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971.
Artur Mikiciński Piotr Sobiczewski Monika Sulikowska Joanna Puławska Jadwiga Treder 《Journal of Phytopathology》2010,158(4):201-209
Soft rot is the most important disease on calla lily in Poland. The isolation of the presumptive pathogen from symptomatic tubers on nutrient agar yielded bacteria with different colony morphology. Of 41 isolates collected, 10 showed pectolytic activity on crystal violet pectate medium and caused soft rot on potato slices. All pectolytic bacteria appeared to be Gram‐negative rods producing typical soft rot on inoculated leaf petioles of calla lily. Bacteria with colonies which morphologically resembled those used for inoculation were re‐isolated from diseased petioles. Their identification was based on phenotypic characters and sequence of the gene fragment coding 16S rRNA. It was found that, in addition to Pectobacterium carotovorum subsp. carotovorum, soft rot of calla lily can be caused by Pectobacterium carotovorum subsp. atrosepticum, Pseudomonas marginalis, Pseudomonas veronii and Chryseobacterium indologenes. The latter two are described for the first time as plant pathogens. The pectolytic activity of all identified bacteria, except that of P. carotovorum subsp. atrosepticum, was lower than that of P. carotovorum subsp. carotovorum, but strains of P. veronii showed a higher activity than P. marginalisand C. indologenes species. 相似文献
972.
Piotr Stefanowicz Monika Kijewska Katarzyna Kapczyńska Zbigniew Szewczuk 《Amino acids》2010,38(3):881-889
Two procedures of glycated peptides’ synthesis have been developed. The first method involves reductive alkylation of the
ε-amino groups of lysine with 2,3:4,5-di-O-isopropylidene-β-d-arabino-hexos-2-ulo-2,6-pyranose in the presence of sodium cyanoborohydride on solid support. The second one uses a new fully
protected lysine derivative, which is a building block designed for direct introduction of the glycated lysine moiety into
a peptide, according to the standard solid phase synthesis protocol. The applicability of the proposed methods for the synthesis
of peptide-derived Amadori products is discussed. The structure of the synthesized glycated peptides was confirmed by high-resolution
mass spectrometry and enzymatic hydrolysis. Circular dichroism studies, performed in water solution, revealed that the formation
of the Amadori rearrangement product in the lysine side chain does not influence significantly the conformational preferences
of the peptides studied. However, when the solvent was changed to trifluoroethanol, the glycated peptides preferred β-turn
conformation. 相似文献
973.
Relationship between genotype and soil environment during colonization of poplar roots by mycorrhizal and endophytic fungi 总被引:1,自引:0,他引:1
Leszek Karliński Maria Rudawska Barbara Kieliszewska-Rokicka Tomasz Leski 《Mycorrhiza》2010,20(5):315-324
Poplars are among the few tree genera that can develop both ectomycorrhizal (ECM) and arbuscular (AM) associations; however,
variable ratios of ECM/AM in dual mycorrhizal colonizations were observed in the roots of a variety of poplar species and
hybrids. The objective of our study was to analyze the effect of internal and external factors on growth and dual AM and ECM
colonization of poplar roots in three 12–15-year-old common gardens in Poland. We also analyzed the abundance of nonmycorrhizal
fungal endophytes in the poplar roots. The Populus clones comprised black poplars (Populus deltoides and P. deltoides × Populus nigra), balsam poplars (Populus maximowiczii × Populus trichocarpa), and a hybrid of black and balsam poplars (P. deltoides × P. trichocarpa). Of the three sites that we studied, one was located in the vicinity of a copper smelter, where soil was contaminated with
copper and lead. Poplar root tip abundance, mycorrhizal colonization, and soil fungi biomass were lower at this heavily polluted
site. The total mycorrhizal colonization and the ratio of ECM and AM colonization differed among the study sites and according
to soil depth. The influence of Populus genotype was significantly pronounced only within the individual study sites. The contribution of nonmycorrhizal fungal endophytes
differed among the poplar clones and was higher at the polluted site than at the sites free of pollution. Our results indicate
that poplar fine root abundance and AM and ECM symbiosis are influenced by environmental conditions. Further studies of different
site conditions are required to characterize the utility of poplars for purposes such as the phytoremediation of polluted
sites. 相似文献
974.
Ecosystems worldwide are threatened with the extinction of plants and, at the same time, invasion by new species. Plant invasiveness and loss of species can be caused by similar but opposing pressures on the community structures. Arbuscular mycorrhizal fungi (AMF) can have multiple positive effects on plant growth, productivity, health, and stress relief. Many endangered species live in symbiosis with AMF. However, the list of the International Union for Conservation of Nature and Natural Resources (IUCN Red List of Threatened Species) indicates that the mycorrhizal status of most of the threatened species has not been assessed. Rare plants often occur in specialized and also endangered habitats and might utilize specialized or unique AMF. The specificity of any endangered plant to its AMF population has not been investigated. Because most of the current AMF isolates that are available colonize a broad range of plant species, selected inocula could be used to promote growth of endangered plants before the proper and more effective indigenous AMF are characterized. Application of AMF in field sites to protect endangered plants is hardly feasible due to the complexity of plant community structures and the large amount of fungal inocula needed. Endangered plants could, however, be grown as greenhouse cultures together with appropriate fungi, and, at the relevant developmental stage, they could be re-planted into native sites to prevent extinction and to preserve plant community ecology. 相似文献
975.
Ditkowski B Troć P Ginda K Donczew M Chater KF Zakrzewska-Czerwińska J Jakimowicz D 《Molecular microbiology》2010,78(6):1403-1415
Bacterial chromosome segregation usually involves cytoskeletal ParA proteins, ATPases which can form dynamic filaments. In aerial hyphae of the mycelial bacterium Streptomyces coelicolor, ParA filaments extend over tens of microns and are responsible for segregation of dozens of chromosomes. We have identified a novel interaction partner of S. coelicolor ParA, ParJ. ParJ negatively regulates ParA polymerization in vitro and is important for efficient chromosome segregation in sporulating aerial hyphae. ParJ-EGFP formed foci along aerial hyphae even in the absence of ParA. ParJ, which is encoded by sco1662, turned out to be one of the five actinobacterial signature proteins, and another of the five is a ParJ paralogue. We hypothesize that polar growth, which is characteristic not only of streptomycetes, but even of simple Actinobacteria, may be interlinked with ParA polymer assembly and its specific regulation by ParJ. 相似文献
976.
Louis J Lorenc-Kukula K Singh V Reese J Jander G Shah J 《The Plant journal : for cell and molecular biology》2010,64(5):800-811
The green peach aphid (GPA) (Myzus persicae Sülzer) is an important sap-sucking pest of a large variety of plants, including Arabidopsis thaliana. Arabidopsis utilizes a combination of defenses that deter insects from settling on the plant, limit insect feeding and curtail insect reproduction. We demonstrate that the previously uncharacterized Arabidopsis MPL1 (MYZUS PERSICAE-INDUCED LIPASE1) gene has an important role in defense against the GPA. MPL1 expression was rapidly induced to high level in GPA-infested plants. Furthermore, the GPA population was larger on the mpl1 mutant than the wild-type (WT) plant. In contrast, constitutive over-expression of MPL1 from the Cauliflower mosaic virus 35S gene promoter curtailed the size of the GPA population. Insect settling and feeding behavior were unaffected on the mpl1 mutant. However, compared with the phloem-sap enriched petiole exudate from the WT plant, mpl1 petiole exudate was deficient in an activity that restricts insect reproduction on a synthetic diet. Furthermore, MPL1 was required for the heightened accumulation of an antibiotic activity in petiole exudate of the Arabidopsis ssi2 mutant, which exhibits enhanced resistance to GPA. These results indicate that MPL1 has an essential function in antibiosis against GPA. The MPL1 protein exhibits homology to lipases and recombinant MPL1 has lipase activity, thus suggesting that a MPL1-dependent lipid, or a product thereof, has an important role in antibiosis against GPA. 相似文献
977.
978.
In this study, we examined the response of glioma C6 cells to 2′,3′-O-(4-benzoylbenzoyl)-ATP (BzATP) and showed that the BzATP-induced calcium signaling does not involve the P2X7 receptor activity. We show here that in the absence of extracellular Ca2+, BzATP-generated increase in [Ca2+]i
via Ca2+ release from intracellular stores. In the presence of calcium ions, BzATP established a biphasic Ca2+ response, in a manner typical for P2Y receptors. Brilliant Blue G, a selective antagonist of the rat P2X7 receptor, did not reduce any of the two components of the Ca2+ response elicited by BzATP. Periodate-oxidized ATP blocked not only BzATP- but also UTP-induced Ca2+ elevation. Moreover, BzATP did not open large transmembrane pores. What is more, a cross-desensitization between UTP and
BzATP occurred, which clearly shows that in glioma C6 cells BzATP activates most likely the P2Y2 but not the P2X7 receptors. 相似文献
979.
Pawel Mazur Tomasz Magdziarz Andrzej Bak Zdzislaw Chilmonczyk Teresa Kasprzycka-Guttman Irena Misiewicz-Krzemińska Katarzyna Skupińska Jaroslaw Polanski 《Journal of molecular modeling》2010,16(7):1205-1212
Isothiocyanates (ITC) are well-known chemopreventive agents extracted from vegetables. This activity results from the activation
of human oxidoreductase. In this letter, the uncompetitive activatory mechanism of ITC was investigated using docking and
molecular dynamics simulations. This indicates that NAD(P)H:quinone oxidoreductase can efficiently improve enzyme-substrate
recognition within the catalytic site if the ITC activator supports the interaction in the uncompetitive binding site. 相似文献
980.
Muskrat (Ondatra zibethicus) decline after the expansion of American mink (Neovison vison) in Poland
Marcin Brzeziński Jerzy Romanowski Michał Żmihorski Karolina Karpowicz 《European Journal of Wildlife Research》2010,56(3):341-348
Field survey data in Central Poland revealed that the proportion of sites inhabited by muskrats decreased from 44% to 7% over one decade. This corresponded to the decline in hunting bags of muskrat over the whole of Poland. The largest hunting harvest of muskrat was recorded in 1987/1988 (66,416 individuals), the smallest in 2007/2008 (4,567 individuals). The decline in hunting bags occurred in all regions analysed; however, it was most rapid in the north and north-east. Before the expansion of mink, which started in northern Poland at the beginning of the 1980s, muskrat densities in particular regions depended on the availability of aquatic habitats. A comparison of hunting bags of muskrat and American mink in years 2002–2008 indicated a significant negative correlation between the numbers of these two species harvested in seven regions of Poland. The negative correlation between numbers of muskrat and mink suggests that mink predation is one of the most important factors in the decline of the muskrat population in Poland. 相似文献