β-Cyclodextrin polymer nanoparticles as carriers for doxorubicin and artemisinin: a spectroscopic and photophysical study

The association of doxorubicin (DOX) and artemisinin (ART) to a β-CyD-epichlorohydrin crosslinked polymer (pβ-CyD), organized in nanoparticles of ca. 15 nm size, was investigated in neutral aqueous medium by circular dichroism (CD), UV-vis absorption and fluorescence. The stability constants and the absolute CD spectra of the drug complexes were determined by global analysis of multiwavelength data from spectroscopic titrations. The polymer pβ-CyD proved able to disrupt the DOX dimer when the latter is the predominant form of DOX in solution. The spectroscopic and photophysical properties of the complexes evidenced an alcohol-like environment for ART and an improved inherent emission ability for DOX in the nanoparticle frame.     

Effect of conjugated linoleic acid on testosterone levels in vitro and in vivo after an acute bout of resistance exercise

The purposes of the present study were to investigate the effect of conjugated linoleic acid (CLA) supplementation on testosterone levels in vitro on a cell line derived from Leydig cells (R2C) and in vivo in the blood of physically active subjects before and after a resistance exercise bout. In vitro R2C cells were treated with different CLA concentrations (0-30 μM) for 24 and 48 hours. After treatment, supernatant media were tested to determine testosterone secretion. The CLA increased the testosterone secretion only after 48 hours. In vivo, 10 resistance-trained male subjects, in a double-blind placebo-controlled and crossover study design were randomized for 3 weeks of either 6 g·d?1 CLA or placebo. Blood was drawn pre and post each resistance exercise bout to determine the total testosterone and sex hormone-binding globulin (SHBG) levels. No significant differences were observed for total testosterone or SHBG pre and post each resistance exercise bout; although after the resistance exercise bouts, total testosterone increased moderately (effect size = moderate), whereas after CLA supplementation, there was a large increase in total testosterone (effect size = large). CLA supplementation induced an increase in testosterone levels in Leydig cells in vitro after 48 hours but not in vivo before and after a resistance exercise bout. These findings suggest that CLA supplementation may promote testosterone synthesis through a molecular pathway that should be investigated in the future, although this effect did not have an anabolic relevance in our in vivo model.     

Thyroid dysfunction in obese pre-pubertal children: oxidative stress as a potential pathogenetic mechanism

Although a relationship between obesity and hyperthyrotropinemia has been hypothesized in obese children, the underlying pathogenesis is not completely known. In the current cross-sectional study, we evaluated the thyroid function in a group of 80 obese pre-pubertal children compared to 41 healthy normal weight peers, exploring the possible association between hyperthyrotropinemia and oxidative stress. In all children, thyrotropin (TSH), free T4 (fT4), free T3 (fT3) and anti-thyroid antibodies were evaluated. Homeostatic model assessment of insulin resistance (HOMA-IR) level was evaluated as index of insulin resistance. We measured the endogenous secretory receptor for advanced glycation end products (esRAGE) and soluble RAGE (sRAGE) and the urinary prostaglandin F2α (PGF-2α) as markers of oxidative stress. We found that TSH levels were significantly higher in obese children than controls. TSH significantly correlated with body mass index-standard deviation score (BMI-SDS), HOMA-IR, PGF-2α, esRAGE and sRAGE. The multiple linear regression showed that in obese children HOMA-IR, PGF-2α, esRAGE and sRAGE were significantly related to TSH, independently of BMI-SDS, age and gender. In obese children, hyperthyrotropinemia could be detected already in pre-pubertal age. The increased oxidative stress might represent one of the key regulators of TSH levels, early in life.     

An All-Atom Model of the Structure of Human Copper Transporter 1

Human copper transporter 1 (hCTR1) is the major high affinity copper influx transporter in mammalian cells that also mediates uptake of the cancer chemotherapeutic agent cisplatin. A low resolution structure of hCTR1 determined by cryoelectron microscopy was recently published. Several protein structure simulation techniques were used to create an all-atom model of this important transporter using the low resolution structure as a starting point. The all-atom model provides new insights into the roles of specific residues of the N-terminal extracellular domain, the intracellular loop, and C-terminal region in metal ion transport. In particular, the model demonstrates that the central region of the pore contains four sets of methionine triads in the intramembranous region. The structure confirms that two triads of methionine residues delineate the intramembranous region of the transporter, and further identifies two additional methionine triads that are located in the extracellular N-terminal part of the transporter. Together, the four triads create a structure that promotes stepwise transport of metal ions into and then through the intramembranous channel of the transporter via transient thioether bonds to methionine residues. Putative copper-binding sites in the hCTR1 trimer were identified by a program developed by us for prediction of metal-binding sites. These sites correspond well with the known effects of mutations on the ability of the protein to transport copper and cisplatin.     

Differential weed seed removal in dryland cereals

Weeds persist in rain-fed cereal fields in NE Spain, despite intense herbicide use and high seed removal rates by granivorous harvester ants. Herbicide resistance is involved, but certain weed species also appear to escape seed removal by granivores. To identify the mechanisms involved, we measured seed removal rates (three fields in 2010) and the timing of seed shed (one field in 2009 and three fields in 2010) and used an existing model, which integrates short-term rates of seed shed, burial and removal, to estimate long-term seed removal rates. Averaged over years, fields and weed species, the long-term seed removal rate was estimated at 72?% (range 46?C100?%). Fifteen to 25?% of the seeds of Bromus diandrus avoided removal by being less attractive (low removal rates), and another 0?C29?% escaped through crop harvest, which made seeds inaccessible to granivores. Similarly, 20?C32?% of the Papaver rhoeas seeds escaped through crop harvest, while another 13?C17?% escaped by burial into the soil (small seed size). Other species, such as Galium spurium or Diplotaxis erucoides, had no means of avoiding seed removal by harvester ants. In particular, the more troublesome weeds, such as B. diandrus, P. rhoeas and L.?rigidum, combined herbicide resistance or tolerance with avoidance mechanisms against granivory.     

Longitudinal tracking of human fetal cells labeled with super paramagnetic iron oxide nanoparticles in the brain of mice with motor neuron disease

Stem Cell (SC) therapy is one of the most promising approaches for the treatment of Amyotrophic Lateral Sclerosis (ALS). Here we employed Super Paramagnetic Iron Oxide nanoparticles (SPIOn) and Hoechst 33258 to track human Amniotic Fluid Cells (hAFCs) after transplantation in the lateral ventricles of wobbler (a murine model of ALS) and healthy mice. By in vitro, in vivo and ex vivo approaches we found that: 1) the main physical parameters of SPIOn were maintained over time; 2) hAFCs efficiently internalized SPIOn into the cytoplasm while Hoechst 33258 labeled nuclei; 3) SPIOn internalization did not alter survival, cell cycle, proliferation, metabolism and phenotype of hAFCs; 4) after transplantation hAFCs rapidly spread to the whole ventricular system, but did not migrate into the brain parenchyma; 5) hAFCs survived for a long time in the ventricles of both wobbler and healthy mice; 6) the transplantation of double-labeled hAFCs did not influence mice survival.     

Stereocilia: the long and the short of it

Mutations in whirlin, a putative PDZ scaffold protein, have recently been shown to cause deafness and short cochlear hair cell stereocilia in whirler mice and recessive deafness (DFNB31) in humans. Through its PDZ domains, whirlin might organize a group of proteins into a functional complex required for stereocilia elongation. Identifying these protein partners will advance our understanding of the development of stereocilia and their function as mechanosensory organelles indispensable for normal hearing.     

Experimentally induced endosymbiont loss and re-acquirement in the hydrothermal vent bivalve Bathymodiolus azoricus

Invertebrates harbouring endosymbiotic chemoautotroph bacteria are widely distributed in a variety of reducing marine habitats, including deep-sea hydrothermal vents. In these species mechanisms of symbiont transmission are likely to be key elements of dispersal strategies that remained partially unresolved because the early life stages are not available for developmental studies. To study cessation and re-establishment of symbiosis in the host gill a laboratory experiment was conducted over 45 days in a controlled set-up (LabHorta) that endeavour re-creation of the hydrothermal vent chemical environment. Our animal model was the vent bivalve Bathymodiolus azoricus from the Menez Gwen vent site of the Mid Atlantic Ridge (MAR). Animals were exposed to conditions lacking inorganic S supply for 30 days, which is vital for their symbionts, and then re-acclimatized in sulphide-supplied seawater for an additional 15 days.Gradual disappearance of bacteria from the symbiont-bearing gill cells was observed in animals kept in seawater free of dissolved sulphide for up to 30 days, and was evidenced by histological, ultrastructural observations and Polymerase Chain Reaction tests. Following re-acclimatisation in S-supplied seawater, proliferation of sulphur-bacteria in the gill bacteriocytes confirms the functionality of our sulfide-feeding system in supporting chemoautotrophic symbionts. It may also indicate a horizontal endosymbiont acquisition, i.e. from the environment to the host by means of phagocytosis-like mechanism involving special “pit-like” structures on the apical cell membrane.The present work reports the first laboratory set-up successfully used to maintain the hydrothermal vent bivalve B. azoricus for prolonged periods of time by supplying inorganic sulphur as an energy source for its bacterial endosymbionts. Survival of symbiont bacteria is a critical factor influencing the host physiology and thus the methods reported here represent great potential for future studies of host-symbiont dynamics and for post-capture experimental investigations.