The effect of polyphenols and vitamin E on the antioxidant status and meat quality of broiler chickens exposed to high temperature

The aim of this study was to determine the effect of a polyphenol product (PP) (Proviox) and vitamin E on the antioxidant status and meat quality of broiler chickens exposed to high temperature. The experimental materials comprised 120 ROSS 308 broilers (6 treatments, 10 replications, 2 birds per replication). Dietary supplementation with vitamin E and PP was applied in the following experimental design: group I (negative control) – without supplementation; group II (positive control) – without supplementation; group III – supplementation with 100 mg vitamin E/kg; group IV – 200 mg vitamin E/kg; group V – 100 mg vitamin E/kg and 100 mg PP/kg; group VI – 200 mg PP/kg. In groups II–VI, broiler chickens aged 21–35 d were exposed to increased temperature (34°C for 10 h daily). In chickens exposed to high temperature, dietary supplementation with antioxidants, mostly PP, improved growth performance parameters, including body weight, body weight gain and feed intake until 28 d of age. Vitamin E added to broiler chicken diets at 200 mg/kg and vitamin E combined with PP was most effective in improving the total antioxidant status of birds, enhancing blood antioxidant enzyme activities and increasing vitamin E concentrations in the liver and breast muscles. Broilers fed diets supplemented with 200 mg/kg of vitamin E alone and vitamin E in combination with PP were characterised by a higher percentage content of breast muscles in the carcass. Dietary supplementation with antioxidants improved the water-holding capacity of meat, reduced natural drip loss and increased the crude ash content of meat. The breast muscles of chickens fed diets supplemented with PP had a lower contribution of yellowness. The breast muscles of chickens receiving diets with 100 mg vitamin E/kg(group III) and diets supplemented with PP (groups V and VI) were characterised by the highest concentrations of polyunsaturated fatty acids. The PP can be a valuable component of diets for broiler chickens exposed to high temperature.     

Design and visualization of second‐generation cyanoisoindole‐based fluorescent strigolactone analogs

Strigolactones (SLs) are a family of terpenoid allelochemicals that were recognized as plant hormones only a decade ago. They influence a myriad of both above‐ and below‐ground developmental processes, and are an important survival strategy for plants in nutrient‐deprived soils. A rapidly emerging approach to gain knowledge on hormone signaling is the use of traceable analogs. A unique class of labeled SL analogs was constructed, in which the original tricyclic lactone moiety of natural SLs is replaced by a fluorescent cyanoisoindole ring system. Biological evaluation as parasitic seed germination stimulant and hypocotyl elongation repressor proved the potency of the cyanoisoindole strigolactone analogs (CISAs) to be comparable to the commonly accepted standard GR24. Additionally, via a SMXL6 protein degradation assay, we provided molecular evidence that the compounds elicit SL‐like responses through the natural signaling cascade. All CISAs were shown to exhibit fluorescent properties, and the high quantum yield and Stokes shift of the pyrroloindole derivative CISA‐7 also enabled in vivo visualization in plants. In contrast to the previously reported fluorescent analogs, CISA‐7 displays a large similarity in shape and structure with natural SLs, which renders the analog a promising tracer to investigate the spatiotemporal distribution of SLs in plants and fungi.     

Redirecting the lipid metabolism of the yeast Starmerella bombicola from glycolipid to fatty acid production

Journal of Industrial Microbiology & Biotechnology - Free fatty acids are basic oleochemicals implemented in a range of applications including surfactants, lubricants, paints, plastics, and...     

Conformational solution studies of the SDS micelle-bound 11-28 fragment of two Alzheimer's beta-amyloid variants (E22K and A21G) using CD, NMR, and MD techniques

The beta-amyloid (Abeta) is the major peptide constituent of neuritic plaques in Alzheimer's disease (AD) and its aggregation is believed to play a central role in the pathogenesis of the disease. Naturally occurring mutations resulting in changes in the Abeta sequence (pos. 21-23) are associated with familial AD-like diseases with extensive cerebrovascular pathology. It was proved that the mutations alter the aggregation ability of Abeta and its neurotoxicity. Among five mutations at positions 21-23 there are two mutations with distinct clinical characteristics and potentially distinct pathogenic mechanism-the Italian (E22K) and the Flemish (A21G) mutations. In our studies we have examined the structures of the 11-28 fragment of the Italian and Flemish Abeta variants. The fragment was chosen because it has been shown to be the most important for amyloid fibril formation. The detailed structure of both variants Abeta(11-28) was determined using CD, 2D NMR, and molecular dynamics techniques under water-SDS micelle conditions. The NMR analysis revealed two distinct sets of proton resonances for the peptides. The studies of both peptides pointed out the existence of well-defined alpha-helical conformation in the Italian mutant, whereas the Flemish was found to be unstructured with the possibility of a bent structure in the central part of the peptide.     

Exploring the protein–protein interaction landscape in plants

Protein–protein interactions (PPIs) represent an essential aspect of plant systems biology. Identification of key protein players and their interaction networks provide crucial insights into the regulation of plant developmental processes and into interactions of plants with their environment. Despite the great advance in the methods for the discovery and validation of PPIs, still several challenges remain. First, the PPI networks are usually highly dynamic, and the in vivo interactions are often transient and difficult to detect. Therefore, the properties of the PPIs under study need to be considered to select the most suitable technique, because each has its own advantages and limitations. Second, besides knowledge on the interacting partners of a protein of interest, characteristics of the interaction, such as the spatial or temporal dynamics, are highly important. Hence, multiple approaches have to be combined to obtain a comprehensive view on the PPI network present in a cell. Here, we present the progress in commonly used methods to detect and validate PPIs in plants with a special emphasis on the PPI features assessed in each approach and how they were or can be used for the study of plant interactions with their environment.     

Quantitative examination of a perfusion microscope for the study of osmotic response of cells

The perfusion microscope was developed for the study of the osmotic response of cells. In this microscope, the cells are immobilized in a transparent chamber mounted on the stage and exposed to a variety of milieus by perfusing the chamber with solutions of different concentrations. The concentration of the supplied solution is controlled using two variable-speed syringe pumps, which supply an isotonic solution and a hypertonic solution. Before using this system to characterize the osmotic response of cells, the change in the concentration of NaCl solution flowing through the chamber is examined quantitatively using a laser interferometer and an image processing technique. The NaCl concentration is increased from an isotonic condition to a hypertonic condition abruptly or gradually at a given constant rate, and decreased from a hypertonic condition to an isotonic condition. It is confirmed that the concentration is nearly uniform in the cross direction at the middle of the chamber, and the change in the NaCl concentration is reproducible. The average rate of increase or decrease in the measured concentration agrees fairly well with the given rate when the concentration is changed gradually at a constant rate. The rate of the abrupt change is also determined to be the highest limit achieved by the present method. As the first application of using the perfusion microscope for biological studies, the volume change of cells after exposure to a hypertonic solution is measured. Then, the hydraulic conductivity of the cell membrane is determinedfrom the comparison of the volume change between the experiment and the theoretical estimation for the measured change in the NaCl concentration of the perfused solution.     

A comparison of biodegradation of phenol and homologous compounds by Pseudomonas vesicularis and Staphylococcus sciuri strains

Pseudomonas vesicularis and Staphylococcus sciuri were isolated as dominant strains from phenol-acclimated activated sludge. P. vesicularis was an efficient degrader of phenol, catechol, p-cresol, sodium benzoate and sodium salicylate in a single substrate system. Under similar conditions S. sciuri degraded only phenol and catechol from among aromatic compounds that were tested. Cell-free extracts of P. vesicularis grown on phenol (376 mg l(-1)), sodium benzoate (576 mg l(-1)) and sodium salicylate (640 mg l(-1)) showed catechol 2,3-dioxygenase activity initiating an extradiol (meta) splitting pathway. The degradative intradiol (ortho) pathway as a result of catechol 1,2-dioxygenase synthesis was induced in P. vesicularis cells grown on catechol (440 mg l(-1)) orp-cresol (432 mg l(-1)). Catechol 1,2-dioxygenase and the ortho-cleavage has been also reported in S. sciuri cells capable of degrading phenol (376 mg l(-1)) or catechol (440 mg l(-1)). In cell-free extracts of S. sciuri no meta-cleavage enzyme activity was detected. These results demonstrated that gram-positive S. sciuri strain was able to effectively metabolize some phenols as do many bacteria of the genus Pseudomonas but have a different capacity for degrading of these compounds.     

The key role of the energized state of Saccharomyces cerevisiae mitochondria in modulations of the outer membrane channels by the intermembrane space proteins

Mitochondria of the yeast Saccharomyces cerevisiae constitute a perfect model to study the outer membrane channel modulation as besides the TOM complex channel they contain only a single isoform of the VDAC channel and it is possible to obtain viable mutants devoid of the channel. Here, we report that the fraction of the intermembrane space isolated from wild type and the VDAC channel-depleted yeast mitochondria, except of the well-known VDAC channel modulator activity, displays also the TOM complex channel modulating activity as measured in the reconstituted system and with intact mitochondria. The important factor influencing the action of both modulating activities is the energized state of mitochondria. Moreover, the presence of the VDAC channel itself seems to be crucial to properties of the intermembrane space protein (s) able to modulate the outer membrane channels because in the case of intact mitochondria quantitative differences are observed between modulating capabilities of the fractions isolated from wild type and mutant mitochondria.     

Directionality of lambda plasmid DNA replication carried out by the heritable replication complex

There are two ‘pathways’ of replication of λ plasmids in Escherichia coli. One pathway requires the assembly of a new replication complex before replication and the second pathway is based on the activity of the replication complex inherited by one of two daughter plasmid copies after a preceding replication round. Such a phenomenon was postulated to occur also in other replicons, including Saccharomyces cerevisiae autonomously replicating sequences. Here we investigated directionality of λ plasmid replication carried out by the heritable and newly assembled replication complexes. Using two-dimensional agarose gel electrophoresis and electron microscopy we demonstrated that in both normal growth conditions and during the relaxed response to amino acid starvation (when only replication carried out by the heritable complex is possible), bidirectionally and undirectionally replicating plasmid molecules occurred in host cells in roughly equal proportions. The results are compatible with the hypothesis that both complexes (heritable and newly assembled) are equivalent.