Spontaneous diabetes in BB rats: evidence for insulin dependent liver microsomal delta 6 and delta 5 desaturase activities

We studied linoleic acid delta 5 and dihomo-gamma-linolenic acid delta 5 desaturations, and fatty acid composition, of liver microsomes in the insulin-dependent spontaneously diabetic adult female BB rat. These desaturations were defective along the normo- and hyper-glycemic period and restored during the hypoglycemic period which followed the insulin injection to the diabetic rats. The fatty acid composition of BB rats microsomes was not consistent with the desaturase activities at the different periods of glycemia, probably because other factors than desaturation impairments were involved in the evolution of fatty acid composition.     

Effects of two sodium salts on fatty acid and essential oil composition of basil (Ocimum basilicum L.) leaves

The effects of two sodium salts on growth, fatty acids, and essential oil compositions were investigated in a medicinal and aromatic plant, Ocimum basilicum cultivated in hydroponic medium. Plants were subjected to an equimolar concentration of Na₂SO₄ (25 mM) and NaCl (50 mM) for 15 days. Our results showed that leaf growth rate was more depressed by 25 mM Na₂SO₄ than by 50 mM NaCl. The total fatty acid contents did not show any change in plants. α-Linolenic, palmitic, and linoleic acids were the major fatty acids. The identification of basil leaf fatty acids has not been previously studied and this work revealed the predominance of polyunsaturated fatty acids. Under both salts, leaf fatty acid composition remained unchanged. Regarding the essential oil yield, it decreased significantly by 28 % under 25 mM Na₂SO₄ and showed an increase by 27 % under 50 mM NaCl. The major volatile compound in leaves was linalool with 34.3 % of total essential oil constituents, followed by eugenol (19.8 %), 1.8-cineole (14.4 %) and methyl eugenol (5.2 %). Further, levels of eugenol and methyl eugenol were most modulated by salt, and the negative correlation between these two compounds reflects the stimulation of O-methyltransferase activity under both salts.     

Socioeconomic Factors Drive Fire-Regime Variability in the Mediterranean Basin

In recent decades, fires in Mediterranean Europe have become larger and more frequent. This trend has been driven by socioeconomic changes that have generated rural depopulation and changes in traditional land use. Within the Mediterranean Basin, the most contrasting socioeconomic conditions are found by comparing southern European with North African countries, and thus our hypothesis is that this difference generates contrasting fire regimes between the two regions. Specifically, we predict that current fire regimes in Mediterranean Africa resemble past fire regimes in the Mediterranean Europe when rural activities dominated the landscape. To test our hypothesis, we compared fire statistics from the western Rif (northern Morocco, 1988–2015) and from Valencia (eastern Spain, 1880–2014). The results suggest that the Rif has a typical Mediterranean fire regime with fires occurring in the hot, dry summer season. However, fires are very small and the annual proportion of burnt area is very low, compared to the current regime in Valencia (post-1970s). The current Rif fire size class distribution matches the fire regime in Valencia prior to the 1970s before the collapse of the rural population and when fires were fuel-limited. The shift in the recent decades in fire regime observed in different countries of the Mediterranean Europe (from small, fuel-limited fires to drought-driven fires) can be identified when moving from the southern to the northern rim of the basin. That is, most spatial and temporal variability in fire regimes of the Mediterranean Basin is driven by shifts in the amounts of fuel and continuity imposed by changes in socioeconomic drivers.     

Variability in the 11S globulin fraction of seed storage proteins ofHelianthus (Asteraceae)

The seed storage globulins from sixHelianthus and four hybrids were studied using mono and bidimensional gel SDS electrophoresis (+ 2 mercaptoethanol). The polypeptide composition of each subunit was determined. Different pairs are specifically expressed according to the species studied. Three typical patterns were discriminated. All the studied species exhibit five subunits: two of them are expressed in all the species (₁₁ and ₂₂). The subunit corresponding to the ₁₁ pair is present inH. petiolaris and in the three populations ofH. annuus studied. The _2b2 pair is common toH. annuus andH. argophyllus. H. petiolaris presents two specific _2a2 and ₄₄ pairs andH. annuus a specific ₃₃ pair. InH. argophyllus _{11 33} or ₄₄ are never observed but are replaced by ₁₃ and ₃₁ pairs. Some globulins, poorly represented, are of forms but present chains of higher molecular weights (in the range 54–56 kDa). Expressing variations in the banding patterns between these species by the use of a similarity index reveals complete identity between the three populations ofH. annuus. Identity between the twoH. petiolaris studied is also observed.H. annuus andH. argophyllus appear to be closer to each other thanH. petiolaris concerning the seed storage globulins.     

Homozygous <Emphasis Type="Italic">KCNMA1</Emphasis> mutation as a cause of cerebellar atrophy,developmental delay and seizures

Dominant gain-of-function mutations of the KCNMA1 gene, encoding the pore-forming subunit of the large conductance voltage- and Ca²⁺-activated K+ channel, have been described in a few patients with the syndrome of epilepsy, paroxysmal dyskinesias and developmental delay. In this report, we describe the loss-of-function phenotype of this newly described disease gene. In two siblings from a consanguineous family with epilepsy, developmental delay and severe cerebellar atrophy, combined exome/autozygome analysis identified a homozygous frameshift duplication in KCNMA1 (c.2026dupT; p. (Tyr676 Leufs^*7)) in both children. Our report defines a novel autosomal recessive KCNMA1-related epileptic phenotype that encompasses cerebellar atrophy without paroxysmal dyskinesia, and highlights the sensitivity of the developing brain to both increased and decreased activity of the KCNMA1-encoded channels.     

The compositional properties of human genes

Summary The present work represents the first attempt to study in greater detail previously proposed compositional correlations in genomes, based on a body of additional data relating to gene localizations as well as to extended flanking sequences extracted from gene banks. We have investigated the correlations that exist between (1) the GC levels of exons of human genes, and (2) the GC levels of either intergenic sequences or introns associated with the genes under consideration. In both cases, linear relationships with slopes close to unity were found. The similarity of the linear relationships indicates similar GC levels in intergenic sequences and introns located in the same isochores. Moreover, both intergenic sequences and introns showed GC levels 5–10% lower than the corresponding exons. The above findings considerably strengthen the previously drawn conclusion that coding and noncoding sequences (both inter- and intragenic) from the same isochores of the human genome are compositionally correlated. In addition, we find linear correlations between the GC levels of codon positions and of the intergenic sequences or introns associated with the corresponding genes, as well as among the GC levels of codon positions of genes.     

Large intra-individual variability of plasma cytokines in healthy young men: a two 24-h study over a month

Cytokine levels in blood are not yet fully considered as biomarkers for disease even if some significant progresses have been made in linking certain cytokines to some diseases. The aim of this study was to look for the stability of some cytokines in blood collected in two different days separated by one month. Fifteen healthy young men aged 20–30 years were selected for this study. Each subject participated in two 24-h sessions spaced a month apart. Blood sample was taken at 11:00, 17:00, 22:00, 01:00, 04:00, 06:00, and 08:00. Concentrations of interleukin-6, interleukin-1-receptor antagonist, soluble IL-2 receptor, interleukin-1 beta, and interleukin-2 were measured in serum. The circadian pattern of each variable was compared between the two days. The results show that there is no reliability for the measured cytokines. This study shows that cytokine levels measured in blood are neither reliable variables nor considered as stable markers in healthy subjects.     

Effect of sodium loading (3% NaCl) on arachidonic acid biosynthesis in rat liver microsomes.

Sodium loading increases arachidonic acid (AA) metabolism by way of the prostaglandins(PGs) from series 2. Its effect on AA biosynthesis remains unknown. The purpose of the present study was to investigate the influence of sodium loading on the fatty acid composition of liver and liver microsomes, and the liver microsomal delta-6 and delta-5 desaturations of linoleic acid (LA) into AA. We found a decrease of LA and dihomo-gamma-linolenic acid (DGLA) levels in liver total lipids of Wistar rats receiving hypernatriuretic drinking water (NaCl 3%) for 60 days. At the same time AA increased. DGLA decreased and AA increased in liver microsomal total lipids. 1(14) C-LA delta-6 desaturase and 2(14) C-DGLA delta-5 desaturase activities increased in liver microsomes. These results show that, in addition to its influence on the regulation of glomerular filtration, sodium loading is involved in the regulation of liver AA biosynthesis.     

A putative role for fusaric acid in biocontrol of the parasitic angiosperm Orobanche ramosa

Fusarium spp. are ubiquitous fungi found in soil worldwide as both pathogenic and nonpathogenic strains. The signals leading to disease or the absence of disease are poorly understood. We recently showed that fusaric acid (FA), a nonspecific toxin produced by most Fusarium spp., could elicit various plant defense responses at 100 nM without toxic effect. In this study, we checked for the effect of FA on root and root hairs, probable first site of contact between the fungi and the host. Large FA concentrations reduce root and root-hair growth and induce a rapid transient membrane hyperpolarization, followed by a large depolarization, due to the inhibition of H(+)-ATPase currents. Nanomolar concentrations of FA induced only an early transient membrane hyperpolarization of root hairs compatible with the induction of a signal transduction pathway. FA at 10(-7) M failed to induce salicylic acid- and jasmonic acid/ethylene-dependent defense-related genes but inhibited the germination of the angiosperm parasite Orobanche ramosa in contact of FA-pretreated Arabidopsis thaliana seedlings. These data suggest that FA at nontoxic concentrations could activate signal transduction components necessary for plant-defense responses that could contribute to biocontrol activity of Fusarium spp.     

DNA structures from phosphate chemical shifts

For B-DNA, the strong linear correlation observed by nuclear magnetic resonance (NMR) between the ³¹P chemical shifts (δP) and three recurrent internucleotide distances demonstrates the tight coupling between phosphate motions and helicoidal parameters. It allows to translate δP into distance restraints directly exploitable in structural refinement. It even provides a new method for refining DNA oligomers with restraints exclusively inferred from δP. Combined with molecular dynamics in explicit solvent, these restraints lead to a structural and dynamical view of the DNA as detailed as that obtained with conventional and more extensive restraints. Tests with the Jun-Fos oligomer show that this δP-based strategy can provide a simple and straightforward method to capture DNA properties in solution, from routine NMR experiments on unlabeled samples.