Comparison of pistachio hull essential oils from different Tunisian localities

Pistachio (Pistacia vera L.) fruit is well known for its oleaginous and edible seed. Less information is available about the hull constituted by the epicarp and the mesocarp. This part of the fruit contains an essential oil that can be valorized. Tunisia is one of the countries cultivating pistachio trees. This work presents essential oil composition of pistachio hulls (Mateur variety) from different geographical localities: Grombalia (North-East), Kairouan (Middle) and Sfax (Middle-East). Yields were more important in Sfax samples (0.53% on a dry weight basis). Alpha-terpinolene was the major compound for Grombalia fruits (35.7%), whereas Kairouan and Sfax samples where characterized by alpha-pinene (42.5 and 43.8% respectively). For all samples, monoterpene hydrocarbons predominated (more than 79.8% of the essential oil).     

Single nanoparticle photothermal tracking (SNaPT) of 5-nm gold beads in live cells

Tracking individual nano-objects in live cells during arbitrary long times is a ubiquitous need in modern biology. We present here a method for tracking individual 5-nm gold nanoparticles on live cells. It relies on the photothermal effect and the detection of the Laser Induced Scattering around a NanoAbsorber (LISNA). The key point for recording trajectories at video rate is the use of a triangulation procedure. The effectiveness of the method is tested against single fluorescent molecule tracking in live COS7 cells on subsecond timescales. We further demonstrate recordings for several minutes of AMPA receptors trajectories on the plasma membrane of live neurons. Single Nanoparticle Photothermal Tracking has the unique potential to record arbitrary long trajectory of membrane proteins using nonfluorescent nanometer-sized labels.     

Super-resolution Microscopy Approaches for Live Cell Imaging

By delivering optical images with spatial resolutions below the diffraction limit, several super-resolution fluorescence microscopy techniques opened new opportunities to study biological structures with details approaching molecular structure sizes. They have now become methods of choice for imaging proteins and their nanoscale dynamic organizations in live cells. In this mini-review, we describe and compare the main far-field super-resolution approaches that allow studying endogenous or overexpressed proteins in live cells.     

Genes coding for transcription factors involved in stem cell maintenance are repressed by TGF-β and downstream of Slug/Snail2 in COPD bronchial epithelial progenitors

Molecular Biology Reports - Basal stem/progenitor cells of airway epithelium from chronic obstructive pulmonary disease (COPD) patients have a decrease in differentiation and self-renewal...     

Nitrogen effects on proteins, chlorophylls and fatty acids during the growth of Arthrospira platensis

Spirulina platensis (=Arthrospira platensis) is a tunisian strain which has been isolated for the first time in Oued Essed (Sousse, Sidi Bou Ali). Biomass evolution, proteins, chlorophylls and fatty acids composition of this alga were monitored by varying nitrogen concentrations in the culture medium. Nitrogen stress was provoked by adding sodium nitrate (NaNO3) in the culture medium with concentrations varying from 0 to 5 g/l. Results obtained showed that nitrogen depletion increased total proteins and total chlorophylls. The addition of NaNO3 (5g/l) led to an increase of total fatty acids amounts and modify fatty acids composition. Optimal quantities of palmitic, gamma -linolenic and oleic acids were obtained with NaNO3 free-cultures. Thus, the tunisian strain has valuable biological substances, worthy to determine the optimal conditions for its propagation.     

Transport of fibroblast growth factor 2 in the pericellular matrix is controlled by the spatial distribution of its binding sites in heparan sulfate

The heparan sulfate (HS) chains of proteoglycans are a key regulatory component of the extracellular matrices of animal cells, including the pericellular matrix around the plasma membrane. In these matrices they regulate transport, gradient formation, and effector functions of over 400 proteins central to cell communication. HS from different matrices differs in its selectivity for its protein partners. However, there has been no direct test of how HS in the matrix regulates the transport of its partner proteins. We address this issue by single molecule imaging and tracking in fibroblast pericellular matrix of fibroblast growth factor 2 (FGF2), stoichiometrically labelled with small gold nanoparticles. Transmission electron microscopy and photothermal heterodyne imaging (PHI) show that the spatial distribution of the HS-binding sites for FGF2 in the pericellular matrix is heterogeneous over length scales ranging from 22 nm to several μm. Tracking of individual FGF2 by PHI in the pericellular matrix of living cells demonstrates that they undergo five distinct types of motion. They spend much of their time in confined motion (～110 nm diameter), but they are not trapped and can escape by simple diffusion, which may be slow, fast, or directed. These substantial translocations (μm) cover distances far greater than the length of a single HS chain. Similar molecular motion persists in fixed cells, where the movement of membrane PGs is impeded. We conclude that FGF2 moves within the pericellular matrix by translocating from one HS-binding site to another. The binding sites on HS chains form non-random, heterogeneous networks. These promote FGF2 confinement or substantial translocation depending on their spatial organisation. We propose that this spatial organisation, coupled to the relative selectivity and the availability of HS-binding sites, determines the transport of FGF2 in matrices. Similar mechanisms are likely to underpin the movement of many other HS-binding effectors.     

Synthesis and hydration properties of pH-sensitive p(HEMA)-based hydrogels containing 3-(trimethoxysilyl)propyl methacrylate

An amphiphilic hydrogel network was synthesized from a cross-linked poly(2-hydroxyethyl methacrylate) backbone copolymerized with the monomers 3-(trimethoxysilyl)propyl methacrylate (PMA) and dimethylaminoethyl methacrylate (DMAEMA) using tetraethylene glycol diacrylate (TEGDA) as cross-linker and using the radical initiator system comprising N,N,N',N'-tetramethylethylenediamine and ammonium peroxydisulfate. The degree of hydration of hydrogel slabs was investigated as functions of varying monomer compositions and cross-link density and as a function of pH and ionic strength of the bathing medium. As much as a 45% increase in hydration was observed for hydrogels containing 15 mol % DMAEMA upon reducing the pH of the bathing medium from 8.0 to 2.0. This confirms the pH-modulated swelling of amine-containing hydrogels. Increasing the concentration of TEGDA cross-linker from 3 to 12 mol % in a 10 mol % DMAEMA-containing hydrogel resulted in only a 10% reduction in the degree of hydration of the gel. There was, however, a 40-50% reduction in the degree of hydration of a 15 mol % DMAEMA hydrogel upon increasing the molar composition of PMA from 0 up to 20 mol %. The presence of PMA confers hydrophobic character that reduces hydration and introduces additional cross-links that reduce network mesh size. The water content of the hydrogel was consistently higher in buffers of lower ionic strength. The reversible pH-dependent swelling observed in these studies, along with the control of cross-link density afforded by the PMA component, endows these biocompatible materials with potential for use in pH-controlled drug delivery of more hydrophobic drugs and present new compositions for in vitro and in vivo biocompatibility studies.     

Enantiomeric separation of drugs and herbicides on a beta-cyclodextrin-bonded stationary phase.

A chemically bonded beta-cyclodextrin chiral stationary phase for HPLC was prepared in a "one pot" process by the reaction of a phenylated beta-cyclodextrin with silica gel. Various racemic analytes such as drugs (aminoalcohol adrenergic beta-blockers, benzodiazepine anxiolytics, arylpropionic acid antiinflammatory agents) and herbicides (aryloxypropionic acids and esters) were separated on the prepared material. The column showed good chiral recognition ability for most of the solutes tested when using heptane and either 2-propanol or chloroform as organic mobile phase modifiers.     

Ectopic expression of Gcm1 induces congenital spinal cord abnormalities

Brief ectopic expression of Gcm1 in mouse embryonic tail bud profoundly affects the development of the nervous system. All mice from 5 independently derived transgenic lines exhibited either one or both of two types of congenital spinal cord pathologies: failure of the neural tube to close (spina bifida) and multiple neural tubes (diastematomyelia). Because the transgene is expressed only in a restricted caudal region and only for a brief interval (E8.5 to E13.5), there was no evidence of embryonic lethality. The dysraphisms develop during the period and within the zone of transgene expression. We present evidence that these dysraphisms result from an inhibition of neuropore closure and a stimulation of secondary neurulation. After transgene expression ceases, the spinal dysraphisms are progressively resolved and the neonatal animals, while showing signs of scarring and tissue resorption, have a closed vertebral column. The multiple spinal cords remain but are enclosed in a single spinal column as in the human diastematomyelia. The animals live a normal life time, are fertile and do not exhibit any obvious weakness or motor disabilities.     

Structure,electronic properties,and NBO and TD-DFT analyses of nickel(II), zinc(II), and palladium(II) complexes based on Schiff-base ligands

In this work we studied the structural and electronic properties of the metal–Schiff base complexes Ni\( {\mathrm{L}}_2^2 \) (1), Pd\( {\mathrm{L}}_2^1 \) (2), Zn\( {\mathrm{L}}_2^2 \) (3), and Ni\( {\mathrm{L}}_2^1 \)(4), where L¹ and L² are Schiff bases synthesized from salicylaldehyde and 2-hydroxy-5-methylbenzaldehyde, respectively. Natural bond analysis showed that in complexes 1 and 2, the metal ion coordinates to the ligands through electron donation from lone pairs on ligand nitrogen and oxygen atoms to s and d orbitals on the metal ion. In complex 3, metal–N and metal–O bonds are formed through charge transfer from the lone pairs on nitrogen and oxygen atoms to an s orbital of Zn. Dimethylation of the phenolate rings in the ligands decreases the energy gap and redshifts the spectrum of the nickel complex. The main absorptions observed were assigned on the basis of singlet-state transitions. The simulated spectra of the two complexes 1 and 2 are characterized by excited states with ligand-to-ligand charge-transfer (LLCT), metal-to-ligand charge-transfer (MLCT), ligand-to-metal charge-transfer (LMCT), and metal-centered (MC) character.

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Graphical abstract Geometric structure of the palladium complex.