison of the structural and dynamical observable characterizing cholesterol molecule is presented and discussed, both for the cluster with and without the presence of the nanotube.  相似文献   
56.
We have made the molecular dynamics (MD) simulations for the cluster of cholesterols localized near the protein farnesyltransferase (1FT2) at the physiological temperature T=309.75K. We have observed that the cholesterol molecules form a lodgment on the surface of protein. Several physical characteristics of the deposited cholesterol cluster have been calculated among those: the mean square displacement, diffusion coefficient, linear and angular velocity autocorrelation function and their Fourier transforms.  相似文献   
57.
The aim of this study was to investigate the ionizing radiation effects, in the form of an electron beam, on itraconazole (ITR) in the solid phase. It was found that the ITR, under the influence of a standard 25 kGy dose of radiation used for the sterilization of drug substances, decomposed at 0.4%. Moreover, a gentle change of colour and a decrease in melting point does not exceed pharmacopoeial standards causing that ITR can be sterilized by radiation method. The use of high 400 kGy radiation doses resulted in a 6.5% decomposition of the ITR and eight radiodegradation products were found. However, with the exception of differential scanning calorimetry (DSC), the X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR) and ultraviolet-visible (UV-vis) methods showed no changes in the form and the morphology of the crystals. The structures of all those compounds were investigated. It was confirmed that the ITR decomposition takes place by dehalogenation (one of Cl atom elimination), the oxidation in isobutyl residue (beside the triazole ring) and C-O bond rupture.KEY WORDS: antifungal azole, DSC, itraconazole, product radiolysis, radiation sterilization  相似文献   
58.
THE AIM OF THE STUDY: To investigate by means of pattern visual evoked potentials (PVEPs) early neuropathic changes in Graves' ophthalmopathy (GO) patients without any clinical symptoms of optic neuropathy in order to evaluate the prevalence of subclinical optic neuropathy in GO patients and to elucidate whether there is a relationship between PVEP (P100 and N75 latency), intraocular pressure (IOP) and exophthalmometry. MATERIAL AND METHODS: Two groups of patients were examined: 15 patients with GO without clinical signs of dysthyroid optic neuropathy (DON) and 12 healthy controls. The correlations between the N75 and P100 latencies, IOP and Hertel exophthalmometry were investigated. RESULTS: The mean PVEP N75 and P100 latencies were significantly delayed in the GO uncomplicated with DON in comparison with controls (LP100- 106.2 +/- 4.4 ms vs. 102.4 +/- 2.7 ms, p < 0.01 and LN75- 79.0 +/- 3.7 ms vs. 73.9 +/- 2.8 ms, p < 0.001). In GO patients we documented a positive correlation between the LN75 latency and exophthalmometric readings (R = 0.51; p < 0.01). The value of LP100 and LN75 was above the normal limit in 5/30 eyes (17%) and in 3/30 eyes (10%) respectively. CONCLUSIONS: The assessment of PVEPs (especially the P100 latency) in GO patients without clinical signs of DON is a useful tool for the early diagnosis of optic nerve involvement.  相似文献   
59.
The aim of the study was to assess chosen factors of genetic susceptibility to DMT1: DRB1, DQB1, and TNF-alpha polymorphisms-308 (G/A) in children with DMT1 and their up-to-now healthy siblings. Then we tested whether the association between TNF-alpha genes and DMT1 is independent of HLA. 87 diabetic children, their 78 siblings, and 85 persons from healthy control group were followed up. The highest risk of DMT1 was connected with alleles: DRB1*0401 (OR = 3.39; CI: 1.55-7.41), DRB1*0301 (OR = 2.72; CI: 1.48-5.01), DQB1*0201 (OR = 4.04; CI: 2.17-7.52), DQB1*0302 (OR = 5.08; CI: 2.54-10.14), and TNF-alpha-308 A allele (OR = 2.59; CI: 1.23-5.44). Moreover linkage disequilibrium for TNF-alpha-308 A allele with DRB1*0301 and DQB1*0201 was observed in both diabetic children and their siblings. Diabetic children and their siblings present similar genetic risk factors for DMT1. The association between TNF-alpha-308 A allele and DMT1 is dependent of HLA-DRB1 and DQB1 alleles.  相似文献   
60.
In the first step of this investigation the toxicity of Ni2+, Cu2+, and Zn2+ ions to the emulsifier producing strain of Curvularia lunata was assessed. Among all the heavy metals studied, Ni2+ ions were found to be the most toxic to C. lunata, whereas Zn2+ ions exhibited the lowest toxicity. Moreover, only Ni2+, when used at sublethal concentration (5 mM) caused lysis of some hyphal tip cells after a short-term exposure (5 h). In the next step, emulsifier production, accumulation of heavy metals by mycelia and emulsifier as well as saturation of cellular fatty acids were examined in 48-h-old cultures where fungal growth intensity was not inhibited by heavy metals (in the presence of Ni2+, Cu2+, and Zn2+ ions at the initial concentration of 1, 5, and 15 mM, respectively) and in cultures where approximately 50% biomass inhibition occurred (in the presence of Ni2+, Cu2+, and Zn2+ ions at the initial concentrations of 3, 10, and 17.5 mM, respectively). Among all the heavy metals studied only Ni2+ ions did not induce emulsifier production. As compared with the control, only biomass treated with Ni2+ ions displayed an increase in total lipid saturation. This effect resulted mainly from the decrease in linoleic acid (18:2) content correlated with the increase in the amount of stearic acid (18:0). The possible mechanisms by which Ni2+ ions could alter the fatty acid profile of C. lunata and the protective role of the emulsifier were also discussed.  相似文献   
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