Growth of Pleurotus ostreatus on wheat straw and wheat-grain-based media: biochemical aspects and preparation of mushroom inoculum

Mycelial growth, intracellular activity of proteases, laccases and β-1,3-glucanases, and cytoplasmic protein were evaluated in the vegetative phase of Pleurotus ostreatus grown on wheat straw and in wheat-grain-based media in Petri dishes and in bottles. The productivity of the wheat straw and wheat-grain-based spawn in cylindrical polyethylene bags containing 5 kg of chopped straw was also determined. We observed high activity of proteases and high content of intracellular protein in cultures grown on wheat straw. This suggests that the proteases are not secreted into the medium and that the protein is an important cellular reserve. On the contrary, cultures grown on wheat straw secreted laccases into the medium, which could be induced by this substrate. P. ostreatus grown on media prepared with a combination of wheat straw and wheat grain showed a high radial growth rate in Petri dishes and a high level of mycelial growth in bottles. The productivities of wheat straw and wheat-grain-based spawn were similar. Our results show that cheaper and more productive mushroom spawn can be prepared by developing the mycelium on wheat straw and wheat-grain-based substrates.     

Assessment of the relative contribution of asexual propagation in a population of the coral-excavating sponge Cliona delitrix from the Bahamas

Cliona delitrix is a very destructive coral-excavating sponge in Caribbean coral reef systems, particularly for Montastraea species. Little is known about how these excavating sponges propagate across coral reefs. In this study a hypothesis was tested that coral breakage caused by the bioeroding activity facilitates the asexual propagation of this sponge and in turn favors the spread of the most aggressive sponge genotypes. An allozyme analysis, involving 12 loci systems of 52 sponge individuals from a total of 13 Montastraea heads, found that no two sponges possessed identical multi-locus genotypes. Contrary to the pattern expected for fragmenting species, the incidence of clonality and asexual propagation at the population level was minimal. The lack of correlation between genetic and physical distances for the studied sponges also suggests that population maintenance appears to derive from larval dispersal, with a spatial range of dispersal larger than the average distance between the coral heads (10–10² m).     

The influence of AMPs from HaCaT keratinocytes on some bacteria strains derived from skin changes

The aim of this study was to evaluate antimicrobial activity of protein extracts from HaCaT cell line against bacterial strains, isolated from clinical materials, obtained from patients with clinical symptoms of acne (Propionibacterium acnes) and gas gangrene (Clostridium perfringens and Sterptococcus pyogenes). Reference strain of Staphylococcus aureus ATCC 25923 also was used. Protein extracts from cultured HaCaT cells were obtained by 3-fold freezing/defreezing cells in dry ice following by centrifugation and incubated with appropriate bacterial suspension (0.5 McFarland scale) during 6 and 24 hours. We observed time-depending and strain-depending activity of HaCaT--protein extract. Interestingly, high activity was demonstrated against strains of S. pyogenes and C. perfringens. Because of increasing bacterial resistance to antibiotics further studies in the field of antimicrobial peptides are required.     

Solution conformations of the antimetabolite 9-beta-D-xylofuranosyladenine and its 8-bromo analogue

An analysis has been made, with the aid of 1H NMR spectroscopy, of the solution conformation of the known antimetabolite, 9-beta-D-xylofuranosyladenine (xyloA), and of its 8-bromo analogue. For xyloA, the results point to a strong preference for the sugar ring of the conformation type N (C(3') endo), a relatively low population of the gauche-gauche rotamer of the exocyclic 5'-CH2OH, and a preference for the conformation anti about the glycosidic bond. For 8-bromo-xyloA, the preference for the type N conformation of the sugar ring is less marked, and the preferred conformation about the glycosidic bond is syn. The conformation of the sugar ring in the foregoing xylonucleosides consequently differs appreciably from that for the corresponding ribonucleosides, which adopt preferentially the type S (C(2')endo) and gauche-gauche conformations. Comparison with previously reported results for O'-methyl derivatives of xyloA points to the similarity in conformational properties of all of these. In contrast to arabinonucleosides with free 2' and 5' hydroxyls, the conformation of xyloA is relatively unaffected in strongly alkaline medium where the sugar hydroxyl(s) dissociate. Under these conditions, there is no formation of an intramolecular hydrogen bond such as might have been anticipated from X-ray diffraction studies in the solid state.     

Heritability of cortisol response to confinement stress in European sea bass dicentrarchus labrax

Background

In fish, the most studied production traits in terms of heritability are body weight or growth, stress or disease resistance, while heritability of cortisol levels, widely used as a measure of response to stress, is less studied. In this study, we have estimated heritabilities of two growth traits (body weight and length) and of cortisol response to confinement stress in the European sea bass.

Findings

The F1 progeny analysed (n = 922) belonged to a small effective breeding population with contributions from an unbalanced family structure of just 10 males and 2 females. Heritability values ranged from 0.54 (±0.21) for body weight to 0.65 (±0.22) for standard body length and were low for cortisol response i.e. 0.08 (±0.06). Genetic correlations were positive (0.94) between standard body length and body weight and negative between cortisol and body weight and between cortisol and standard body length (−0.60 and −0.55, respectively).

Conclusion

This study confirms that in European sea bass, heritability of growth-related traits is high and that selection on such traits has potential. However, heritability of cortisol response to stress is low in European sea bass and since it is known to vary greatly among species, further studies are necessary to understand the reasons for these differences.     

NMR studies of malaria 31P nuclear magnetic resonance of blood from mice infected with Plasmodium berghei

High resolution ³¹P-NMR has been used for the non-invasive observation of metabolites and metabolic rates in blood of normal mice and of mice infected with Plasmodium berghei, the causative agent of malaria. ³¹P-NMR was used to quantitate levels of 2,3-diphosphoglycerate in whole cells as a function of the degree of parasitemia and yielded good agreement with the results of enzymatic assays. The time-dependence of ³¹P metabolites was monitored in both normal and infected erythrocytes, greater rates of decay of 2,3-diphosphoglycerate being observed in malarial blood which correlate with the level of parasitemia. Very high metabolic rates of infected cells render measurement of intracellular pH unreliable on freshly drawn whole blood. When appropriate measures are taken to avoid this complication, no difference is observed in the intracellular pH of parasitized and non-parasitized erythrocytes from infected animals. In both normal and parasitized mice the intraerythrocytic pH is more acidic than that of the suspending medium by 0.15 pH unit at 25°C. Unlike free-living protozoa, the parasitic protozoan Plasmodium does not contain detectable levels of phosphonates or polyphosphates, in either whole cells or perchloric acid extracts thereof.     

Iterleukin 1 alpha is a marker of endothelial cellular senescent

Background  

The functional changes associated with endothelial senescence may be involved in human aging and age-related vascular disorders. Since the inflammatory cytokine interleukin (IL-)1 inhibits endothelial growth, we evaluated the expression of IL-1α, IL-1β and their antagonist, the IL-1 receptor antagonist (IL-1ra), in endothelial in vitro senescence and quiescence. We also examined the expression of IL-1α in human senescent and progeric fibroblasts.     

Characterization of the phase behavior of phosphonolipids in model and biological membranes by 31P-NMR

³¹P-NMR is used to characterize the phase behavior of phosphonolipids in both model and biological membranes. ($\text{1′,2′-}\text{Dipalmitoyl}\text{-sn-}\text{glyceryl)-2-aminoethylphosphonate}$ gives rise to static chemical shift tensor elements (?87, 5 and 63 ppm) which differ considerably from those reported for the analogous phospholipid, $\text{1,2-}\text{dipalmitoyl}\text{-sn-}\text{glycero-3-phosphoethanolamine}$ (?81, ?20 and 105 ppm). Phosphonolipid, as well as a mixture of phosphonolipid and $\text{1,2-}\text{dipalmitoyl}\text{-sn-}\text{glycero-3-phosphocholine}$, in aqueous dispersion gives rise to ³¹P spectra which may be interpreted in terms of lamellar structures. A mixture of phosphonolipid and egg phosphatidylethanolamine exhibits a bilayer-to-hexagonal phase transition with a concomitant decrease by one-half in the value of the ³¹P chemical shift anisotropies of both the phosphonate and phosphate resonances. The chemical shift anisotropy associated with phosphonolipid has been found to be consistently smaller than that observed for the analogous phospholipid. ³¹P-NMR spectra of total lipid extracts of Tetrahymena sp. indicate that both phospho- and phosphonolipids have a bilayer organization between ?20 and 20°C.     

Distributions of two recently inserted long interspersed elements of the L1 repetitive family at the Alb and beta h3 loci in wild mice populations

The presence of the L1 sequences, L1Md4 next to the pseudogene beta h3 and I12 found in the twelfth intron of the albumin gene, in certain strains of laboratory mice but not of others has led to the suggestion that these sequences were recent insertions into the Mus mus domesticus genome. To be sure that they are really recent insertions and not relics of an ancestral chromosome, we investigated the presence or absence of these sequences in populations of wild mice belonging to the semispecies M. m. domesticus and M. m. musculus as well as in other species of the genus Mus and in related murids. The sequence I12 in the albumin gene was found in 34% of the chromosomes of the wild mice belonging to M. m. domesticus and to a lesser extent (6%) in M. m. musculus. Of 114 M. m. domesticus chromosomes, L1Md4 was found in only nine, seven of which came from the same locality. Its presence was associated with the haplotype Hbbp, which is relatively rare in European populations of M. musculus. Since there was no evidence for the presence of these two L1 sequences in more distantly related species, we conclude that they are recent insertions in the M. musculus genome.