Reactions of root plasma membrane redox activities in iron-deficient cucumber plants after application of ionic and chelated copper

The effects of ionic (CuSO4) and chelated forms of copper (Cu(II)HEDTA, where HEDTA is N-(2-hydroxyethyl) ethylenediamine triacetic acid, applied at micromolar concentrations in nutrient solutions of cucumber plants grown hydroponically under conditions of iron deficiency (–Fe), were studied. Changes of plasma membrane reductase activity (PMRA) of intact roots after treatment with ionic or chelated copper were followed in (+Fe) and (–Fe) cucumber plants. Iron deprivation in nutrient solution provoked a great increase of ferric-chelate reductase activity (with substrate of Fe(III)HEDTA) and accelerated the cupric-chelate reductase activity (measured with Cu(II)Citrate as an electron acceptor) as well as the hexacyanoferrate(III) [HCF(III)] reductase activity. Continuous application of cupric ions in solutions of iron-deficient plants resulted in a dramatic inhibition of Fe(III)HEDTA and Cu(II)Citrate reductase activity. The reductase activity in iron-deficient cucumber roots, measured with HCF(III), was inhibited to a lower extent after cupric ions treatment. On the other hand, the cupric-chelate Cu(II)HEDTA, applied at the same concentrations in solutions with (–Fe) plants, maintained the high stimulation of plasma membrane ferric-chelate and cupric-chelate reductase activity and produced additional acceleration of HCF(III) reduction by cucumber roots. The treatment with Cu(II)HEDTA improved the growth and root PMRA as well as other iron-deficiency stress responses of cucumber plants

The 3-Base Periodicity and Codon Usage of Coding Sequences Are Correlated with Gene Expression at the Level of Transcription Elongation

Background: Gene transcription is regulated by DNA transcriptional regulatory elements, promoters and enhancers that are located outside the coding regions. Here, we examine the characteristic 3-base periodicity of the coding sequences and analyse its correlation with the genome-wide transcriptional profile of yeast. Principal Findings: The analysis of coding sequences by a new class of indices proposed here identified two different sources of 3-base periodicity: the codon frequency and the codon sequence. In exponentially growing yeast cells, the codon-frequency component of periodicity accounts for 71.9 % of the variability of the cellular mRNA by a strong association with the density of elongating mRNA polymerase II complexes. The mRNA abundance explains most of the correlation between the codon-frequency component of periodicity and protein levels. Furthermore, pyrimidine-ending codons of the four-fold degenerate small amino acids alanine, glycine and valine are associated with genes with double the transcription rate of those associated with purine-ending codons. Conclusions: We demonstrate that the 3-base periodicity of coding sequences is higher than expected by the codon usage frequency (CUF) and that its components, associated with codon bias and amino acid composition, are correlated with gene expression, principally at the level of transcription elongation. This indicates a role of codon sequences in maximising the transcription efficiency in exponentially growing yeast cells. Moreover, the results contrast with the common Darwinia

New records and noteworthy data of plants, algae and fungi in SE Europe and adjacent regions, 12

This paper presents new records and noteworthy data on the following taxa in SE Europe and adjacent regions: red algae Hildenbrandia rivularis, saprotrophic fungus Cryptomarasmius corbariensis, lichenised fungi Lecanora stenotropa, Micarea misella and Sticta sylvatica, liverworts Fossombronia caespitiformis and Peltolepis quadrata, mosses Dicranoweisia cirrata and Fissidens exilis, horsetail Equisetum × moorei, gymnosperm Juniperus virginiana, monocots Galanthus reginae-olgae subsp. vernalis and Spiranthes spiralis and dicots Linaria pelisseriana, Parthenocissus quinquefolia, Pilosella rhodopea and Taraxacum erythrospermum are given within SE Europe and adjacent regions

RESULTS OF TV IMAGING OF PHOBOS (EXPERIMENT VSK-FREGAT)

From February to March 1989 the Phobos 2 spacecraft took 37 TV images of Phobos at a distance of 190–1100 km. These images complement Mariner-9 and Viking data by providing higherresolution coverage of a large region West of the crater Stickney (40–160°W) and by providing disk-resolved measurements of surface brightness at a greater range of wavelengths and additional phase angles. These images have supported updated mapping and characterization of large craters and grooves, and have provided additional observations of craters\u27 and grooves\u27 bright rims. Variations in surface visible/nearinfrared color ratio of almost a factor of 2 have been recognized ; these variations appear to be associated with the ejecta of specific large impact craters. Updated determinations of satellite mass and volume allow calculation of a more accurate value of bulk density, 1.90 ± 0.1 g cm−3. This is significantly lower than the density of meteoritic analogs to Phobos\u27 surface, suggesting a porous interior perhaps containing interstitial ice

Sputtered ITO for application in thin-film silicon solar cells: Relationship between structural and electrical properties

Indium tin oxide (ITO) thin films for application in thin-film silicon solar cells with superior electrical and optical properties (resistivity ranging from 1.4 to 8.4x10-4 Ωcm; transparency of >80%) have been investigated. ITO layers were deposited by radio-frequency (RF) magnetron sputtering process at different argon gas pressures and substrate temperatures ranging from room temperature to 280°C. The main goal was to identify the relationship between structural and electrical properties. Generally, ITO layers were rather smooth with granular topography; electro-optically superior layers exhibited substantially different surface morphology of large, well-organized domain formations. Hall mobility of remarkably high value of 49 cm2/Vs (resistivity of 2.6x10-4 Ω.cm) was achieved for the ITO layers, which were deposited at surprisingly low temperature of 125°C. ITO deposition process has been successfully applied, even at room temperature, to fabricate front contacts for microcrystalline silicon solar cells, exhibiting excellent performance on both rigid and flexible substrates