An in vivo drug screen in zebrafish reveals that cyclooxygenase 2-derived prostaglandin D2 promotes spinal cord neurogenesis

The study of neurogenesis is essential to understanding fundamental developmental processes and for the development of cell replacement therapies for central nervous system disorders. Here, we designed an in vivo drug screening protocol in developing zebrafish to find new molecules and signalling pathways regulating neurogenesis in the ventral spinal cord. This unbiased drug screen revealed that 4 cyclooxygenase (COX) inhibitors reduced the generation of serotonergic interneurons in the developing spinal cord. These results fitted very nicely with available single-cell RNAseq data revealing that floor plate cells show differential expression of 1 of the 2 COX2 zebrafish genes (ptgs2a). Indeed, several selective COX2 inhibitors and two different morpholinos against ptgs2a reduced the number of serotonergic neurons in the ventral spinal cord and led to locomotor deficits. Single-cell RNAseq data and different pharmacological manipulations further revealed that COX2-floor plate-derived prostaglandin D2 promotes neurogenesis in the developing spinal cord by promoting mitotic activity in progenitor cells. Rescue experiments using a phosphodiesterase-4 inhibitor suggest that intracellular changes in cAMP levels underlie the effects of COX inhibitors on neurogenesis and locomotion. Our study provides compelling in vivo evidence showing that prostaglandin signalling promotes neurogenesis in the ventral spinal cord.

Colloidal Chiral Carbon Dots: An Emerging System for Chiroptical Applications

Chiral CDots (c-CDots) not only inherit those merits from CDots but also exhibit chiral effects in optical, electric, and bio-properties. Therefore, c-CDots have received significant interest from a wide range of research communities including chemistry, physics, biology, and device engineers. They have already made decent progress in terms of synthesis, together with the exploration of their optical properties and applications. In this review, the chiroptical properties and chirality origin in extinction circular dichroism (ECD) and circularly polarized luminescence (CPL) of c-CDots is briefly discussed. Then, the synthetic strategies of c-CDots is summarized, including one-pot synthesis, post-functionalization of CDots with chiral ligands, and assembly of CDots into chiral architectures with soft chiral templates. Afterward, the chiral effects on the applications of c-CDots are elaborated. Research domains such as drug delivery, bio- or chemical sensing, regulation of enzyme-like catalysis, and others are covered. Finally, the perspective on the challenges associated with the synthetic strategies, understanding the origin of chirality, and potential applications is provided. This review not only discusses the latest developments of c-CDots but also helps toward a better understanding of the structure-property relationship along with their respective applications.

Use of patellofemoral digital twins for patellar tracking and treatment prediction: comparison of 3D models and contact detection algorithms

Introduction: Poor patellar tracking can result in painful contact pressures, patella subluxation, or dislocation. The use of musculoskeletal models and simulations in orthopedic surgeries allows for objective predictions of post-treatment function, empowering clinicians to explore diverse treatment options for patients. Although a promising approach for managing knee surgeries, the high computational cost of the Finite Element Method hampers its clinical usability. In anticipation of minimal elastic deformations in the involved bodies, the exploration of the Multibody Dynamics approach emerged as a viable solution, providing a computationally efficient methodology to address clinical concerns related to the knee joint. Methods: This work, with a focus on high-performance computing, achieved the simulation of the patellofemoral joint through rigid-body multibody dynamics formulations. A comparison was made between two collision detection algorithms employed in the simulation of contact between the patellar and femoral implants: a generic mesh-to-mesh collision detection algorithm, which identifies potential collisions between bodies by checking for proximity or overlap between their discretized mesh surface elements, and an analytical contact algorithm, which uses a mathematical model to provide closed-form solutions for specific contact problems, but cannot handle arbitrary geometries. In addition, different digital twins (3D model geometries) of the femoral implant were compared. Results: Computational efficiency was considered, and histories of position, orientation, and contact force of the patella during the motion were compared with experimental measurements obtained from a sensorized 3D-printed test bench under pathological and treatment scenarios. The best results were achieved through a purely analytical contact detection algorithm, allowing for clinical usability and optimization of clinical outcomes.

Why do lactic acid bacteria thrive in chain elongation microbiomes?

Efficient waste management is necessary to transition towards a more sustainable society. An emerging trend is to use mixed culture biotechnology to produce chemicals from organic waste. Insights into the metabolic interactions between community members and their growth characterization are needed to mediate knowledge-driven bioprocess development and optimization. Here, a granular sludge bioprocess for the production of caproic acid through sugar-based chain elongation metabolism was established. Lactic acid and chain-elongating bacteria were identified as the two main functional guilds in the granular community. The growth features of the main community representatives (isolate Limosilactobacillus musocae G03 for lactic acid bacteria and type strain Caproiciproducens lactatifermentans for chain-elongating bacteria) were characterized. The measured growth rates of lactic acid bacteria (0.051 ± 0.005 h-1) were two times higher than those of chain-elongating bacteria (0.026 ± 0.004 h-1), while the biomass yields of lactic acid bacteria (0.120 ± 0.005 g biomass/g glucose) were two times lower than that of chain-elongating bacteria (0.239 ± 0.007 g biomass/g glucose). This points towards differential growth strategies, with lactic acid bacteria resembling that of a r-strategist and chain-elongating bacteria resembling that of a K-strategist. Furthermore, the half-saturation constant of glucose for L. mucosae was determined to be 0.35 ± 0.05 g/L of glucose. A linear trend of caproic acid inhibition on the growth of L. mucosae was observed, and the growth inhibitory caproic acid concentration was predicted to be 13.6 ± 0.5 g/L, which is the highest reported so far. The pre-adjustment of L. mucosae to 4 g/L of caproic acid did not improve the overall resistance to it, but did restore the growth rates at low caproic acid concentrations (1-4 g/L) to the baseline values (i.e., growth rate at 0 g/L of caproic acid). High resistance to caproic acid enables lactic acid bacteria to persist and thrive in the systems intended for caproic acid production. Here, insights into the growth of two main functional guilds of sugar-based chain elongation systems are provided which allows for a better understanding of their interactions and promotes future bioprocess design and optimization.

Steerable isobutyric and butyric acid production from CO2 and H2 by Clostridium luticellarii

Clostridium luticellarii is a recently discovered acetogen that is uniquely capable of producing butyric and isobutyric acid from various substrates (e.g. methanol), but it is unclear which factors influence its (iso)butyric acid production from H2 and CO2 . We aimed to investigate the autotrophic metabolism of C. luticellarii by identifying the necessary growth conditions and examining the effects of pH and metabolite levels on product titers and selectivity. Results show that autotrophic growth of C. luticellarii requires the addition of complex nutrient sources and the absence of shaking conditions. Further experiments combined with thermodynamic calculations identified pH as a key parameter governing the direction of metabolic fluxes. At circumneutral pH (~6.5), acetic acid is the sole metabolic end product but C. luticellarii possesses the unique ability to co-oxidize organic acids such as valeric acid under high H2 partial pressures (>1 bar). Conversely, mildly acidic pH (≤5.5) stimulates the production of butyric and isobutyric acid while partly halting the oxidation of organic acids. Additionally, elevated acetic acid concentrations stimulated butyric and isobutyric acid production up to a combined selectivity of 53 ± 3%. Finally, our results suggest that isobutyric acid is produced by a reversible isomerization of butyric acid, but valeric and caproic acid are not isomerized. These combined insights can inform future efforts to optimize and scale-up the production of valuable chemicals from CO2 using C. luticellarii.

Epigenomic reprogramming of therapy-resistant circulating tumor cells in colon cancer

Therapy resistance is a major challenge in colorectal cancer management. Epigenetic changes, such as DNA methylation, in tumor cells are involved in the development of acquired resistance during treatment. Here, we characterized the DNA methylation landscape of colon circulating tumor cells (CTCs) during cancer progression and therapy resistance development. To this aim, we used nine permanent CTC lines that were derived from peripheral blood samples of a patient with metastatic colon cancer collected before treatment initiation (CTC-MCC-41) and during treatment and cancer progression (CTC-MCC-41.4 and CTC-MCC-41.5 [A-G]). We analyzed the DNA methylome of these nine CTC lines using EPIC arrays and also assessed the association between DNA methylation and gene expression profiles. We confirmed DNA methylation and gene expression results by pyrosequencing and RT-qPCR, respectively. The global DNA methylation profiles were different in the pre-treatment CTC line and in CTC lines derived during therapy resistance development. These resistant CTC lines were characterized by a more hypomethylated profile compared with the pre-treatment CTC line. Most of the observed DNA methylation differences were localized at CpG-poor regions and some in CpG islands, shore regions and promoters. We identified a distinctive DNA methylation signature that clearly differentiated the pre-treatment CTC line from the others. Of note, the genes involved in this signature were associated with cancer-relevant pathways, including PI3K/AKT, MAPK, Wnt signaling and metabolism. We identified several epigenetically deregulated genes associated with therapy resistance in CTCs, such as AP2M1. Our results bring new knowledge on the epigenomic landscape of therapy-resistant CTCs, providing novel mechanisms of resistance as well as potential biomarkers and therapeutic targets for advanced CRC management.

Unraveling the periprandial changes in brain serotonergic activity and its correlation with food intake-related neuropeptides in rainbow trout Oncorhynchus mykiss

This study explored changes in brain serotonin content and activity together with hypothalamic neuropeptide mRNA abundance around feeding time in rainbow trout, as well as the effect of one-day fasting. Groups of trout fed at two (ZT2) and six (ZT6) hours after lights on were sampled from 90 minutes before to 240 minutes after feeding, while additional groups of non-fed trout were also included in the study. Changes in brain amine and metabolite contents were measured in hindbrain, diencephalon and telencephalon, while in the diencephalon the mRNA abundance of tryptophan hydroxylase (tph1, tph2), serotonin receptors (5htr1a, 5htr1b and 5htr2c) and several neuropeptides (npy, agrp1, cartpt, pomca1, crfb) involved in the control of food intake were also assessed. The results showed changes in the hypothalamic neuropeptides that were consistent with the expected role for each in the regulation of food intake in rainbow trout. Serotonergic activity increased rapidly at the time of food intake in the diencephalon and hindbrain and remained high for much of the postprandial period. This increase in serotonin abundance was concomitant with elevated levels of pomca1 mRNA in the diencephalon, suggesting that serotonin might act on brain neuropeptides to promote a satiety profile. Furthermore, serotonin synthesis and neuronal activity appear to increase already before the time of feeding, suggesting additional functions for this amine before and during food intake. Exploration of serotonin receptors in the diencephalon revealed only small changes for gene expression of 5htr1b and 5htr2c receptors during the postprandial phase. Therefore, the results suggest that serotonin may play a relevant role in the regulation of feeding behavior in rainbow trout during periprandial time, but a better understanding of its interaction with brain centers involved in receiving and processing food-related signals is still needed.

An empirical evaluation of the estimation of inbreeding depression from molecular markers under suboptimal conditions

Inbreeding depression (ID), the reduction in fitness due to inbreeding, is typically measured by the regression of the phenotypic values of individuals for a particular trait on their corresponding inbreeding coefficients (F). While genealogical records can provide these coefficients, they may be unavailable or incomplete, making molecular markers a useful alternative. The power to detect ID and its accuracy depend on the variation of F values of individuals, the sample sizes available, and the accuracy in the estimation of individual fitness traits and F values. In this study, we used Drosophila melanogaster to evaluate the effectiveness of molecular markers in estimating ID under suboptimal conditions. We generated two sets of 100 pairs of unrelated individuals from a large panmictic population and mated them for two generations to produce non-inbred and unrelated individuals (F = 0) and inbred individuals (full-sib progeny; F = 0.25). Using these expected genealogical F values, we calculated inbreeding depression for two fitness-related traits, pupae productivity and competitive fitness. We then sequenced the males from 17 non-inbred pairs and 17 inbred pairs to obtain their genomic inbreeding coefficients and estimate ID for the two traits. The scenario assumed was rather restrictive in terms of estimation of ID because: (1) the individuals belonged to the same generation of a large panmictic population, leading to low variation in individual F coefficients; (2) the sample sizes were small; and (3) the traits measured depended on both males and females while only males were sequenced. Despite the challenging conditions of our study, we found that molecular markers provided estimates of ID that were comparable to those obtained from simple pedigree estimations with larger sample sizes. The results therefore suggest that genomic measures of inbreeding are useful to provide estimates of inbreeding depression even under very challenging scenarios.

MoBioTools: A toolkit to setup quantum mechanics/molecular mechanics calculations

We present a toolkit that allows for the preparation of QM/MM input files from a conformational ensemble of molecular geometries. The package is currently compatible with trajectory and topology files in Amber, CHARMM, GROMACS and NAMD formats, and has the possibility to generate QM/MM input files for Gaussian (09 and 16), Orca (≥4.0), NWChem and (Open)Molcas. The toolkit can be used in command line, so that no programming experience is required, although it presents some features that can also be employed as a python application programming interface. We apply the toolkit in four situations in which different electronic-structure properties of organic molecules in the presence of a solvent or a complex biological environment are computed: the reduction potential of the nucleobases in acetonitrile, an energy decomposition analysis of tyrosine interacting with water, the absorption spectrum of an azobenzene derivative integrated into a voltage-gated ion channel, and the absorption and emission spectra of the luciferine/luciferase complex. These examples show that the toolkit can be employed in a manifold of situations for both the electronic ground state and electronically excited states. It also allows for the automatic correction of the active space in the case of CASSCF calculations on an ensemble of geometries, as it is shown for the azobenzene derivative photoswitch case.

Role of Dipolar Interactions on the Determination of the Effective Magnetic Anisotropy in Iron Oxide Nanoparticles

Challenging magnetic hyperthermia (MH) applications of immobilized magnetic nanoparticles require detailed knowledge of the effective anisotropy constant (K_eff ) to maximize heat release. Designing optimal MH experiments entails the precise determination of magnetic properties, which are, however, affected by the unavoidable concurrence of magnetic interactions in common experimental conditions. In this work, a mean-field energy barrier model (ΔE), accounting for anisotropy (E_A ) and magnetic dipolar (E_D ) energy, is proposed and used in combination with AC measurements to a specifically developed model system of spherical magnetic nanoparticles with well-controlled silica shells, acting as a spacer between the magnetic cores. This approach makes it possible to experimentally demonstrate the mean field dipolar interaction energy prediction with the interparticle distance, d_ij , E_D ≈ 1/d_ij ³ and obtain the E_A as the asymptotic limit for very large d_ij . In doing so, K_eff uncoupled from interaction contributions is obtained for the model system (iron oxide cores with average sizes of 8.1, 10.2, and 15.3 nm) revealing to be 48, 23, and 11 kJ m^-3 , respectively, close to bulk magnetite/maghemite values and independent from the specific spacing shell thicknesses selected for the study.

Applying a muscle fatigue model when optimizing load-sharing between muscles for short-duration high-intensity exercise: A preliminary study

Introduction: Multiple different mathematical models have been developed to represent muscle force, to represent multiple muscles in the musculoskeletal system, and to represent muscle fatigue. However, incorporating these different models together to describe the behavior of a high-intensity exercise has not been well described. Methods: In this work, we adapted the three-compartment controller (3CCr) muscle fatigue model to be implemented with an inverse-dynamics based optimization algorithm for the muscle recruitment problem for 7 elbow muscles to model a benchmark case: elbow flexion/extension moments. We highlight the difficulties in achieving an accurate subject-specific approach for this multi-level modeling problem, considering different muscular models, compared with experimental measurements. Both an isometric effort and a dynamic bicep curl were considered, where muscle activity and resting periods were simulated to obtain the fatigue behavior. Muscle parameter correction, scaling and calibration are addressed in this study. Moreover, fiber-type recruitment hierarchy in force generation was added to the optimization problem, thus offering an additional novel muscle modeling criterion. Results: It was observed that: i) the results were most accurate for the static case; ii) insufficient torque was predicted by the model at some time points for the dynamic case, which benefitted from a more precise calibration of muscle parameters; iii) modeling the effects of muscular potentiation may be important; and iv) for this multilevel model approach, the 3CCr model had to be modified to avoid reaching situations of unrealistic constant fatigue in high intensity exercise-resting cycles. Discussion: All the methods yield reasonable estimations, but the complexity of obtaining accurate subject-specific human models is highlighted in this study. The proposed novel muscle modeling and force recruitment criterion, which consider the muscular fiber-type distinction, show interesting preliminary results.

Exogenous application of stress-related signaling molecules affect growth and cannabinoid accumulation in medical cannabis (Cannabis sativa L.)

Medical cannabis (Cannabis sativa L.) is a source of bioactive phytochemicals with promising pharmacological and therapeutic applications. Enhancing the accumulation of valuable bioactive compounds is potentially a way of increasing the economic importance of this crop. Signaling molecules like salicylic acid (SA), jasmonic acid (JA), and γ-aminobutyric acid (GABA) are involved in the regulation of plant development and responses to biotic and abiotic stresses. Moreover, several phytohormones regulate plant trichome formation and elicit the synthesis of secondary metabolites in many plant species in both in vitro and in vivo systems. Therefore, exogenously delivered plant signaling molecules have the potential to modify the chemical profiles of medical cannabis. In this study, we found that the foliar application of SA, methyl jasmonate (MeJA), and GABA produces changes in the accumulation of the two major cannabinoids, cannabidiolic acid (CBDA) and Δ⁹- tetrahydrocannabinolic acid (THCA), in leaves and inflorescences of a medical cannabis variety. MeJA at 0.1 mM increased the CBDA content in inflorescences by 15.6%, while SA and MeJA at 0.1 mM increased CBDA and THCA accumulation in leaves by up to 57.3%. Treatments did not change the expression of genes participating in the final steps of the biosynthetic pathway of cannabinoids: olivetolic acid cyclase (CsOAC-1 and CsOAC-2), 2-acylphloroglucinol 4-prenyltransferase (CsPT4), cannabidiolic acid synthase (CsCBDAS), and tetrahydrocannabinolic acid synthase (CsTHCAS). Trichome density was not significantly different from the control plants in any treatment. Besides, we found strong correlations between several plant growth parameters and cannabinoid yields, showing a direct link between plant fitness and the production of cannabinoids.

Synthesis and Vasorelaxant Activity of Nitrate-Coumarin Derivatives

Due to the need for new chemical entities for cardiovascular diseases, we have synthesized a new series of nitrate-coumarins and evaluated their vasorelaxant activity in contraction-relaxation studies using rat aorta rings precontracted with phenylephrine or by depolarization with a high concentration of potassium chloride. Four of the new compounds were able to relax smooth vascular muscle with a similar profile and potency to glyceryl trinitrate (IC50 =12.73 nM) and sodium nitroprusside (IC50 =4.32 nM). Coumarin-7-yl-methyl nitrate (4), the best compound within the series, was able to relax smooth vascular muscle in the low nanomolar range (IC50 =1.92 nM). The mechanisms of action have been explored, being the activation of sGC and the opening of K+ channels involved. Our studies indicate that the new nitrate derivatives are reversible and not deleterious for aortic rings, suggesting that these compounds have a potential interest for the development of new and highly efficient vasodilator drugs.

A genome-wide cell-free DNA methylation analysis identifies an episignature associated with metastatic luminal B breast cancer

Breast cancers of the luminal B subtype are frequent tumors with high proliferation and poor prognosis. Epigenetic alterations have been found in breast tumors and in biological fluids. We aimed to profile the cell-free DNA (cfDNA) methylome of metastatic luminal B breast cancer (LBBC) patients using an epigenomic approach to discover potential noninvasive biomarkers. Plasma cfDNA was analyzed using the Infinium MethylationEpic array in a cohort of 14 women, including metastatic LBBC patients and nontumor controls. The methylation levels of cfDNA and tissue samples were validated with droplet digital PCR. The methylation and gene expression data of 582 primary luminal breast tumors and 79 nontumor tissues were obtained from The Cancer Genome Atlas (TCGA). We found an episignature of 1,467 differentially methylated CpGs that clearly identified patients with LBBC. Among the genes identified, the promoter hypermethylation of WNT1 was validated in cfDNA, showing an area under the ROC curve (AUC) of 0.86 for the noninvasive detection of metastatic LBBC. Both paired cfDNA and primary/metastatic breast tumor samples showed hypermethylation of WNT1. TCGA analysis revealed significant WNT1 hypermethylation in the primary tumors of luminal breast cancer patients, with a negative association between WNT1 methylation and gene expression. In this proof-of-principle study, we discovered an episignature associated with metastatic LBBC using a genome-wide cfDNA methylation approach. We also identified the promoter hypermethylation of WNT1 in cfDNA as a potential noninvasive biomarker for luminal breast cancer. Our results support the use of EPIC arrays to identify new epigenetic noninvasive biomarkers in breast cancer.

Depletion of ALMS1 affects TGF-β signalling pathway and downstream processes such as cell migration and adhesion capacity

Background: ALMS1 is a ubiquitous gene associated with Alström syndrome (ALMS). The main symptoms of ALMS affect multiple organs and tissues, generating at last, multi-organic fibrosis in the lungs, kidneys and liver. TGF-β is one of the main pathways implicated in fibrosis, controlling the cell cycle, apoptosis, cell migration, cell adhesion and epithelial-mesenchymal transition (EMT). Nevertheless, the role of ALMS1 gene in fibrosis generation and other implicated processes such as cell migration or cell adhesion via the TGF- β pathway has not been elucidated yet. Methods: Initially, we evaluated how depletion of ALMS1 affects different processes like apoptosis, cell cycle and mitochondrial activity in HeLa cells. Then, we performed proteomic profiling with TGF-β stimuli in HeLa ALMS1 -/- cells and validated the results by examining different EMT biomarkers using qPCR. The expression of these EMT biomarkers were also studied in hTERT-BJ-5ta ALMS1 -/-. Finally, we evaluated the SMAD3 and SMAD2 phosphorylation and cell migration capacity in both models. Results: Depletion of ALMS1 generated apoptosis resistance to thapsigargin (THAP) and C2-Ceramide (C2-C), and G2/M cell cycle arrest in HeLa cells. For mitochondrial activity, results did not show significant differences between ALMS1 +/+ and ALMS1 -/-. Proteomic results showed inhibition of downstream pathways regulated by TGF-β. The protein-coding genes (PCG) were associated with processes like focal adhesion or cell-substrate adherens junction in HeLa. SNAI1 showed an opposite pattern to what would be expected when activating the EMT in HeLa and BJ-5ta. Finally, in BJ-5ta model a reduced activation of SMAD3 but not SMAD2 were also observed. In HeLa model no alterations in the canonical TGF-β pathway were observed but both cell lines showed a reduction in migration capacity. Conclusion: ALMS1 has a role in controlling the cell cycle and the apoptosis processes. Moreover, the depletion of ALMS1 affects the signal transduction through the TGF-β and other processes like the cell migration and adhesion capacity.

Endophytic fungi from kale (Brassica oleracea var. acephala) modify roots-glucosinolate profile and promote plant growth in cultivated Brassica species. First description of Pyrenophora gallaeciana

Endophytic fungi of crops can promote plant growth through various mechanisms of action (i.e., improve nutrient uptake and nutrient use efficiency, and produce and modulate plant hormones). The genus Brassica includes important horticultural crops, which have been little studied in their interaction with endophytic fungi. Previously, four endophytic fungi were isolated from kale roots (Brassica oleracea var. acephala), with different benefits for their host, including plant growth promotion, cold tolerance, and induction of resistance to pathogens (Xanthomonas campestris) and pests (Mamestra brassicae). In the present work, the molecular and morphological identification of the four different isolates were carried out, describing them as the species Acrocalymma vagum, Setophoma terrestris, Fusarium oxysporum, and the new species Pyrenophora gallaeciana. In addition, using a representative crop of each Brassica U’s triangle species and various in vitro biochemical tests, the ability of these fungi to promote plant growth was described. In this sense, the four fungi used promoted the growth of B. rapa, B. napus, B. nigra, B. juncea, and B. carinata, possibly due to the production of auxins, siderophores, P solubilization or cellulase, xylanase or amylase activity. Finally, the differences in root colonization between the four endophytic fungi and two pathogens (Leptosphaeria maculans and Sclerotinia sclerotiorum) and the root glucosinolate profile were studied, at different times. In this way, how the presence of progoitrin in the roots reduces their colonization by endophytic and pathogenic fungi was determined, while the possible hydrolysis of sinigrin to fungicidal products controls the colonization of endophytic fungi, but not of pathogens.

Trip13 Depletion in Liver Cancer Induces a Lipogenic Response Contributing to Plin2-Dependent Mitotic Cell Death

Aberrant energy metabolism and cell cycle regulation both critically contribute to malignant cell growth and both processes represent targets for anticancer therapy. It is shown here that depletion of the AAA+-ATPase thyroid hormone receptor interacting protein 13 (Trip13) results in mitotic cell death through a combined mechanism linking lipid metabolism to aberrant mitosis. Diminished Trip13 levels in hepatocellular carcinoma cells result in insulin-receptor-/Akt-pathway-dependent accumulation of lipid droplets, which act as functional acentriolar microtubule organizing centers disturbing mitotic spindle polarity. Specifically, the lipid-droplet-coating protein perilipin 2 (Plin2) is required for multipolar spindle formation, induction of DNA damage, and mitotic cell death. Plin2 expression in different tumor cells confers susceptibility to cell death induced by Trip13 depletion as well as treatment with paclitaxel, a spindle-interfering drug commonly used against different cancers. Thus, assessment of Plin2 levels enables the stratification of tumor responsiveness to mitosis-targeting drugs, including clinically approved paclitaxel and Trip13 inhibitors currently under development.

In vitro inhibition of starch digestive enzymes by ultrasound-assisted extracted polyphenols from Ascophyllum nodosum seaweeds

Seaweeds are gaining importance due to their antidiabetic characteristics. This study investigated the inhibitory effects of aqueous Ascophyllum nodosum extracts, obtained by ultrasound-assisted extraction with different sonication powers (70-90 W/cm2 ) and subjected to resin purification, against α-amylase and α-glucosidase enzymes. Different inhibition methodologies were carried out, preincubating the extract either with the enzyme or the substrate. Chemical characterization, in terms of proximate analysis, antioxidant capacity (2,2-diphenyl-1-picryl-hydrazyl-hydrate [DPPH] and FRAP), and polyphenols characteristics (reversed-phase high-performance liquid chromatography [RP-HPLC] and 1 H-NMR) were carried out to explain inhibitory activities of extracts. Sonication power did not influence the proximal composition nor antiradical activity of extracts, but increasing sonication power increased inhibition capacity (>15%) against both starch digestive enzymes. The extract purification largely improved the inhibition efficiency decreasing the IC50 of α-amylase and α-glucosidase by 3.0 and 6.1 times, respectively. Seaweed extracts showed greater inhibition effect when they were preincubated with the enzyme instead of the substrate. RP-HPLC together with 1 H-NMR spectra allowed relating the presence of uronic acids-polyphenols complexes and quinones in the extracts with the different inhibitory capacities of samples. PRACTICAL APPLICATION: The study confirms that ultrasound-assisted extracts from Ascophyllum nodosum can be used to inhibit digestive enzymes. This opens the alternative to be used in foods for modulating glycemic index.

Origin makes a difference: Alternative responses of an AM-dependent plant to mycorrhizal inoculum from invaded and native soils under abiotic stress

The presence of invasive alien plants (IAPs) alters the composition of soil arbuscular mycorrhizal (AM) fungal communities. Although fundamental for plant development, plant responses to AM from invaded soils have not been widely explored, especially under environmental stress. We compared plant growth, P accumulation, root colonization and the photosynthetic responses of the native AM-dependent Plantago lanceolata growing in contact with AM fungi from communities invaded by Acacia dealbata Link (AMinv) or non-invaded communities (AMnat) exposed to water and light restriction (shade). Under optimal growing conditions, plants in contact with AMnat produced higher leaf biomass and accumulated more P. However, plant responses to different AM inocula varied as the level of stress increased. Inoculation with AMinv promoted plant growth and root length under light restriction. When plants grew in contact with AMnat under drought, leaf P increased under severe water restriction, and leaf and root P increased under intermediate water irrigation. Growing in contact with the AMnat inoculum promoted root P content in both full light and light restriction. Colonization rates of P. lanceolata roots were comparable between treatments, and plants maintained photosynthetic activity within similar ranges, regardless of the level of stress applied. Our results suggest that origin of the inoculum (native soils versus invaded soils) did not affect the ability of AM species therein to establish effective mutualistic associations with P. lanceolata roots but did influence plant responses depending on the type and level of the abiotic stress.

Visualization and identification of single meteoritic organic molecules by atomic force microscopy

Using high-resolution atomic force microscopy (AFM) with CO-functionalized tips, we atomically resolved individual molecules from Murchison meteorite samples. We analyzed powdered Murchison meteorite material directly, as well as processed extracts that we prepared to facilitate characterization by AFM. From the untreated Murchison sample, we resolved very few molecules, as the sample contained mostly small molecules that could not be identified by AFM. By contrast, using a procedure based on several trituration and extraction steps with organic solvents, we isolated a fraction enriched in larger organic compounds. The treatment increased the fraction of molecules that could be resolved by AFM, allowing us to identify organic constituents and molecular moieties, such as polycyclic aromatic hydrocarbons and aliphatic chains. The AFM measurements are complemented by high-resolution mass spectrometry analysis of Murchison fractions. We provide a proof of principle that AFM can be used to image and identify individual organic molecules from meteorites and propose a method for extracting and preparing meteorite samples for their investigation by AFM. We discuss the challenges and prospects of this approach to study extraterrestrial samples based on single-molecule identification.

Semaphorin3B plays a central role in serum-induced arthritis model and is reduced in patients with rheumatoid arthritis

Objective

Semaphorin 3B (Sema3B) decreases the migratory and invasive capacities of fibroblast‐like synoviocytes (FLS) in rheumatoid arthritis (RA) and suppresses expression of matrix metalloproteinases. We undertook this study to examine the role of Sema3B in a mouse model of arthritis and its expression in RA patients.

Methods

Clinical responses, histologic features, and FLS function were examined in wild‐type (WT) and Sema3B^−/− mice in a K/BxN serum transfer model of arthritis. Protein and messenger RNA expression of Sema3B in mouse joints and murine FLS, as well as in serum and synovial tissue from patients with arthralgia and patients with RA, was determined using enzyme‐linked immunosorbent assay, immunoblotting, quantitative polymerase chain reaction, and RNA sequencing. FLS migration was determined using a wound closure assay.

Results

The clinical severity of serum‐induced arthritis was significantly higher in Sema3B^−/− mice compared to WT mice. This was associated with increased expression of inflammatory mediators and increased migratory capacity of murine FLS. Administration of recombinant mouse Sema3B reduced the clinical severity of serum‐induced arthritis and the expression of inflammatory mediators. Sema3B expression was significantly lower in the synovial tissue and serum of patients with established RA compared to patients with arthralgia. Serum Sema3B levels were elevated in patients with arthralgia that later progressed to RA, but not in those who did not develop RA; however, these levels drastically decreased 1 and 2 years after RA development.

Conclusion

Sema3B expression plays a protective role in a mouse model of arthritis. In RA patients, expression levels of Sema3B in the serum depend on the disease stage, suggesting different regulatory roles in disease onset and progression.

Defect Passivation in Lead-Halide Perovskite Nanocrystals and Thin Films: Toward Efficient LEDs and Solar Cells

Lead-halide perovskites (LHPs), in the form of both colloidal nanocrystals (NCs) and thin films, have emerged over the past decade as leading candidates for next-generation, efficient light-emitting diodes (LEDs) and solar cells. Owing to their high photoluminescence quantum yields (PLQYs), LHPs efficiently convert injected charge carriers into light and vice versa. However, despite the defect-tolerance of LHPs, defects at the surface of colloidal NCs and grain boundaries in thin films play a critical role in charge-carrier transport and nonradiative recombination, which lowers the PLQYs, device efficiency, and stability. Therefore, understanding the defects that play a key role in limiting performance, and developing effective passivation routes are critical for achieving advances in performance. This Review presents the current understanding of defects in halide perovskites and their influence on the optical and charge-carrier transport properties. Passivation strategies toward improving the efficiencies of perovskite-based LEDs and solar cells are also discussed.

Analysis of Endogenous Peptides Released from Osteoarthritic Cartilage Unravels Novel Pathogenic Markers

Osteoarthritis (OA) is a pathology characterized by the loss of articular cartilage. In this study, we performed a peptidomic strategy to identify endogenous peptides (neopeptides) that are released from human osteoarthritic tissue, which may serve as disease markers. With this aim, secretomes of osteoarthritic and healthy articular cartilages obtained from knee and hip were analyzed by shotgun peptidomics. This discovery step led to the identification of 1175 different peptides, corresponding to 101 proteins, as products of the physiological or pathological turnover of cartilage extracellular matrix. Then, a targeted multiple reaction monitoring-mass spectrometry method was developed to quantify the panel of best marker candidates on a larger set of samples (n = 62). Statistical analyses were performed to evaluate the significance of the observed differences and the ability of the neopeptides to classify the tissue. Eight of them were differentially abundant in the media from wounded zones of OA cartilage compared with the healthy tissue (p < 0.05). Three neopeptides belonging to Clusterin and one from Cartilage Oligomeric Matrix Protein showed a disease-dependent decrease specifically in hip OA, whereas two from Prolargin (PRELP) and one from Cartilage Intermediate Layer Protein 1 were significantly increased in samples from knee OA. The release of one peptide from PRELP showed the best metrics for tissue classification (AUC = 0.834). The present study reveals specific neopeptides that are differentially released from knee or hip human osteoarthritic cartilage compared with healthy tissue. This evidences the intervention of characteristic pathogenic pathways in OA and provides a novel panel of peptidic candidates for biomarker development.