Use of highly sensitive sublethal stress responses in the social amoeba Dictyostelium discoideum for an assessment of freshwater quality

In this work, the sensitivity of a battery of tests on the social amoeba Dictyostelium discoideum has been assessed within a freshwater toxicity study. The results obtained from the evaluation of survival and replication rate of D. discoideum were compared to those derived with a series of widely used tests for freshwater toxicity assessment, i. e. bioassays using Vibrio fischeri, Daphnia magna and Pseudokirchneriella subcapitata. The effects on sublethal endpoints, i.e. lysosomal membrane stability (LMS) and endocytotic rate, were analysed in conjunction with high-level endpoints to verify the potential to make a typical bioassay more sensitive. The field ecotoxicological investigation employing D. discoideum is part of a monitoring study assessing environmental quality of the Bormida River (Italy), subjected until recently to a chronic industrial pollution. The survey was carried out at several stations (upstream and downstream of a chemical factory outlet) in two different periods. In 2002, the results of chemical analyses performed on river water indicated no contamination. The ecotoxicological data obtained in this period showed that no evidence of biological effects was observed using V. fischeri and D. magna bioassays. In spite of the previous classical acute toxicity tests, significant differences in cell viability of D. discoideum were found. By analysing the effects measured on LMS and endocytotic rate, more relevant changes were observed for these sublethal stress biomarkers compared to survival. The chronic toxicity data showed significant changes in cell growth both of P. subcapitata and D. discoideum. Nevertheless, more sensitive and rapid responses were obtained when assessing the effects of exposure on D. discoideum. The chemical and ecotoxicological data obtained in 2006 indicated a full recovery of the quality of the river water (neither contamination nor toxicity found). Altogether, the results reported in this study underline that the use of a battery of biomarkers in conjunction with high-level endpoints may help follow the pollutant-induced stress syndrome in the organisms from early sublethal effects to starting mortality.     

Multiscale investigation of the functional properties of the human femur

The mechanical strength of human bones has often been investigated in the past. Bone failure is related to musculoskeletal loading, tissue properties, bone metabolism, etc. This is intrinsically a multiscale problem. However, organ-level performance in most cases is investigated as a separate problem, incorporating only part (if any) of the information available at a higher scale (body level) or at a lower one (tissue level, cell level). A multiscale approach is proposed, where models available at different levels are integrated. A middle-out strategy is taken: the main model to be investigated is at the organ level. The organ-level model incorporates as an input the outputs from the body-level (musculoskeletal loads), tissue-level (constitutive equations) and cell-level models (bone remodelling). In this paper, this approach is exemplified by a clinically relevant application: fractures of the proximal femur. We report how a finite-element model of the femur (organ level) becomes part of a multiscale model. A significant effort is related to model validation: a number of experiments were designed to quantify the model's sensitivity and accuracy. When possible, the clinical accuracy and the clinical impact of a model should be assessed. Whereas a large amount of information is available at all scales, only organ-level models are really mature in this perspective. More work is needed in the future to integrate all levels fully, while following a sound scientific method to assess the relevance and validity of such an integrated model.     

Numerical simulation of coherent transport in quantum wires for quantum computing

A solid-state implementation of a universal set of gates for quantum computation is proposed and analysed using a time-dependent 2D Schrödinger solver. The qubit is defined as the state of an electron propagating along a couple of quantum wires. The wires are suitably coupled through a potential barrier with variable height and/or width. It is shown how a proper design of the system allows the implementation of any one-qubit transformation. The two-qubit gate is realized through a Coulomb coupler able to entangle the quantum states of two electrons running in two wires of two different qubits. The simulated devices are GaAs—AlGaAs heterostructures that should be on the borderline of present semiconductor technology. An estimate of decoherence effects due to phonon scattering is also presented.     

Sugar‐Based Arylsulfonamide Carboxylates as Selective and Water‐Soluble Matrix Metalloproteinase‐12 Inhibitors

Matrix metalloproteinase‐12 (MMP‐12) can be considered an attractive target to study selective inhibitors useful in the development of new therapies for lung and cardiovascular diseases. In this study, a new series of arylsulfonamide carboxylates, with increased hydrophilicity resulting from conjugation with a β‐N‐acetyl‐d ‐glucosamine moiety, were designed and synthesized as MMP‐12 selective inhibitors. Their inhibitory activity was evaluated on human MMPs by using the fluorimetric assay, and a crystallographic analysis was performed to characterize their binding mode. Among these glycoconjugates, a nanomolar MMP‐12 inhibitor with improved water solubility, compound 3 [(R)‐2‐(N‐(2‐(3‐(2‐acetamido‐2‐deoxy‐β‐d ‐glucopyranosyl)thioureido)ethyl)biphenyl‐4‐ylsulfonamido)‐3‐methylbutanoic acid], was identified.     

Effect of long term dietary supplementation with plant extract on carcass characteristics meat quality and oxidative stability in pork

The effects of dietary supplementation in pigs with plant extract (PE) from Lippia spp., titrated in verbascoside (5 mg/kg feed), from weaning to slaughter (166 days), on carcass characteristics, meat quality, collagen characteristics, oxidative stability and sensory attributes of Longissimus dorsi (LD) muscle were examined. Ten pigs per treatment were slaughter at a live weight of 109.5 ± 1.4 kg. No influence on carcass characteristics, LD meat quality parameters and collagen characteristics were observed. Dietary PE increased (P < 0.001) α-tocopherol levels in LD muscle. Raw LD of pig fed PE showed lower (P < 0.001) lipid oxidation levels than controls. A reduction (P = 0.05) of fat odor and rancid flavor intensity in cooked LD muscle stored at 4 °C for 24 h was observed in the treated group. This study shows that PE is an effective antioxidant in pork meat, enhancing oxidative status and sensory attributes, without affecting other meat quality parameters.     

CRISPR/Cas9-Mediated Allele-Specific Disruption of a Dominant COL6A1 Pathogenic Variant Improves Collagen VI Network in Patient Fibroblasts

Collagen VI-related disorders are the second most common congenital muscular dystrophies for which no treatments are presently available. They are mostly caused by dominant-negative pathogenic variants in the genes encoding α chains of collagen VI, a heteromeric network forming collagen; for example, the c.877G>A; p.Gly293Arg COL6A1 variant, which alters the proper association of the tetramers to form microfibrils. We tested the potential of CRISPR/Cas9-based genome editing to silence or correct (using a donor template) a mutant allele in the dermal fibroblasts of four individuals bearing the c.877G>A pathogenic variant. Evaluation of gene-edited cells by next-generation sequencing revealed that correction of the mutant allele by homologous-directed repair occurred at a frequency lower than 1%. However, the presence of frameshift variants and others that provoked the silencing of the mutant allele were found in >40% of reads, with no effects on the wild-type allele. This was confirmed by droplet digital PCR with allele-specific probes, which revealed a reduction in the expression of the mutant allele. Finally, immunofluorescence analyses revealed a recovery in the collagen VI extracellular matrix. In summary, we demonstrate that CRISPR/Cas9 gene-edition can specifically reverse the pathogenic effects of a dominant negative variant in COL6A1.