Genetic control of purothionins in wheat: problems of the aneuploid analysis when searching for regulatory genes

The study of the genetic control of purothionins in wheat endosperm illustrates some of the problems and pitfalls faced in aneuploid analysis of regulatory effects. Biochemical and genetic evidence is presented indicating that the possible regulatory effect of genes located in group 5 chromosomes on the expression of the purothionin structural genes located in group 1 chromosomes is not actually operating "in vivo"

Expression of homoeologous molecular systems in wheat alloploids

Allopolyploidy is widespread in the plant kingdom, where it has been of considerable evolutionary significance. Although the existence of heterotic interactions between the genomes that make up an alloploid have been generally assumed, the precise nature of these interactions has not been extensively investigated. Presently available evidence about metabolic integration of the wheat genomes is examined in search of new insights about the different modes of genome interaction. Although additive expression seems to be the case for many homoeologous systems, more complex patterns of integration have become evident. Examples of enzyme subunit complementation, gene compensation and other dosage effects, holoprotein completion, and complementation of metabolic pathways are discussed

Low cost time division multiplexing of identical optical fibre ring intensity sensors

A time division multiplexing (TDM) array for passive multiplexing of identical fibre, optic intensity sensors has been demonstrated. Microbending loss sensors are introduced in fibre optic rings and pressure information is directly detected, demultiplexed and demodulated from the relative amplitude of the first two pulses produced on each ring. Several dynamic ranges from 6 dB to 14 dB are shown. A comparison between both fibre optic ring and Mach-Zehnder structure impulse responses is carried out and the consequences derived from second- and higher-order recirculating ring pulses are also evaluated. This technique can be applied to those TDM intensity sensing schemes which require low cost, high number of identical sensors, and suffer high element loss and undersirable intensity fluctuations at low frequencies

Selective disulphide linkage of plant thionins with other proteins

Thionins are shown to form disulphide linkages with other proteins. The reaction with bacterial enzymes β-glucuronidase and neomycin phosphotransferase II could be prevented and reversed with dithiothreitol and blocked with N-ethylmaleimide. Other cysteine-rich low-molecular-weight toxic peptides from plants (LTP-3 from barley and P19 from potato) did not react as the thionins. Certain systeine-containing proteins, such bovine serum albumin, ovalbumin and cytochrome c, reacted with thionins, while others, including carbonic anhydrase, soybean trypsin inhibitor, bovine-lung trypsin inhibitor and phosphorylase B did not. Selectivity of the reaction with a periplasmic component of the phytopathogenic bacterium Pseudomonas solanacearum was also shown

Ingeniería molecular en "Triticum"

Se resumen las investigaciones realizadas sobre genética bioquímica de la especie aloploide de Triticum aestivum L. (trigo común). Dichas investigaciones abarcan los siguientes aspectos: a) localización cromosómica de genes que controlan sistemas moleculares; b) formas de interacción entre los genomios integrados en dicha especie; c) transferencia genética extraespecífica y extragenérica desde Aegilops ventricosa, Sécale cereale y Agropyron elongatum a trigo. Se especula sobre las implicaciones evolutivas de los resultados obtenidos y se enumeran las aplicaciones prácticas

Synthetic and structural studies on Pyrularia pubera thionin: a single-residue mutation enhances activity against Gram-negative bacteria

The thionin from Pyrularia pubera (Pp-TH), a 47-residue peptide with four internal disulfide bonds, was efficiently produced by chemical synthesis. Its antimicrobial activity in vitro against several representative pathogens (EC50=0.3–3.0 μM) was identical to that of natural Pp-TH. This peptide has a unique Asp32 instead of the consensus Arg found in other thionins of the same family. In order to evaluate the effect of this mutation, the Arg32 analogue (Pp-TH(D32R)) was also synthesized and showed a significant increase in antibiotic activity against several Gram-negative bacteria, whereas it retained the same activity against other pathogens. The overall structure of Pp-TH(D32R) was maintained, though a slight decrease in the helical content of the peptide was observed

Structural dissection of a highly knotted peptide reveals minimal motif with antimicrobial activity

The increasing occurrence of bacterial resistance to antibiotics is driving a renewed interest on antimicrobial peptides, in the hope that understanding the structural features responsible for their activity will provide leads into new anti-infective drug candidates. Most chemical studies in this field have focused on linear peptides of various eukaryotic origins, rather than on structures with complex folding patterns found also in nature. We have undertaken the structural dissection of a highly knotted, cysteine-rich plant thionin, with the aim of defining a minimal, synthetically accessible, structure that preserves the bioactive properties of the parent peptide. Using efficient strategies for directed disulfide bond formation, we have prepared a substantially simplified (45% size reduction) version with undiminished antimicrobial activity against a representative panel of pathogens. Analysis by circular dichroism shows that the downsized peptide preserves the central double alpha-helix of the parent form as an essential bioactive motif. Membrane permeability and surface plasmon resonance studies confirm that the mechanism of action remains unchanged

Antibiotic activities of peptides, hydrogen peroxide and peroxynitrite in plant defence

Genes encoding plant antibiotic peptides show expression patterns that are consistent with a defence role. Transgenic over-expression of defence peptide genes is potentially useful to engineer resistance of plants to relevant pathogens. Pathogen mutants that are sensitive to plant peptides in vitro have been obtained and a decrease of their virulence in planta has been observed, which is consistent with their hypothetical defence role. A similar approach has been followed to elucidate the potential direct anti-microbial role of hydrogen peroxide. Additionally, a scavenger of peroxynitrite has been used to investigate its involvement in plant defenc

Evolution of the use of corticosteroids for the treatment of hospitalised COVID-19 patients in Spain between March and November 2020: SEMI-COVID national registry

Objectives: Since the results of the RECOVERY trial, WHO recommendations about the use of corticosteroids (CTs) in COVID-19 have changed. The aim of the study is to analyse the evolutive use of CTs in Spain during the pandemic to assess the potential influence of new recommendations. Material and methods: A retrospective, descriptive, and observational study was conducted on adults hospitalised due to COVID-19 in Spain who were included in the SEMI-COVID- 19 Registry from March to November 2020. Results: CTs were used in 6053 (36.21%) of the included patients. The patients were older (mean (SD)) (69.6 (14.6) vs. 66.0 (16.8) years; p < 0.001), with hypertension (57.0% vs. 47.7%; p < 0.001), obesity (26.4% vs. 19.3%; p < 0.0001), and multimorbidity prevalence (20.6% vs. 16.1%; p < 0.001). These patients had higher values (mean (95% CI)) of C-reactive protein (CRP) (86 (32.7-160) vs. 49.3 (16-109) mg/dL; p < 0.001), ferritin (791 (393-1534) vs. 470 (236- 996) µg/dL; p < 0.001), D dimer (750 (430-1400) vs. 617 (345-1180) µg/dL; p < 0.001), and lower Sp02/Fi02 (266 (91.1) vs. 301 (101); p < 0.001). Since June 2020, there was an increment in the use of CTs (March vs. September; p < 0.001). Overall, 20% did not receive steroids, and 40% received less than 200 mg accumulated prednisone equivalent dose (APED). Severe patients are treated with higher doses. The mortality benefit was observed in patients with oxygen saturation </=90%. Conclusions: Patients with greater comorbidity, severity, and inflammatory markers were those treated with CTs. In severe patients, there is a trend towards the use of higher doses. The mortality benefit was observed in patients with oxygen saturation </=90%