Discovery of 2-(1H-imidazo-2-yl)piperazines as a new class of potent and non-cytotoxic inhibitors of Trypanosoma brucei growth in vitro

The identification of a new series of growth inhibitors of Trypanosoma brucei rhodesiense, causative agent of Human African Trypanosomiasis (HAT), is described. A selection of compounds from our in-house compound collection was screened in vitro against the parasite leading to the identification of compounds with nanomolar inhibition of T. brucei growth. Preliminary SAR on the hit compound led to the identification of compound 34 that shows low nanomolar parasite growth inhibition (T. brucei EC₅₀ 5?nM), is not cytotoxic (HeLa CC₅₀?>?25,000?nM) and is selective over other parasites, such as Trypanosoma cruzi and Plasmodium falciparum (T. cruzi EC₅₀ 8120?nM, P. falciparum EC₅₀ 3624?nM).     

Prosystemin,a prohormone that modulates plant defense barriers,is an intrinsically disordered protein

Prosystemin, originally isolated from Lycopersicon esculentum, is a tomato pro‐hormone of 200 aminoacid residues which releases a bioactive peptide of 18 aminoacids called Systemin. This signaling peptide is involved in the activation of defense genes in solanaceous plants in response to herbivore feeding damage. Using biochemical, biophysical and bioinformatics approaches we characterized Prosystemin, showing that it is an intrinsically disordered protein possessing a few secondary structure elements within the sequence. Plant treatment with recombinant Prosystemin promotes early and late plant defense genes, which limit the development and survival of Spodoptera littoralis larvae fed with treated plants.     

Ecological comparison between duckweeds in central Italy: The invasive Lemna minuta vs the native L. minor

The American duckweed Lemna minuta shows an invasive behaviour in Europe, causing weed problems in aquatic habitats there. Few studies addressed this species’ ecological requirements for a suitable establishment in a site. In this paper, L. minuta populations were analysed through field surveys so as (1) to define the autoecology of this duckweed as regards the main environmental factors characterizing invaded habitats, and (2) to identify possible overlaps/differences in ecological requirements between the alien L. minuta and the common native L. minor, with which it is often associated and in direct competition. The occurrence/abundance of the two species and environmental data were collected from 41 wetlands in central Italy. Currently, L. minuta is more common and abundant than L. minor in the study-area, despite its recent arrival there (2007). The two species have a partially overlapped autoecology. However, L. minuta differs from L. minor since it occurs in waters which are less alkaline, slightly less warm, and richer in nitrates. It shows tolerance for environmental conditions which are limiting for most of macrophytes, including L. minor, such as high shading and low water oxygenation. This enables L. minuta to increase its invasion potentiality and thus to enlarge its distribution area.     

Effects of Self‐Conditioning Techniques (Self‐Hypnosis) in Promoting Weight Loss in Patients with Severe Obesity: A Randomized Controlled Trial

Objective

The usefulness of the rapid‐induction techniques of hypnosis as an adjunctive weight‐loss treatment has not been defined. This randomized controlled trial evaluated whether self‐conditioning techniques (self‐hypnosis) added to lifestyle interventions contributed to weight loss (primary outcome), changes in metabolic and inflammatory variables, and quality of life (QoL) improvement (secondary outcomes) in severe obesity.

Methods

Individuals (with BMI = 35‐50 kg/m²) without organic or psychiatric comorbidity were randomly assigned to the intervention (n = 60) or control arm (n = 60). All received exercise and behavioral recommendations and individualized diets. The intervention consisted of three hypnosis sessions, during which self‐hypnosis was taught to increase self‐control before eating. Diet, exercise, satiety, QoL, anthropometric measurements, and blood variables were collected and measured at enrollment and at 1 year (trial end).

Results

A similar weight loss was observed in the intervention (?6.5 kg) and control (?5.6 kg) arms (β = ?0.45; 95% CI: ?3.78 to 2.88; P = 0.79). However, habitual hypnosis users lost more weight (?9.6 kg; β = ?10.2; 95% CI: ?14.2 to ?6.18; P < 0.001) and greatly reduced their caloric intake (?682.5 kcal; β = ?643.6; 95% CI: ?1064.0 to ?223.2; P = 0.005) in linear regression models. At trial end, the intervention arm showed lower C‐reactive protein values (β = ?2.55; 95% CI: ?3.80 to ?1.31; P < 0.001), higher satiety (β = 19.2; 95% CI: 7.71‐30.6; P = 0.001), and better QoL (β = 0.09; 95% CI: 0.02‐0.16; P = 0.01).

Conclusions

Self‐hypnosis was not associated with differences in weight change but was associated with improved satiety, QoL, and inflammation. Indeed, habitual hypnosis users showed a greater weight loss.

     

Molecular and cellular basis of ornithine δ-aminotransferase deficiency caused by the V332M mutation associated with gyrate atrophy of the choroid and retina

Gyrate atrophy (GA) is a rare recessive disorder characterized by progressive blindness, chorioretinal degeneration and systemic hyperornithinemia. GA is caused by point mutations in the gene encoding ornithine δ-aminotransferase (OAT), a tetrameric pyridoxal 5′-phosphate-dependent enzyme catalysing the transamination of l-ornithine and α-ketoglutarate to glutamic–γ-semialdehyde and l-glutamate in mitochondria. More than 50 OAT variants have been identified, but their molecular and cellular properties are mostly unknown. A subset of patients is responsive to pyridoxine administration, although the mechanisms underlying responsiveness have not been clarified. Herein, we studied the effects of the V332M mutation identified in pyridoxine-responsive patients. The Val332-to-Met substitution does not significantly affect the spectroscopic and kinetic properties of OAT, but during catalysis it makes the protein prone to convert into the apo-form, which undergoes unfolding and aggregation under physiological conditions. By using the CRISPR/Cas9 technology we generated a new cellular model of GA based on HEK293 cells knock-out for the OAT gene (HEK-OAT_KO). When overexpressed in HEK-OAT_KO cells, the V332M variant is present in an inactive apodimeric form, but partly shifts to the catalytically-competent holotetrameric form in the presence of exogenous PLP, thus explaining the responsiveness of these patients to pyridoxine administration. Overall, our data represent the first integrated molecular and cellular analysis of the effects of a pathogenic mutation in OAT. In addition, we validated a novel cellular model for the disease that could prove instrumental to define the molecular defect of other GA-causing variants, as well as their responsiveness to pyridoxine and other putative drugs.     

Differential toxicity of TAR DNA‐binding protein 43 isoforms depends on their submitochondrial localization in neuronal cells

TAR DNA ‐binding protein 43 (TDP ‐43) is an RNA ‐binding protein and a major component of protein aggregates found in amyotrophic lateral sclerosis and several other neurodegenerative diseases. TDP ‐43 exists as a full‐length protein and as two shorter forms of 25 and 35 kD a. Full‐length mutant TDP ‐43s found in amyotrophic lateral sclerosis patients re‐localize from the nucleus to the cytoplasm and in part to mitochondria, where they exert a toxic role associated with neurodegeneration. However, induction of mitochondrial damage by TDP ‐43 fragments is yet to be clarified. In this work, we show that the mitochondrial 35 kD a truncated form of TDP ‐43 is restricted to the intermembrane space, while the full‐length forms also localize in the mitochondrial matrix in cultured neuronal NSC ‐34 cells. Interestingly, the full‐length forms clearly affect mitochondrial metabolism and morphology, possibly via their ability to inhibit the expression of Complex I subunits encoded by the mitochondrial‐transcribed mRNA s, while the 35 kD a form does not. In the light of the known differential contribution of the full‐length and short isoforms to generate toxic aggregates, we propose that the presence of full‐length TDP ‐43s in the matrix is a primary cause of mitochondrial damage. This in turn may cause oxidative stress inducing toxic oligomers formation, in which short TDP ‐43 forms play a major role.

     

Stimulation of laccases from Trametes pubescens: Use in dye decolorization and cotton bleaching

The production of laccases from Trametes pubescens was investigated along with the role of nutrients and elicitors. Copper proved to be a fundamental inducer, although productivity yields were consistently enhanced only in the presence of additional compounds (textile dyes). Using a central composite design, the optimal culture condition was examined, by taking into consideration the three distinct variables and their combinatorial effect. The 290?U?ml^?1 of laccases were produced after setting nitrogen, copper, and reactive blue 19 concentration; in a bioreactor, activity recovery was lower (90?U?ml^?1) and pellet morphology was different. The activity of the laccase crude extract was maximal at 60°C and stable for 14?h at 50°C and for 2 months at pH 6 and room temperature. The biotechnological potential was assessed, confirming the capacity to decolorize single or mixed solutions of textile dyes and to enhance the whitening yield of raw cotton fibers, working in synergism with the conventional H₂O₂-based method.