RESUMEN
Perennial ryegrass (Lolium perenne L.) is one of the most popular grass species in Europe. It is commonly used for establishing the lawns in urban areas, where the salt stress is one of the major environmental conditions limiting its growth. The basic aim of this study was the detailed in vivo analysis of the changes in photosynthetic efficiency, induced by salt stress, of two lawn varieties of Perennial ryegrass and to find out the variety of better properties to create lawn on the soils contaminated with salt. Two lawn varieties of L. perenne L. were used: Nira and Roadrunner. The salinization was applied 8 weeks after sowing by adding NaCl in water solution (0, 0.15, and 0.30 M). The measurements were carried out 8 times: 0, 24, 48, 96, 144, 192, 240 and 288 h after salinization. Our results revealed that the disturbance of PSII function could easily be estimated by measuring chlorophyll a fluorescence and analyzing that signal by JIP-test. Our work allowed to identify various limiting parameters of photosynthetic efficiency of perennial ryegrass lawn varieties grown under salt stress conditions. This knowledge can allow for selection of plants with a higher potential photosynthetic efficiency (vitality) during salt stress conditions, that can be used successfully neighboring roads, where salt is applied.
Asunto(s)
Clorofila/metabolismo , Complejo de Proteína del Fotosistema II/metabolismo , Poaceae/metabolismo , Sales (Química) , Estrés Fisiológico , Clorofila A , Fluorescencia , Complejo de Proteína del Fotosistema II/química , Conformación ProteicaRESUMEN
A novel, nitroreductase (NTR) containing a sequence of six cysteine amino acids, enabling strong thiolate bonds to form on a gold electrode surface without the loss of enzyme activity, was genetically engineered. The enzyme was directly immobilised at a gold electrode without the need for pre-treatment of the surface with a self-assembled monolayer or a conducting polymer. The ensemble was used to develop an amperometric biosensor for the detection of explosives containing nitroaromatic compounds. Preliminary results demonstrate detection levels down to 100 parts per trillion, signifying tremendous promise towards an in situ sensor for the detection of explosives.
Asunto(s)
Técnicas Biosensibles/métodos , Enzimas Inmovilizadas/química , Sustancias Explosivas/análisis , Nitrorreductasas/química , Electroquímica , Escherichia coli/genética , Ingeniería Genética , Especificidad por SustratoRESUMEN
[reaction: see text]. Irradiation of 4,5-dithiophen-3-yl-[1,3]dithiol-2-one 1 at lambda > 330 nm gave the thieno[3,4-c]dithiine 2, the first example of this heterocyclic system
RESUMEN
Capsular exopolymers (EPS) of the bacterium Pseudomonas sp. NCIMB 2021 are allowed to self-assemble on hydrophilic and hydrophobic gold surfaces. Tapping mode atomic force microscopy confirms the differences in the surface topography between EPS adsorbed on both surfaces. Fourier-transform IR spectroscopy indicates that the EPS surface coverage is much greater on the hydrophobic surface. Furthermore, an increased contribution is observed from hydrophobic (i.e., methyl and tyrosyl residues) and electrostatic (i.e., carboxylate residues) groups at the hydrophobic surface, but there is relatively less neutral polymer compared to the hydrophilic surface. The behavior of this EPS is in agreement with the behavior of cells of Pseudomonas sp. NCIMB 2021 at hydrophilic and hydrophobic surfaces.