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141.
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Sporisorium warambiense is described and illustrated from the ovaries of Xerochloa laniflora from the Pilbara region of Western Australia. The smut fungus is characterized by sori restricted to the ovaries, presence
of three simple, stout, narrowing columellae, dark reddish-brown spore balls, dimorphic spores (darker outer spores and lighter
inner spores), and the absence of sterile cells. The differences between Sporisorium warambiense and three other smuts that infect Xerochloa (Sporisorium xerofasciculatum, Tilletia xerochloae, and Ustilago xerochloae), as well as comparable Sporisorium species on other grass genera from the tribe Paniceae are discussed. All Xerochloa smuts are endemic to Australia. 相似文献
144.
Sarewicz M Pietras R Froncisz W Osyczka A 《Metallomics : integrated biometal science》2011,3(4):404-409
The reaction of water-soluble cytochrome c (c(2)) with its physiological redox partners is facilitated by electrostatic attractions between the two protein surfaces. Using spin-labeled cytochrome c(2) from Rhodobacter capsulatus and pulse electron paramagnetic resonance (EPR) measurements we compared spatial orientation of cytochrome c(2) upon its binding to surfaces of opposite charge. We observed that cytochrome c(2) can use its negatively charged "back" side when exposed to interact with positively charged surfaces (DEAE resin) which is the opposite to the use of its positively charged "front" side in physiological interaction with negatively charged binding domain of cytochrome bc(1). The later orientation is also adopted upon non-physiological binding of cytochrome c(2) to negatively charged carboxymethyl cellulose resin. These results directly demonstrate how the electric dipolar nature of cytochrome c(2) influences its orientation in interactions with charged surfaces, which may facilitate collisions with other redox proteins in a proper orientation to support physiologically-competent electron transfer. Saturation recovery EPR provides an attractive tool for monitoring spatial orientation of proteins in their interaction with surfaces in liquid phase. It is particularly valuable for metalloproteins engaged in redox reactions as a means to monitor the geometry and dynamics of formation of protein complexes in measurements that are independent of electron transfer processes. 相似文献
145.
Kayser M Lao O Anslinger K Augustin C Bargel G Edelmann J Elias S Heinrich M Henke J Henke L Hohoff C Illing A Jonkisz A Kuzniar P Lebioda A Lessig R Lewicki S Maciejewska A Monies DM Pawłowski R Poetsch M Schmid D Schmidt U Schneider PM Stradmann-Bellinghausen B Szibor R Wegener R Wozniak M Zoledziewska M Roewer L Dobosz T Ploski R 《Human genetics》2005,117(5):428-443
To test for human population substructure and to investigate human population history we have analysed Y-chromosome diversity using seven microsatellites (Y-STRs) and ten binary markers (Y-SNPs) in samples from eight regionally distributed populations from Poland (n=913) and 11 from Germany (n=1,215). Based on data from both Y-chromosome marker systems, which we found to be highly correlated (r=0.96), and using spatial analysis of the molecular variance (SAMOVA), we revealed statistically significant support for two groups of populations: (1) all Polish populations and (2) all German populations. By means of analysis of the molecular variance (AMOVA) we observed a large and statistically significant proportion of 14% (for Y-SNPs) and 15% (for Y-STRs) of the respective total genetic variation being explained between both countries. The same population differentiation was detected using Monmoniers algorithm, with a resulting genetic border between Poland and Germany that closely resembles the course of the political border between both countries. The observed genetic differentiation was mainly, but not exclusively, due to the frequency distribution of two Y-SNP haplogroups and their associated Y-STR haplotypes: R1a1*, most frequent in Poland, and R1*(xR1a1), most frequent in Germany. We suggest here that the pronounced population differentiation between the two geographically neighbouring countries, Poland and Germany, is the consequence of very recent events in human population history, namely the forced human resettlement of many millions of Germans and Poles during and, especially, shortly after World War II. In addition, our findings have consequences for the forensic application of Y-chromosome markers, strongly supporting the implementation of population substructure into forensic Y chromosome databases, and also for genetic association studies. 相似文献
146.
147.
Marcin?Wróbel Magdalena?Karama Ryszard?Amarowicz Ewa?Fr czek Stanis?aw?WeidnerEmail author 《Acta Physiologiae Plantarum》2005,27(3):313-320
We studied the alterations in phenolic compounds in grape seeds during their stratification and germination under optimal
conditions (+25 °C) and at low temperature (+10 °C). Biological materials in the study were seeds of Vitis riparia. Phenolic compounds were extracted from defatted seeds using 80 % methanol or 80 % acetone. The content of total phenolics
was determined with the Folin-Ciocalteau reagent, while the content of tannins was determined by vanillin assay and the protein
(BSA) precipitation method. The RP-HPLC method was used to determine phenolic compounds (phenolic acids, catechins) in the
extracts. High amounts of tannins, catechins, gallic acid and lesser amounts of p-coumaric acid were found in the seeds. The content of total phenolics in acetone extracts was higher than that obtained using
methanol. The amounts of phenolic acids and tannins found in V. riparia seeds after stratification were much lower. It may confirm a possible role of these compounds in dormancy of V. riparia seeds. After 72 h of low temperature treatment, inhibition of grape root growth and biochemical changes in seeds were detected.
The chilling stimulated increased accumulation of some phenolic compounds (free gallic acid and catechins) in the seeds. These
substances can protect plants against some abiotic stressors. 相似文献
148.
149.
Stepinski J Zuberek J Jemielity J Kalek M Stolarski R Darzynkiewicz E 《Nucleosides, nucleotides & nucleic acids》2005,24(5-7):629-633
Chemical synthesis of a series of novel dinucleoside cap analogues, m7GpppN, where N is formycin A, 3'-O-methylguanosine, 9-beta-D-arabinofuranosyladenine, and isoguanosine, has been performed using our new methodology. The key reactions of pyrophosphate bonds formation were achieved in anhydrous dimethylformamide solutions employing the catalytic properties of zinc salts. Structures of the new cap analogues were confirmed by 1H NMR and 31p NMR spectra. The binding affinity of the new cap analogues for murine eIF4E(28-217) were determined spectroscopically showing the highest association constant for the analogue that contains formycin A. 相似文献
150.
Cyclic AMP receptor protein (CRP) regulates the expression of more then 100 genes in Escherichia coli. It is known that the allosteric activation of CRP by cAMP involves a long-distance signal transmission from the N-terminal cAMP-binding domain to the C-terminal domain of CRP responsible for the interactions with specific sequences of DNA. In this report we have used a CRP mutant containing a single Trp13 located in the N-terminal domain of the protein. We applied the iodide and acrylamide fluorescence quenching method in order to study how different DNA sequences and cAMP binding induce the conformational changes in the CRP molecule. The results presented provide evidence for the occurrence of a long-distance conformational signal transduction within the protein from the C-terminal DNA-binding domain to the N-terminal domain of CRP. This conformational signal transmission depends on the promoter sequence. We also used the stopped-flow and Forster resonance energy transfer between labeled Cys178 of CRP and fluorescently labeled DNA sequences to study the kinetics of DNA-CRP interactions. The results thus obtained lead to the conclusion that CRP can exist in several conformational states and that their distribution is affected by binding of both the cAMP and of specific DNA sequences. 相似文献