Interaction between Alzheimer's Aβ(25–35) peptide and phospholipid bilayers: The role of cholesterol

AbstractThere is mounting evidence that the lipid matrix of neuronal cell membranes plays an important role in the accumulation of β-amyloid peptides into senile plaques, one of the hallmarks of Alzheimer's disease (AD). With the aim to clarify the molecular basis of the interaction between amyloid peptides and cellular membranes, we investigated the interaction between a cytotoxic fragment of Aβ(1–42), i.e., Aβ(25–35), and phospholipid bilayer membranes. These systems were studied by Electron Paramagnetic Resonance (EPR) spectroscopy, using phospholipids spin-labeled on the acyl chain. The effect of inclusion of charged phospholipids or/and cholesterol in the bilayer composition was considered in relation to the peptide/membrane interaction. The results show that Aβ(25–35) inserts in bilayers formed by the zwitterionic phospholipid dilauroyl phosphatidylcholine (DLPC), positioning between the outer part of the hydrophobic core and the external hydrophilic layer. This process is not significantly influenced by the inclusion of the anionic phospholipid phosphatidylglycerol (DLPG) in the bilayer, indicating the peptide insertion to be driven by hydrophobic rather than electrostatic interactions. Cholesterol plays a fundamental role in regulating the peptide/membrane association, inducing a membrane transition from a fluid-disordered to a fluid-ordered phase. At low cholesterol content, in the fluid-disordered phase, the insertion of the peptide in the membrane causes a displacement of cholesterol towards the more external part of the membrane. The crowding of cholesterol enhances its rigidifying effect on this region of the bilayer. Finally, the cholesterol-rich fluid-ordered membrane looses the ability to include Aβ(25–35)

Clinical evidences of urea at medium concentration.

Urea-based topical compounds at medium concentrations (15%-30%) represent useful dermatological agents for their humectant and keratolytic effects by enhancing stratum corneum hydration and by loosening epidermal keratin, respectively. The aim of this paper is to review the clinical evidences of the use of 15%-30% urea as single topical agent. Although limited evidence supports the use of these concentrations of urea in skin disorders characterised by xerosis and hyperkeratosis, in clinical practice they are largely used especially in xerosis of limited skin areas, in which the side effects are tolerable, or hyperkeratosis involving large or more sensitive (eg, face, genital region, etc) areas, in which higher concentration may be irritant. In addition, urea at medium concentrations is used in combination with other substances including topical antifungals as penetration enhancer

Physical and chemical properties of long-term salinized soils

In some areas, particularly in the Mediterranean regions, saline water is a source of water for crop irrigation. Consequently during the time, the use of this water may cause significant modifications of the soil physic-chemical properties and plant toxicity. The purpose of this investigation was to assess the variation of soil stability index and of ECe, ESP, pH, exchangeable potassium, bulk density, soil hydraulic conductivity and water retention curve (h(θ)), for a clay sandy soil, which was irrigated over 12 years with saline water. The soil stability index was evaluated by 2 methods: after wetting the sample (Water Stability Index = WSI) and without the pre-wetting step (Water Stability Dry Index = WSDI). The measures have been taken at three depths along the soil profile: 0-0.30, 0.30-0.60 and 0.60-0.90 m. The saline water was obtained by adding commercial sea salt to the irrigation water with the result of a final concentrations of 0.25 (2.5 g l-1), 0.5 (5 g l-1) and 1% (10 g l-1). A non-salinized control was also included. The increasing salinity of the irrigation water increased at all the depths ECe, ESP and pH, while exchangeable potassium decreased. Assessment of soil aggregates stability without samples pre-wetting (WSDI) allowed us to better discriminate among the different samples examined. Aggregate stability for each of the soil layers decreased at increasing salinity of the irrigation water. Long term salinization affected the aggregate stability of the deepest layers. The soil hydraulic conductivity decreased also, while bulk density increased. The shape of the soil water retention curve was also affected by salinity. In the salinized plots less water is relaxed within -150 ÷ -12 cm ψ range. The available water was reduced at increasing salinity. Irrigation with saline water on clay-sandy soils increases ECe, pH and ESP, all of which negatively affect the soil aggregate stability. Damage to the soil structure remarkably reduces the available water and soil hydraulic conductivity. The magnitude of these deleterious effects may increase through the years and in proportion to salt concentration in the irrigation water

Effects of the fertilizer added with dmpp on soil nitrous oxide emissions and microbial functional diversity

Agricultural sites contribute extensively to atmospheric emissions of climate-altering gases such as nitrous oxide. Several strategies have been considered to mitigate the impact of agriculture on climate, among these the utilization of fertilizers added with nitrification inhibitors such as DMPP (3,4-dimethylpyrazole phosphate) may represent a suitable solution. DMPP inhibits the growth and activity of ammonia-oxidizing microorganisms, particularly the ammonia-oxidizing bacteria, which are involved in N2O production. At present, little information is available on the effects of DMPP on the catabolic diversity of soil microbial community. In this study, the N2O emission by soil was performed by using the static chamber technique. The biological determinations of the microbial biomass carbon and the catabolic profile were assessed by measuring the substrate-induced respiration during the entire growing season of a potato crop under two nitrogen treatments: fertilization with and without DMPP. Our results did not show a clear mitigation of N2O emission by DMPP, even if a tendency to lower N2O fluxes in DMPP plots occurred when soil temperatures were lower than 20◦C. Conversely, DMPP deeply affected the microbial biomass and the catabolism of soil microorganisms, exerting a negative effect when it accumulated in excessive doses in the soil, limiting the growth and the capacity of soil microorganism communities to use different substrates

Native Arbuscular Mycorrhizal Fungi Characterization from Saline Lands in Arid Oases, Northwest China

Arbuscular mycorrhizal fungi (AMF) colonize land plants in almost every ecosystem, even in extreme conditions, such as saline soils. In the present work, we report the mycorrhizal capacity of rhizosphere soils collected in the dry desert region of the Minqin Oasis, located in the northwest of China (Gansu province), which is characterized by several halophytes. Lycium spp. and Peganum nigellastrum were used as trap plants in a greenhouse experiment to identify autochthonous AMF associated with the halophytes’ rhizospheres. Morphological observations showed the typical AMF structures inside roots. Twenty-six molecularly distinct AMF taxa were recovered from soil and root DNA. The taxonomical diversity mirrors the several AMF adapted to extreme environmental conditions, such as the saline soil of central China. Knowledge of the AMF associated with halophytes may contribute to select specific fungal isolates to set up agriculture strategies for protecting non-halophyte crop plants in saline soils

Amyotrophic Lateral Sclerosis and Multiple Sclerosis Overlap: A Case Report

The concurrence of amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS) is extremely rare. We reported the case of a 33-year-old woman with a past history of paresthesias at the right hand, who developed progressive quadriparesis with muscular atrophy of limbs and, finally, bulbar signs and dyspnea. Clinical and neurophysiologic investigations revealed upper and lower motor neuron signs in the bulbar region and extremities, suggesting the diagnosis of ALS. Moreover, magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) analysis demonstrated 3 periventricular and juxtacortical lesions, hyperintense in T2 and FLAIR sequences, and 3 liquoral immunoglobulin G (IgG) oligoclonal bands, consistent with diagnosis of primary progressive MS (PPMS). This unusual overlap of ALS and MS leads to the discussion of a hypothetical common pathological process of immunological dysfunction in these two disorders, although the role of immune response in ALS remains ambivalent and unclear

Understanding of historical masonry for conservation approaches: the contribution of Prof. Luigia Binda to research advancement

Prof. Luigia Binda was a Full Professor in Restoration at the School of Architecture of Politecnico di Milano. She began her career teaching building and construction techniques, then strengthening and reinforcement of masonry buildings and preservation of cultural heritage. L. Binda, in her long scientific activity, addressed her interest to historic masonry structures, with a strategic broad knowledge of the process and merging knowledge from different research fields. Thanks to her multidisciplinary attitude, a deep passion toward puzzling problems and a gentle approach, she was able to combine conservation and safety issues with a robust experimental knowledge of masonry behavior, giving an extraordinary impulse to the research into the experimental understanding, modelling, strengthening and preserving the cultural heritage. The paper shortly illustrates the main aspects of selected topics among the most outstanding contributions given by Prof. L. Binda in research, and describes the advancements made possible in many related fields, both academic and of professional practice. The title of each chapter starts with a typical sentence L. Binda used to remind people, which summarizes at a glance the importance of that specific aspect in the topic. In the authors view, it also implicitly indicates the innovative character of her insights and her extraordinary dedication to research

Size-Based Effects of Anthropogenic Ultrafine Particles on Lysosomal TRPML1 Channel and Autophagy in Motoneuron-like Cells

An emerging body of evidence indicates an association between anthropogenic particulate matter (PM) and neurodegeneration. Although the historical focus of PM toxicity has been on the cardiopulmonary system, ultrafine PM particles can also exert detrimental effects in the brain. However, only a few studies are available on the harmful interaction between PM and CNS and on the putative pathomechanisms

Symptomatic SARS-CoV-2 Reinfection in a Healthy Healthcare Worker in Italy Confirmed by Whole-Genome Sequencing

This study describes a case of SARS-CoV-2 reinfection confirmed by whole-genome sequencing in a healthy physician who had been working in a COVID-19 hospital in Italy since the beginning of the pandemic. Nasopharyngeal swabs were obtained from the patient at each presentation as part of routine surveillance. Nucleic acid amplification testing was performed on the two samples to confirm SARS-CoV-2 infection, and serological tests were used to detect SARS-CoV-2 IgG antibodies. Comparative genome analysis with whole-genome sequencing was performed on nasopharyngeal swabs collected during the two episodes of COVID-19. The first COVID-19 episode was in March 2020, and the second was in January 2021. Both SARS-CoV-2 infections presented with mild symptoms, and seroconversion for SARS-CoV-2 IgG was documented. Genomic analysis showed that the viral genome from the first infection belonged to the lineage B.1.1.74, while that from the second infection to the lineage B.1.177. Epidemiological, clinical, serological, and genomic analyses confirmed that the second episode of SARS-CoV-2 infection in the healthcare worker met the qualifications for “best evidence” for reinfection. Further studies are urgently needed to assess the frequency of such a worrisome occurrence, particularly in the light of the recent diffusion of SARS-CoV-2 variants of concer