Effect of Melatonin on Chemoresistance Exhibited by Spheres Derived from Canine Mammary Carcinoma Cells

Mammary cancer is a frequent disease in female dogs, where a high proportion of cases correspond to malignant tumors that may exhibit drug resistance. Within the mammary tumor microenvironment, there is a cell subpopulation called cancer stem cells (CSCs), which are capable of forming spheres in vitro and resisting anti-tumor treatments, partly explaining the recurrence of some tumors. Previously, it has been described that spheres derived from canine mammary carcinoma cells CF41.Mg and REM 134 exhibit stemness characteristics. Melatonin has shown anti-tumor effects on mammary tumor cells; however, its effects have been poorly evaluated in canine mammary CSCs. This study aimed to analyze the effect of melatonin on the chemoresistance exhibited by stem-like neoplastic cells derived from canine mammary carcinoma to cytotoxic drugs such as doxorubicin and mitoxantrone. CF41.Mg and REM 134 cells were cultured in high-glucose DMEM supplemented with fetal bovine serum and L-glutamine. The spheres were cultured in ultra-low attachment plates in DMEM/F12 medium without fetal bovine serum and with different growth factors. The CD44+/CD24-/low phenotype was analyzed by flow cytometry. The viability of sphere-derived cells (MTS reduction) was studied in the presence of melatonin (0.1 or 1 mM), doxorubicin, mitoxantrone, and luzindole. In addition, the gene (RT-qPCR) of the multidrug resistance bombs MDR1 and ABCG2 were analyzed in the presence of melatonin. Both cell types expressed the MT1 gene, which encodes the melatonin receptor MT1. Melatonin 1 mM does not modify the CD44+/CD24-/low phenotype; however, the hormone reduced viability (p < 0.0001) only in CF41.Mg spheres, without inducing an additive effect when co-incubated with cytotoxic drugs. These effects were independent of the binding of the hormone to its receptor MT1, since, by pharmacologically inhibiting them, the effect of melatonin was not blocked. In CF41.Mg spheres, the relative gene expression of ABCG2 and MDR1 was decreased in response to the hormone (p < 0.001). These results indicate that melatonin negatively modulates the cell survival of spheres derived from CF41.Mg cells, in a way that is independent of its MT1 receptor. These effects did not counteract the resistance to doxorubicin and mitoxantrone, even though the hormone negatively regulates the gene expression of MDR1 and ABCG2.

In Situ Accumulation of CaOx Crystals in C. quitensis Leaves and Its Relationship with Anatomy and Gas Exchange

The accumulation of crystal calcium oxalate (CaOx) in plants is linked to a type of stress-induced photosynthesis termed 'alarm photosynthesis', serving as a carbon reservoir when carbon dioxide (CO2) exchange is constrained. Colobanthus quitensis is an extremophyte found from southern Mexico to Antarctica, which thrives in high-altitude Andean regions. Growing under common garden conditions, C. quitensis from different latitudinal provenances display significant variations in CaOx crystal accumulation. This raises the following questions: are these differences maintained under natural conditions? And is the CaOx accumulation related to mesophyll conductance (gm) and net photosynthesis (AN) performed in situ? It is hypothesized that in provenances with lower gm, C. quitensis will exhibit an increase in the use of CaOx crystals, resulting in reduced crystal leaf abundance. Plants from Central Chile (33°), Patagonia (51°), and Antarctica (62°) were measured in situ and sampled to determine gas exchange and CaOx crystal accumulation, respectively. Both AN and gm decrease towards higher latitudes, correlating with increases in leaf mass area and leaf density. The crystal accumulation decreases at higher latitudes, correlating positively with AN and gm. Thus, in provenances where environmental conditions induce more xeric traits, the CO2 availability for photosynthesis decreases, making the activation of alarm photosynthesis feasible as an internal source of CO2.

Activated carbon from avocado seed as sorbent phase for microextraction technologies: activation, characterization, and analytical performance

According to green analytical chemistry principles, the use of agricultural byproducts as sorbent phases is an interesting topic due to their lignocellulosic origin, as they are biodegradable and inexpensive. To the best of our knowledge, this is the first study in which avocado seed and avocado seed activated carbon are proposed as sustainable sorbents for solid-phase microextraction technologies, which were used to assess the proof of concept. Rotating disk sorptive extraction (RDSE) was used as a model technology and ibuprofen (Ibu) and 1-hydroxy-ibuprofen (1-OH-Ibu) as representative analytes. It was found that activated carbon (AC) prepared at 600 °C with an impregnation ratio (raw material/activating agent (ZnCl2), w/w) of 1:1.2 had better extraction efficiency than other ACs obtained at different temperatures, impregnation ratios, and activating agents (K2CO3). Characterization revealed several differences between natural avocado seed, biochar prepared at 600 °C, and selected AC since the typical functional groups of the natural starting material begin to disappear with pyrolysis and increasing the surface area and pore volume, suggesting that the main interactions between analytes and the sorbent material are pore filling and π-π stacking. By using this AC as the sorbent phase, the optimal extraction conditions in RDSE were as follows: the use of 50 mg of sorbent in the disk, 30 mL of sample volume, pH 4, 90 min of extraction time at a rotation velocity of the disk of 2000 rpm, and methanol as the elution solvent. The extracts were analyzed via gas chromatography coupled to mass spectrometry (GC-MS). The method provided limits of detection of 0.23 and 0.07 µg L-1 and recoveries of 81% and 91% for Ibu and 1-OH-Ibu, respectively. When comparing the extraction efficiency of the selected activated carbon with those provided by Oasis® HLB and C18 in RDSE, nonsignificant differences were observed, indicating that avocado seed activated carbon is a suitable alternative to these commercial materials.

Ecophysiology of Antarctic Vascular Plants: An Update on the Extreme Environment Resistance Mechanisms and Their Importance in Facing Climate Change

Antarctic flowering plants have become enigmatic because of their unique capability to colonize Antarctica. It has been shown that there is not a single trait that makes Colobanthus quitensis and Deschampsia antarctica so special, but rather a set of morphophysiological traits that coordinately confer resistance to one of the harshest environments on the Earth. However, both their capacity to inhabit Antarctica and their uniqueness remain not fully explained from a biological point of view. These aspects have become more relevant due to the climatic changes already impacting Antarctica. This review aims to compile and update the recent advances in the ecophysiology of Antarctic vascular plants, deepen understanding of the mechanisms behind their notable resistance to abiotic stresses, and contribute to understanding their potential responses to environmental changes. The uniqueness of Antarctic plants has prompted research that emphasizes the role of leaf anatomical traits and cell wall properties in controlling water loss and CO2 exchange, the role of Rubisco kinetics traits in facilitating efficient carbon assimilation, and the relevance of metabolomic pathways in elucidating key processes such as gas exchange, nutrient uptake, and photoprotection. Climate change is anticipated to have significant and contrasting effects on the morphophysiological processes of Antarctic species. However, more studies in different locations outside Antarctica and using the latitudinal gradient as a natural laboratory to predict the effects of climate change are needed. Finally, we raise several questions that should be addressed, both to unravel the uniqueness of Antarctic vascular species and to understand their potential responses to climate change.

Usefulness of Peripheral Blood Cultures in Children With Cancer and Episodes of Fever and Neutropenia

BACKGROUND

The collection of blood cultures (BC) is key for guiding antimicrobial therapy in children with febrile neutropenia (FN), more than 90% have central venous catheters (CVC). There is no consensus on the need for peripheral BC over central BC in this population. The aim of this study was to determine the contribution of peripheral BC over central BC in the diagnosis of bloodstream infections in children with FN.

METHODS

Descriptive, retrospective study, episodes of FN recorded prospectively in 6 hospitals in Santiago, Chile, from 2016 to 2021. Central and peripheral BC were drawn upon admission. All episodes with at least one (+) BC were allocated to one of these groups: consistent (+) BC, inconsistent (+) BC, only CVC (+) BC and only peripheral (+) BC. The volume of the samples was recorded.

RESULTS

The analysis included 241 episodes of FN with at least one (+) BC. The median age was 7.2 years, 51% were female, 84% had hematological cancer and 98% had episodes of high-risk FN. Of a total of 241 episodes, 135 (56%) had consistent (+) BC, 13 (5%) had inconsistent (+) BC, 35 (15%) had only CVC (+) BC and 58 (24%) had only peripheral (+) BC. There were no significant differences in the volume of the samples between central and peripheral BC.

CONCLUSIONS

The proportion of bloodstream infections detected only through peripheral BC was 24%, higher than previously reported, not due to sample volume. We recommend obtaining peripheral as well CVC BC in children with FN.

Novel Apoplastic Antifreeze Proteins of Deschampsia antarctica as Enhancer of Common Cell Freezing Media for Cryobanking of Genetic Resources, a Preliminary Study

Antifreeze proteins (AFPs) are natural biomolecules found in cold-adapted organisms that lower the freezing point of water, allowing survival in icy conditions. These proteins have the potential to improve cryopreservation techniques by enhancing the quality of genetic material postthaw. Deschampsia antarctica, a freezing-tolerant plant, possesses AFPs and is a promising candidate for cryopreservation applications. In this study, we investigated the cryoprotective properties of AFPs from D. antarctica extracts on Atlantic salmon spermatozoa. Apoplastic extracts were used to determine ice recrystallization inhibition (IRI), thermal hysteresis (TH) activities and ice crystal morphology. Spermatozoa were cryopreserved using a standard cryoprotectant medium (C+) and three alternative media supplemented with apoplastic extracts. Flow cytometry was employed to measure plasma membrane integrity (PMI) and mitochondrial membrane potential (MMP) postthaw. Results showed that a low concentration of AFPs (0.05 mg/mL) provided significant IRI activity. Apoplastic extracts from D. antarctica demonstrated a cryoprotective effect on salmon spermatozoa, with PMI comparable to the standard medium. Moreover, samples treated with apoplastic extracts exhibited a higher percentage of cells with high MMP. These findings represent the first and preliminary report that suggests that AFPs derived from apoplastic extracts of D. antarctica have the potential to serve as cryoprotectants and could allow the development of novel freezing media.

Behavioral and electrophysiological evidence of different processes during a target identification task assessing perceptual learning

This study aimed to test whether a target identification task involving same and different judgments to assess the ability to differentiate between similar pre-exposed stimuli-i.e., perceptual learning-could actually be assessing two different cognitive processes. Specifically, the hypothesis was that while "different" trials might be truly assessing the ability to differentiate between the pre-exposed stimuli, "same" trials might be assessing the ability to recognize one of these stimuli as the target. To test this hypothesis, accuracy on judgments as well as reaction times and event-related potentials for same/different trials were recorded after concurrent pre-exposure to similar stimuli. If same/different trials were assessing cognitive processes with different time courses, distinct outcomes for such trials would be expected at the behavioral and neural level. Results showed that participants were very accurate both in same and different judgments, indicating that they were perfectly able to differentiate between the stimuli after their concurrent presentations. However, larger P3 latencies and slower reaction times for different trials than for same trials were found. These results seem to support the idea that cognitive processes activated in same and different trials are different due to their distinct time courses. The importance of these findings for the theoretical approaches to perceptual learning is discussed.

Lactadherin immunoblockade in small extracellular vesicles inhibits sEV-mediated increase of pro-metastatic capacities

BACKGROUND

Tumor-derived small extracellular vesicles (sEVs) can promote tumorigenic and metastatic capacities in less aggressive recipient cells mainly through the biomolecules in their cargo. However, despite recent advances, the specific molecules orchestrating these changes are not completely defined. Lactadherin is a secreted glycoprotein typically found in the milk fat globule membrane. Its overexpression has been associated with increased tumorigenesis and metastasis in breast cancer (BC) and other tumors. However, neither its presence in sEVs secreted by BC cells, nor its role in sEV-mediated intercellular communication have been described. The present study focused on the role of lactadherin-containing sEVs from metastatic MDA-MB-231 triple-negative BC (TNBC) cells (sEV-MDA231) in the promotion of pro-metastatic capacities in non-tumorigenic and non-metastatic recipient cells in vitro, as well as their pro-metastatic role in a murine model of peritoneal carcinomatosis.

RESULTS

We show that lactadherin is present in sEVs secreted by BC cells and it is higher in sEV-MDA231 compared with the other BC cell-secreted sEVs measured through ELISA. Incubation of non-metastatic recipient cells with sEV-MDA231 increases their migration and, to some extent, their tumoroid formation capacity but not their anchorage-independent growth. Remarkably, lactadherin blockade in sEV-MDA231 results in a significant decrease of those sEV-mediated changes in vitro. Similarly, intraperitoneally treatment of mice with MDA-MB-231 BC cells and sEV-MDA231 greatly increase the formation of malignant ascites and tumor micronodules, effects that were significantly inhibited when lactadherin was previously blocked in those sEV-MDA231.

CONCLUSIONS

As to our knowledge, our study provides the first evidence on the role of lactadherin in metastatic BC cell-secreted sEVs as promoter of: (i) metastatic capacities in less aggressive recipient cells, and ii) the formation of malignant ascites and metastatic tumor nodules. These results increase our understanding on the role of lactadherin in sEVs as promoter of metastatic capacities which can be used as a therapeutic option for BC and other malignancies.

A novel pectin methylesterase inhibitor, PMEI3, in common bean suggests a key role of pectin methylesterification in Pseudomonas resistance

The mechanisms underlying susceptibility to and defense against Pseudomonas syringae (Pph) of the common bean (Phaseolus vulgaris) have not yet been clarified. To investigate these, 15-day-old plants of the variety Riñón were infected with Pph and the transcriptomic changes at 2 h and 9 h post-infection were analysed. RNA-seq analysis showed an up-regulation of genes involved in defense/signaling at 2 h, most of them being down-regulated at 9 h, suggesting that Pph inhibits the transcriptomic reprogramming of the plant. This trend was also observed in the modulation of 101 cell wall-related genes. Cell wall composition changes at early stages of Pph infection were associated with homogalacturonan methylation and the formation of egg boxes. Among the cell wall genes modulated, a pectin methylesterase inhibitor 3 (PvPMEI3) gene, closely related to AtPMEI3, was detected. PvPMEI3 protein was located in the apoplast and its pectin methylesterase inhibitory activity was demonstrated. PvPMEI3 seems to be a good candidate to play a key role in Pph infection, which was supported by analysis of an Arabidopsis pmei3 mutant, which showed susceptibility to Pph, in contrast to resistant Arabidopsis Col-0 plants. These results indicate a key role of the degree of pectin methylesterification in host resistance to Pph during the first steps of the attack.

Ultra-High-Resolution Liquid Chromatography Coupled with Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry Analysis of Tessaria absinthioides (Hook. & Arn.) DC. (Asteraceae) and Antioxidant and Hypocholesterolemic Properties

Recently, we reported the chemical profile and the hypocholesterolemic effects of a decoction of Tessaria absinthioides (Hook. & Arn.) DC. (Asteraceae). In this study, we evaluated a methanolic extract (METa) instead. Metabolite profiling was conducted using ultra-high-resolution liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (UHPLC-ESI-QTOF-MS), identifying thirty compounds, including flavonoids, phenolic acids, fatty acids, and phorbolesters. Antioxidant properties were assessed through 2,2-diphenyl-1-picrylhydrazyl (DPPH), Trolox equivalent antioxidant activity (TEAC), ferric-reducing antioxidant power (FRAP), and inhibition of lipid peroxidation in erythrocytes (ILP) assays, exhibiting robust antioxidant activity. The in vivo impact of METa on serum lipid parameters and liver X receptors (LXRs) was evaluated in a hypercholesterolemic animal model. After 14 days on a high-fat diet, male rats received either a vehicle (V) or METa100, METa200 or METa500 (100; 200 and 500 mg METa/kg animal, respectively) for an additional two weeks. METa500 reduced total cholesterol levels (17.62%; p < 0.05) and all doses increased high-density lipoprotein cholesterol levels (METa100: 86.27%; METa200: 48.37%, and METa500: 29.42%; p < 0.0001). However, METa did not alter LXRs expression. The observed antioxidant and hypocholesterolemic properties of METa may be linked to the presence of six di-caffeoylquinic acids. These findings underscore T. absinthioides as a potential candidate for the treatment of metabolic disease.

Cd2+ Sorption Alterations in Ultisol Soils Triggered by Different Engineered Nanoparticles and Incubation Times

The progressive influx of engineered nanoparticles (ENPs) into the soil matrix catalyses a fundamental transformation in the equilibrium dynamics between the soil and the edaphic solution. This all-encompassing investigation is geared towards unravelling the implications of an array of ENP types, diverse dosages and varying incubation durations on the kinetics governing Cd2+ sorption within Ultisol soils. These soils have been subjected to detailed characterizations probing their textural and physicochemical attributes in conjunction with an exhaustive exploration of ENP composition, structure and morphology. To decipher the intricate nuances of kinetics, discrete segments of Ultisol soils were subjected to isolated systems involving ENP dosages of 20 and 500 mg ENPs·kg-1 (AgNPs, CuNPs and FeNPs) across intervals of 1, 3 and 6 months. The comprehensive kinetic parameters were unveiled by applying the pseudo-first-order and pseudo-second-order models. At the same time, the underlying sorption mechanisms were studied via the intra-particle diffusion model. This study underscores the substantial impact of this substrate on the kinetic behaviours of contaminants such as Cd, emphasizing the need for its consideration in soil-linked economic activities and regulatory frameworks to optimize resource management.

Isolation and Identification of Bacteria from Three Geothermal Sites of the Atacama Desert and Their Plant-Beneficial Characteristics

The Region of Arica and Parinacota (Atacama Desert) offers several unexplored remote sites with unique characteristics that would allow for the formulation of new bioproducts for agriculture. Among them, Jurasi Hot Springs, Polloquere Hot Springs, and Amuyo Lagoons represent a group of open pools fed by thermal water springing from the mountains. Their microbiomes remain unspecified, providing a unique opportunity to characterize the endemic community of these sites and develop new bioproducts for sustainable agriculture. Bacteria were isolated from the sediments of these geothermal sites and characterized by sequencing the 16S rRNA gene, microbiological characterization, and agricultural functional characterization. A total of 57 bacteria were isolated from three geothermal sites north of the Atacama Desert. The sequence analysis showed that the isolates belong to several bacterial genera, including Pantoea, Bacillus, and Pseudomonas, among others. The functional characterization revealed the presence of PGP traits, hydrolytic enzymes, and biocontrol activity against phytopathogenic fungi. These bacteria possess the potential to develop new biobased products for agriculture in arid conditions.

Genotype Prevalence of Lactose Deficiency, Vitamin D Deficiency, and the Vitamin D Receptor in a Chilean Inflammatory Bowel Disease Cohort: Insights from an Observational Study

Lactose intolerance (LI) and vitamin D deficiency (VDD) have been linked to inflammatory bowel disease (IBD). We conducted an observational study in 192 Chilean IBD patients to investigate the prevalence of a specific gene variant (LCT-13910 CC genotype) associated with LI and the prevalence of VDD/Vitamin D Receptor (VDR) gene variants. Blood samples were analyzed using Illumina's Infinium Global Screening Array. The LCT-13910 CC genotype was found in 61% of IBD patients, similar to Chilean Hispanic controls and lower than Chilean Amerindian controls. The frequency of the LCT-13910-C allele in Chilean IBD patients (0.79) was comparable to the general population and higher than Europeans (0.49). Regarding VDR and VDD variants, in our study, the rs12785878-GG variant was associated with an increased risk of IBD (OR = 2.64, CI = 1.61-4.32; p-value = 0.001). Sixty-one percent of the Chilean IBD cohort have a genetic predisposition to lactose malabsorption, and a significant proportion exhibit genetic variants associated with VDD/VDR. Screening for LI and VDD is crucial in this Latin American IBD population.

Automated detection of cardiac rest period for trigger delay calculation for image-based navigator coronary magnetic resonance angiography

BACKGROUND

Coronary magnetic resonance angiography (coronary MRA) is increasingly being considered as a clinically viable method to investigate coronary artery disease (CAD). Accurate determination of the trigger delay to place the acquisition window within the quiescent part of the cardiac cycle is critical for coronary MRA in order to reduce cardiac motion. This is currently reliant on operator-led decision making, which can negatively affect consistency of scan acquisition. Recently developed deep learning (DL) derived software may overcome these issues by automation of cardiac rest period detection.

METHODS

Thirty individuals (female, n = 10) were investigated using a 0.9 mm isotropic image-navigator (iNAV)-based motion-corrected coronary MRA sequence. Each individual was scanned three times utilising different strategies for determination of the optimal trigger delay: (1) the DL software, (2) an experienced operator decision, and (3) a previously utilised formula for determining the trigger delay. Methodologies were compared using custom-made analysis software to assess visible coronary vessel length and coronary vessel sharpness for the entire vessel length and the first 4 cm of each vessel.

RESULTS

There was no difference in image quality between any of the methodologies for determination of the optimal trigger delay, as assessed by visible coronary vessel length, coronary vessel sharpness for each entire vessel and vessel sharpness for the first 4 cm of the left mainstem, left anterior descending or right coronary arteries. However, vessel length of the left circumflex was slightly greater using the formula method. The time taken to calculate the trigger delay was significantly lower for the DL-method as compared to the operator-led approach (106 ± 38.0 s vs 168 ± 39.2 s, p < 0.01, 95% CI of difference 25.5-98.1 s).

CONCLUSIONS

Deep learning-derived automated software can effectively and efficiently determine the optimal trigger delay for acquisition of coronary MRA and thus may simplify workflow and improve reproducibility.

Design of β-Keto Esters with Antibacterial Activity: Synthesis, In Vitro Evaluation, and Theoretical Assessment of Their Reactivity and Quorum-Sensing Inhibition Capacity

This work proposes the design of β-keto esters as antibacterial compounds. The design was based on the structure of the autoinducer of bacterial quorum sensing, N-(3-oxo-hexanoyl)-l-homoserine lactone (3-oxo-C6-HSL). Eight β-keto ester analogues were synthesised with good yields and were spectroscopically characterised, showing that the compounds were only present in their β-keto ester tautomer form. We carried out a computational analysis of the reactivity and ADME (absorption, distribution, metabolism, and excretion) properties of the compounds as well as molecular docking and molecular dynamics calculations with the LasR and LuxS quorum-sensing (QS) proteins, which are involved in bacterial resistance to antibiotics. The results show that all the compounds exhibit reliable ADME properties and that only compound 7 can present electrophile toxicity. The theoretical reactivity study shows that compounds 6 and 8 present a differential local reactivity regarding the rest of the series. Compound 8 presents the most promising potential in terms of its ability to interact with the LasR and LuxS QS proteins efficiently according to its molecular docking and molecular dynamics calculations. An initial in vitro antimicrobial screening was performed against the human pathogenic bacteria Pseudomonas aeruginosa and Staphylococcus aureus as well as the phytopathogenic bacteria Pseudomonas syringae and Agrobacterium tumefaciens. Compounds 6 and 8 exhibit the most promising results in the in vitro antimicrobial screening against the panel of bacteria studied.

Liver PDFF estimation using a multi-decoder water-fat separation neural network with a reduced number of echoes

OBJECTIVE

To accurately estimate liver PDFF from chemical shift-encoded (CSE) MRI using a deep learning (DL)-based Multi-Decoder Water-Fat separation Network (MDWF-Net), that operates over complex-valued CSE-MR images with only 3 echoes.

METHODS

The proposed MDWF-Net and a U-Net model were independently trained using the first 3 echoes of MRI data from 134 subjects, acquired with conventional 6-echoes abdomen protocol at 1.5 T. Resulting models were then evaluated using unseen CSE-MR images obtained from 14 subjects that were acquired with a 3-echoes CSE-MR pulse sequence with a shorter duration compared to the standard protocol. Resulting PDFF maps were qualitatively assessed by two radiologists, and quantitatively assessed at two corresponding liver ROIs, using Bland Altman and regression analysis for mean values, and ANOVA testing for standard deviation (STD) (significance level: .05). A 6-echo graph cut was considered ground truth.

RESULTS

Assessment of radiologists demonstrated that, unlike U-Net, MDWF-Net had a similar quality to the ground truth, despite it considered half of the information. Regarding PDFF mean values at ROIs, MDWF-Net showed a better agreement with ground truth (regression slope = 0.94, R2 = 0.97) than U-Net (regression slope = 0.86, R2 = 0.93). Moreover, ANOVA post hoc analysis of STDs showed a statistical difference between graph cuts and U-Net (p < .05), unlike MDWF-Net (p = .53).

CONCLUSION

MDWF-Net showed a liver PDFF accuracy comparable to the reference graph cut method, using only 3 echoes and thus allowing a reduction in the acquisition times.

CLINICAL RELEVANCE STATEMENT

We have prospectively validated that the use of a multi-decoder convolutional neural network to estimate liver proton density fat fraction allows a significant reduction in MR scan time by reducing the number of echoes required by 50%.

KEY POINTS

• Novel water-fat separation neural network allows for liver PDFF estimation by using multi-echo MR images with a reduced number of echoes. • Prospective single-center validation demonstrated that echo reduction leads to a significant shortening of the scan time, compared to standard 6-echo acquisition. • Qualitative and quantitative performance of the proposed method showed no significant differences in PDFF estimation with respect to the reference technique.

EV-miRNA-Mediated Intercellular Communication in the Breast Tumor Microenvironment

Cancer research has prioritized the study of the tumor microenvironment (TME) as a crucial area of investigation. Understanding the communication between tumor cells and the various cell types within the TME has become a focal point. Bidirectional communication processes between these cells support cellular transformation, as well as the survival, invasion, and metastatic dissemination of tumor cells. Extracellular vesicles are lipid bilayer structures secreted by cells that emerge as important mediators of this cell-to-cell communication. EVs transfer their molecular cargo, including proteins and nucleic acids, and particularly microRNAs, which play critical roles in intercellular communication. Tumor-derived EVs, for example, can promote angiogenesis and enhance endothelial permeability by delivering specific miRNAs. Moreover, adipocytes, a significant component of the breast stroma, exhibit high EV secretory activity, which can then modulate metabolic processes, promoting the growth, proliferation, and migration of tumor cells. Comprehensive studies investigating the involvement of EVs and their miRNA cargo in the TME, as well as their underlying mechanisms driving tumoral capacities, are necessary for a deeper understanding of these complex interactions. Such knowledge holds promise for the development of novel diagnostic and therapeutic strategies in cancer treatment.

Heritability of Immunity Traits and Resistance of Atlantic Salmon against the Sea Louse Caligus rogercresseyi

The immune response of Atlantic salmon to sea lice has been extensively studied, but we still do not know the mechanisms by which some fish become resistant and others do not. In this study, we estimated the heritabilities of three key proteins associated with the innate immunity and resistance of Salmo salar against the sea louse Caligus rogercresseyi. In particular, we quantified the abundance of 2 pro-inflammatory cytokines, Tnfα and Il-8, and an antioxidant enzyme, Nkef, in Atlantic salmon skin and gill tissue from 21 families and 268 individuals by indirect ELISA. This covers a wide parasite load range from low or resistant (mean sea lice ± SE = 8.7 ± 0.9) to high or susceptible (mean sea lice ± SE = 43.3 ± 2.0). Our results showed that susceptible fish had higher levels of Nkef and Tnfα than resistant fish in their gills and skin, although gill Il-8 was higher in resistant fish, while no significant differences were found in the skin. Furthermore, moderate to very high heritable genetic variation was estimated for Nkef (h2 skin: 0.96 ± 0.14 and gills: 0.97 ± 0.11) and Tnfα (h2 skin: 0.53 ± 0.17 and gills: 0.32 ± 0.14), but not for Il-8 (h2 skin: 0.22 ± 0.12 ns and gills: 0.09 ± 0.08 ns). This work provides evidence that Nkef and Tnfα protein expressions are highly heritable and related to resistance against sea lice in Atlantic salmon.

Tunable Magnetic Properties of Interconnected Permalloy Nanowire Networks

In this study, we investigate the magnetic properties of interconnected permalloy nanowire networks using micromagnetic simulations. The effects of interconnectivity on the hysteresis curves, coercivity, and remanence of the nanowire networks are analyzed. Our results reveal intriguing characteristics of the hysteresis curves, including nonmonotonic behaviors of coercivity as a function of the position of horizontal nanowires relative to vertical nanowires. By introducing horizontal nanowires at specific positions, the coercivity of the nanowire networks can be enhanced without altering the material composition. The normalized remanence remains relatively constant regardless of the position of the horizontal wires, although it is lower in the interconnected nanowire arrays compared to nonconnected arrays. These findings provide valuable insights into the design and optimization of nanowire networks for applications requiring tailored magnetic properties.

Toxicity Mechanisms of Copper Nanoparticles and Copper Surfaces on Bacterial Cells and Viruses

Copper is a metal historically used to prevent infections. One of the most relevant challenges in modern society are infectious disease outbreaks, where copper-based technologies can play a significant role. Currently, copper nanoparticles and surfaces are the most common antimicrobial copper-based technologies. Despite the widespread use of copper on nanoparticles and surfaces, the toxicity mechanism(s) explaining their unique antimicrobial properties are not entirely known. In general, toxicity effects described in bacteria and fungi involve the rupture of membranes, accumulation of ions inside the cell, protein inactivation, and DNA damage. A few studies have associated Cu-toxicity with ROS production and genetic material degradation in viruses. Therefore, understanding the mechanisms of the toxicity of copper nanoparticles and surfaces will contribute to developing and implementing efficient antimicrobial technologies to combat old and new infectious agents that can lead to disease outbreaks such as COVID-19. This review summarizes the current knowledge regarding the microbial toxicity of copper nanoparticles and surfaces and the gaps in this knowledge. In addition, we discuss potential applications derived from discovering new elements of copper toxicity, such as using different molecules or modifications to potentiate toxicity or antimicrobial specificity.

Role of Rahnella aquatilis AZO16M2 in Phosphate Solubilization and Ex Vitro Acclimatization of Musa acuminata var. Valery

Rahnella aquatilis AZO16M2, was characterized for its phosphate solubilization capacity to improve the establishment and survival of Musa acuminata var. Valery seedlings under ex-acclimation. Three phosphorus sources (Rock Phosphate (RF), Ca3(PO4)2 and K2HPO4) and two types of substrate (sand:vermiculite (1:1) and Premix N°8) were selected. The factorial analysis of variance (p < 0.05) showed that R. aquatilis AZO16M2 (OQ256130) solubilizes Ca3(PO4)2 in solid medium, with a Solubilization Index (SI) of 3.77 at 28 °C (pH 6.8). In liquid medium, it was observed that R. aquatilis produced 29.6 mg/L soluble P (pH 4.4), and synthesized organic acids (oxalic, D-gluconic, 2-ketogluconic and malic), Indole Acetic Acid (IAA) (33.90 ppm) and siderophores (+). Additionally, acid and alkaline phosphatases (2.59 and 2.56 µg pNP/mL/min) were detected. The presence of the pyrroloquinoline-quinone (PQQ) cofactor gene was confirmed. After inoculating AZO16M2 to M. acuminata in sand:vermiculite with RF, the chlorophyll content was 42.38 SPAD (Soil Plant Analysis Development). Aerial fresh weight (AFW), aerial dry weight (ADW) and root dry weight (RDW) were superior to the control by 64.15%, 60.53% and 43.48%, respectively. In Premix N°8 with RF and R. aquatilis, 8.91% longer roots were obtained, with 35.58% and 18.76% more AFW and RFW compared with the control as well as 94.45 SPAD. With Ca3(PO4)2, values exceeded the control by 14.15% RFW, with 45.45 SPAD. Rahnella aquatilis AZO16M2 favored the ex-climatization of M. acuminata through improving seedling establishment and survival.

Cytotoxic Activity, Topoisomerase I Inhibition and In Silico Studies of New Sesquiterpene-aryl Ester Derivatives of (-) Drimenol

In this study, we aimed to evaluate two sets of sesquiterpene-aryl derivatives linked by an ester bond, their cytotoxic activities, and their capacity to activate caspases 3/7 and inhibit human topoisomerase I (TOP1). A total of 13 compounds were synthesized from the natural sesquiterpene (-)-drimenol and their cytotoxic activity was evaluated in vitro against three cancer cell lines: PC-3 (prostate cancer), HT-29 (colon cancer), MCF-7 (breast cancer), and an immortalized non-tumoral cell line (MCF-10). From the results, it was observed that 6a was the most promising compound due to its cytotoxic effect on three cancer cell lines and its selectivity, 6a was 100-fold more selective than 5-FU in MCF-7 and 20-fold in PC-3. It was observed that 6a also induced apoptosis by caspases 3/7 activity using a Capsase-Glo-3/7 assay kit and inhibited TOP1. A possible binding mode of 6a in a complex with TOP1-DNA was proposed by docking and molecular dynamics studies. In addition, 6a was predicted to have a good pharmacokinetic profile for oral administration. Therefore, through this study, it was demonstrated that the drimane scaffold should be considered in the search of new antitumoral agents.

Assessing temperature-based adaptation limits to climate change of temperate perennial fruit crops

Temperate perennial fruit and nut trees play varying roles in world food diversity-providing edible oils and micronutrient, energy, and protein dense foods. In addition, perennials reuse significant amounts of biomass each year providing a unique resilience. But they also have a unique sensitivity to seasonal temperatures, requiring a period of dormancy for successful growing season production. This paper takes a global view of five temperate tree fruit crops-apples, cherries, almonds, olives, and grapes-and assesses the effects of future temperature changes on thermal suitability. It uses climate data from five earth system models for two CMIP6 climate scenarios and temperature-related indices of stress to indicate potential future areas where crops cannot be grown and highlight potential new suitable regions. The loss of currently suitable areas and new additions in new locations varies by scenario. In the southern hemisphere (SH), end-century (2081-2100) suitable areas under the SSP 5-8.5 scenario decline by more than 40% compared to a recent historical period (1991-2010). In the northern hemisphere (NH) suitability increases by 20% to almost 60%. With SSP1-2.6, however, the changes are much smaller with SH area declining by about 25% and NH increasing by about 10%. The results suggest substantial restructuring of global production for these crops. Essentially, climate change shifts temperature-suitable locations toward higher latitudes. In the SH, most of the historically suitable areas were already at the southern end of the landmass limiting opportunities for adaptation. If breeding efforts can bring chilling requirements for the major cultivars closer to that currently seen in some cultivars, suitable areas at the end of the century are greater, but higher summer temperatures offset the extent. The high value of fruit crops provides adaptation opportunities such as cultivar selection, canopy cooling using sprinklers, shade netting, and precision irrigation.

Interaction between Cigarette Smoke and Human Papillomavirus 16 E6/E7 Oncoproteins to Induce SOD2 Expression and DNA Damage in Head and Neck Cancer

Even though epidemiological studies suggest that tobacco smoking and high-risk human papillomavirus (HR-HPV) infection are mutually exclusive risk factors for developing head and neck cancer (HNC), a portion of subjects who develop this heterogeneous group of cancers are both HPV-positive and smokers. Both carcinogenic factors are associated with increased oxidative stress (OS) and DNA damage. It has been suggested that superoxide dismutase 2 (SOD2) can be independently regulated by cigarette smoke and HPV, increasing adaptation to OS and tumor progression. In this study, we analyzed SOD2 levels and DNA damage in oral cells ectopically expressing HPV16 E6/E7 oncoproteins and exposed to cigarette smoke condensate (CSC). Additionally, we analyzed SOD2 transcripts in The Cancer Genome Atlas (TCGA) Head and Neck Cancer Database. We found that oral cells expressing HPV16 E6/E7 oncoproteins exposed to CSC synergistically increased SOD2 levels and DNA damage. Additionally, the SOD2 regulation by E6, occurs in an Akt1 and ATM-independent manner. This study suggests that HPV and cigarette smoke interaction in HNC promotes SOD2 alterations, leading to increased DNA damage and, in turn, contributing to development of a different clinical entity.

Experimental evidence of the anti-bacterial activity pathway of copper ion treatment on Mycobacterium avium subsp. paratuberculosis

Copper causes significant damage to the integrity of many bacteria, mainly at the DNA level, through its redox states, as well as its reactive oxygen species (ROS) generating capacity at the cellular level. But whether these mechanisms also apply to Mycobacterium avium subsp. paratuberculosis (MAP) is unknown. In the present study, we have evaluated whether copper ions produce damage at the DNA level of MAP, either through their redox states or through ROS production. MAP-spiked PBS was first supplemented with different copper chelators (2) and ROS antioxidants (3), followed by treatment with copper ions at 942 ppm. MAP DNA integrity (qPCR, magnetic phage separation) was then evaluated. We found that bathocuproine (BCS), as a chelator, and D-mannitol, as an antioxidant of hydroxyl radicals, had a significant protective effect (P < 0.05) on DNA molecules, and that EDTA, as a chelator, and D-mannitol, as an antioxidant had a significant positive effect (P < 0.05) on the viability of this pathogen in contrast to the control and other chelators and anti-oxidants used. In light of the reported findings, it may be concluded that copper ions within MAP cells are directly related to MAP DNA damage.

First molecular detection of Equine Herpesvirus type 3 (EHV-3) in Chile

Equine coital rash (ECE) is a highly contagious benign infection that induces lesions on external genitals, and it is caused by the equine herpesvirus type 3 (EHV-3). Although the disease is globally distributed, its presence in Chile has not been documented from a genetic point of view. Here, we performed polymerase chain reaction screenings for EHV-3 in lesions of external genitals in four horses belonging to a riding station at Bulnes, Ñuble Region, Chile. We sequenced a fragment of the glycoprotein G (gG) gene from three horses with clinical signs of ECE. The sequences were identical between them and 99.7% similar to a haplotype of EHV-3 detected in Brazil, and phylogenetically related with homologue from Japan, Russia and Brazil. Our results show the presence of EHV-3 for the first time in horses with ECE in Chile.

Transmission estimation at the quantum Cramér-Rao bound with macroscopic quantum light

The field of quantum metrology seeks to apply quantum techniques and/or resources to classical sensing approaches with the goal of enhancing the precision in the estimation of a parameter beyond what can be achieved with classical resources. Theoretically, the fundamental minimum uncertainty in the estimation of a parameter for a given probing state is bounded by the quantum Cramér-Rao bound. From a practical perspective, it is necessary to find physical measurements that can saturate this fundamental limit and to show experimentally that it is possible to perform measurements with the required precision to do so. Here we perform experiments that saturate the quantum Cramér-Rao bound for transmission estimation over a wide range of transmissions when probing the system under study with a continuous wave bright two-mode squeezed state. To properly take into account the imperfections in the generation of the quantum state, we extend our previous theoretical results to incorporate the measured properties of the generated quantum state. For our largest transmission level of 84%, we show a 62% reduction over the optimal classical protocol in the variance in transmission estimation when probing with a bright two-mode squeezed state with -8 dB of intensity-difference squeezing. Given that transmission estimation is an integral part of many sensing protocols, such as plasmonic sensing, spectroscopy, calibration of the quantum efficiency of detectors, etc., the results presented promise to have a significant impact on a number of applications in various fields of research.

Celebrating Higher Education's 50 years: trends, absences, and opportunities

The journal, Higher Education (HE), was established in 1972 and is currently one of the leading international journals in higher education studies. By using bibliometric techniques, a systematic review, and a social network analysis, this review article provides an overview of the main patterns of publications in HE during its history. The findings show that (i) the volume of articles has been continuously increasing, with a particular marked uplift since 2007; (ii) while single-authored articles have dominated the publication pattern, collaborative articles have shown a particular growth over the last decade; (iii) the USA, the UK, and Australia have dominated the journal in terms of the number of articles, international collaboration, and the most prolific authors; (iv) while Chinese authors have become more evident, there has been a near-absence of contributions from Latin America, Eastern Europe, and most of Africa; (v) in the entire history of HE, there has been a gender imbalance (in favour of male authors) across the most cited articles, but this pattern has changed in the last decade and; (vi) both teaching and learning and system policy have been key research themes in the journal although internationalisation and the student experience have recently gained traction. These patterns of publication in HE, with their imbalances and absences, suggest several challenges ahead.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10734-022-00924-7.

Anaerobiosis favors biosynthesis of single and multi-element nanostructures

Herein we report the use of an environmental multimetal(loid)-resistant strain, MF05, to biosynthesize single- or multi-element nanostructures under anaerobic conditions. Inorganic nanostructure synthesis typically requires methodologies and conditions that are harsh and environmentally hazardous. Thus, green/eco-friendly procedures are desirable, where the use of microorganisms and their extracts as bionanofactories is a reliable strategy. First, MF05 was entirely sequenced and identified as an Escherichia coli-related strain with some genetic differences from the traditional BW25113. Secondly, we compared the CdS nanostructure biosynthesis by whole-cell in a design defined minimal culture medium containing sulfite as the only sulfur source to obtain sulfide reduction from a low-cost chalcogen reactant. Under anaerobic conditions, this process was greatly favored, and irregular CdS (ex. 370 nm; em. 520-530 nm) was obtained. When other chalcogenites were tested (selenite and tellurite), only spherical Se0 and elongated Te0 nanostructures were observed by TEM and analyzed by SEM-EDX. In addition, enzymatic-mediated chalcogenite (sulfite, selenite, and tellurite) reduction was assessed by using MF05 crude extracts in anaerobiosis; similar results for nanostructures were obtained; however Se0 and Te0 formation were more regular in shape and cleaner (with less background). Finally, the in vitro nanostructure biosynthesis was assessed with salts of Ag, Au, Cd, and Li alone or in combination with chalcogenites. Several single or binary nanostructures were detected. Our results showed that MF05 is a versatile anaerobic bionanofactory for different types of inorganic NS. synthesis.

Phenoxy- and Phenylamino-Heterocyclic Quinones: Synthesis and Preliminary Anti-Pancreatic Cancer Activity

The successful application of fragment-based drug discovery strategy for the efficient synthesis of phenoxy- or phenylamino-2-phenyl-benzofuran, -benzoxazole and -benzothiazole quinones is described. Interestingly, in the final step of the synthesis of the target compounds, unusual results were observed on the regiochemistry of the reaction of bromoquinones with phenol and aniline. A theoretical study was carried out for better understanding the factors that control the regiochemistry of these reactions. The substituted heterocyclic quinones were evaluated in vitro to determine their cytotoxicity by the MTT method in three pancreatic cancer cell lines (MIA-PaCa-2, BxPC-3, and AsPC-1). Phenoxy benzothiazole quinone 26a showed potent cytotoxic activity against BxPC-3 cell lines, while phenylamino benzoxazole quinone 20 was the most potent on MIA-PaCa-2 cells. Finally, electrochemical properties of these quinones were determined to correlate with a potential mechanism of action. All these results, indicate that the phenoxy quinone fragment led to compounds with increased activity against pancreatic cancer cells.

Peptide Targeted Gold Nanoplatform Carrying miR-145 Induces Antitumoral Effects in Ovarian Cancer Cells

One of the recent attractive therapeutic approaches for cancer treatment is restoring downregulated microRNAs. They play an essential muti-regulatory role in cellular processes such as proliferation, differentiation, survival, apoptosis, cell cycle, angiogenesis, and metastasis, among others. In this study, a gold nanoplatform (GNPF) carrying miR-145, a downregulated microRNA in many cancer types, including epithelial ovarian cancer, was designed and synthesized. For targeting purposes, the GNPF was functionalized with the FSH33 peptide, which provided selectivity for ovarian cancer, and loaded with the miR-145 to obtain the nanosystem GNPF-miR-145. The GNPF-mir-145 was selectively incorporated in A2780 and SKOV3 cells and significantly inhibited cell viability and migration and exhibited proliferative and anchor-independent growth capacities. Moreover, it diminished VEGF release and reduced the spheroid size of ovarian cancer through the damage of cell membranes, thus decreasing cell viability and possibly activating apoptosis. These results provide important advances in developing miR-based therapies using nanoparticles as selective vectors and provide approaches for in vivo evaluation.

Discriminative Capacity of CT Volumetry to Identify Autonomous Cortisol Secretion in Incidental Adrenal Adenomas

CONTEXT

Incidentally discovered adrenal adenomas are common. Assessment for possible autonomous cortisol excess (ACS) is warranted for all adrenal adenomas, given the association with increased cardiometabolic disease.

OBJECTIVE

To evaluate the discriminatory capacity of 3-dimensional volumetry on computed tomography (CT) to identify ACS.

METHODS

Two radiologists, blinded to hormonal levels, prospectively analyzed CT images of 149 adult patients with unilateral, incidentally discovered, adrenal adenomas. Diameter and volumetry of the adenoma, volumetry of the contralateral adrenal gland, and the adenoma volume-to-contralateral gland volume (AV/CV) ratio were measured. ACS was defined as cortisol ≥ 1.8 mcg/dL after 1-mg dexamethasone suppression test (DST) and a morning ACTH ≤ 15. pg/mL.

RESULTS

We observed that ACS was diagnosed in 35 (23.4%) patients. Cortisol post-DST was positively correlated with adenoma diameter and volume, and inversely correlated with contralateral adrenal gland volume. Cortisol post-DST was positively correlated with the AV/CV ratio (r = 0.46, P < 0.001) and ACTH was inversely correlated (r = -0.28, P < 0.001). The AV/CV ratio displayed the highest odds ratio (1.40; 95% CI, 1.18-1.65) and area under curve (0.91; 95% CI, 0.86-0.96) for predicting ACS. An AV/CV ratio ≥ 1 (48% of the cohort) had a sensitivity of 97% and a specificity of 70% to identify ACS.

CONCLUSION

CT volumetry of adrenal adenomas and contralateral adrenal glands has a high discriminatory capacity to identify ACS. The combination of this simple and low-cost radiological phenotyping can supplement biochemical testing to substantially improve the identification of ACS.

An international, interlaboratory ring trial confirms the feasibility of an extraction-less "direct" RT-qPCR method for reliable detection of SARS-CoV-2 RNA in clinical samples

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) is used worldwide to test and trace the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). "Extraction-less" or "direct" real time-reverse transcription polymerase chain reaction (RT-PCR) is a transparent and accessible qualitative method for SARS-CoV-2 detection from nasopharyngeal or oral pharyngeal samples with the potential to generate actionable data more quickly, at a lower cost, and with fewer experimental resources than full RT-qPCR. This study engaged 10 global testing sites, including laboratories currently experiencing testing limitations due to reagent or equipment shortages, in an international interlaboratory ring trial. Participating laboratories were provided a common protocol, common reagents, aliquots of identical pooled clinical samples, and purified nucleic acids and used their existing in-house equipment. We observed 100% concordance across laboratories in the correct identification of all positive and negative samples, with highly similar cycle threshold values. The test also performed well when applied to locally collected patient nasopharyngeal samples, provided the viral transport media did not contain charcoal or guanidine, both of which appeared to potently inhibit the RT-PCR reaction. Our results suggest that direct RT-PCR assay methods can be clearly translated across sites utilizing readily available equipment and expertise and are thus a feasible option for more efficient COVID-19 coronavirus disease testing as demanded by the continuing pandemic.

Oxidative Crosslinking of Peptides and Proteins: Mechanisms of Formation, Detection, Characterization and Quantification

Covalent crosslinks within or between proteins play a key role in determining the structure and function of proteins. Some of these are formed intentionally by either enzymatic or molecular reactions and are critical to normal physiological function. Others are generated as a consequence of exposure to oxidants (radicals, excited states or two-electron species) and other endogenous or external stimuli, or as a result of the actions of a number of enzymes (e.g., oxidases and peroxidases). Increasing evidence indicates that the accumulation of unwanted crosslinks, as is seen in ageing and multiple pathologies, has adverse effects on biological function. In this article, we review the spectrum of crosslinks, both reducible and non-reducible, currently known to be formed on proteins; the mechanisms of their formation; and experimental approaches to the detection, identification and characterization of these species.

Review on Sol-Gel Synthesis of Perovskite and Oxide Nanomaterials

Sol-Gel is a low cost, well-established and flexible synthetic route to produce a wide range of micro- and nanostructures. Small variations in pH, temperature, precursors, time, pressure, atmosphere, among others, can lead to a wide family of compounds that share the same molecular structures. In this work, we present a general review of the synthesis of LaMnO3, SrTiO3, BaTiO3 perovskites and zinc vanadium oxides nanostructures based on Sol-Gel method. We discuss how small changes in the parameters of the synthesis can modify the morphology, shape, size, homogeneity, aggregation, among others, of the products. We also discuss the different precursors, solvents, working temperature, reaction times used throughout the synthesis. In the last section, we present novel uses of Sol-Gel with organic materials with emphasis on carbon-based compounds. All with a perspective to improve the method for future applications in different technological fields.

Locus-specific analysis of Transposable Elements during the progression of ALS in the SOD1G93A mouse model

Transposable Elements (TEs) are ubiquitous genetic elements with the ability to move within a genome. TEs contribute to a large fraction of the repetitive elements of a genome, and because of their nature, they are not routinely analyzed in RNA-Seq gene expression studies. Amyotrophic Lateral Sclerosis (ALS) is a lethal neurodegenerative disease, and a well-accepted model for its study is the mouse harboring the human SOD1G93A mutant. In this model, landmark stages of the disease can be recapitulated at specific time points, making possible to understand changes in gene expression across time. While there are several works reporting TE activity in ALS models, they have not explored their activity through the disease progression. Moreover, they have done it at the expense of losing their locus of expression. Depending on their genomic location, TEs can regulate genes in cis and in trans, making locus-specific analysis of TEs of importance in order to understand their role in modulating gene expression. Particularly, the locus-specific role of TEs in ALS has not been fully elucidated. In this work, we analyzed publicly available RNA-Seq datasets of the SOD1G93A mouse model, to understand the locus-specific role of TEs. We show that TEs become up-regulated at the early stages of the disease, and via statistical associations, we speculate that they can regulate several genes, which in turn might be contributing to the genetic dysfunction observed in ALS.

Effects of the sigma-1 receptor agonist blarcamesine in a murine model of fragile X syndrome: neurobehavioral phenotypes and receptor occupancy

Fragile X syndrome (FXS), a disorder of synaptic development and function, is the most prevalent genetic form of intellectual disability and autism spectrum disorder. FXS mouse models display clinically-relevant phenotypes, such as increased anxiety and hyperactivity. Despite their availability, so far advances in drug development have not yielded new treatments. Therefore, testing novel drugs that can ameliorate FXS' cognitive and behavioral impairments is imperative. ANAVEX2-73 (blarcamesine) is a sigma-1 receptor (S1R) agonist with a strong safety record and preliminary efficacy evidence in patients with Alzheimer's disease and Rett syndrome, other synaptic neurodegenerative and neurodevelopmental disorders. S1R's role in calcium homeostasis and mitochondrial function, cellular functions related to synaptic function, makes blarcamesine a potential drug candidate for FXS. Administration of blarcamesine in 2-month-old FXS and wild type mice for 2 weeks led to normalization in two key neurobehavioral phenotypes: open field test (hyperactivity) and contextual fear conditioning (associative learning). Furthermore, there was improvement in marble-burying (anxiety, perseverative behavior). It also restored levels of BDNF, a converging point of many synaptic regulators, in the hippocampus. Positron emission tomography (PET) and ex vivo autoradiographic studies, using the highly selective S1R PET ligand [18F]FTC-146, demonstrated the drug's dose-dependent receptor occupancy. Subsequent analyses also showed a wide but variable brain regional distribution of S1Rs, which was preserved in FXS mice. Altogether, these neurobehavioral, biochemical, and imaging data demonstrates doses that yield measurable receptor occupancy are effective for improving the synaptic and behavioral phenotype in FXS mice. The present findings support the viability of S1R as a therapeutic target in FXS, and the clinical potential of blarcamesine in FXS and other neurodevelopmental disorders.

A New Smoothened Antagonist Bearing the Purine Scaffold Shows Antitumour Activity In Vitro and In Vivo

The Smoothened (SMO) receptor is the most druggable target in the Hedgehog (HH) pathway for anticancer compounds. However, SMO antagonists such as vismodegib rapidly develop drug resistance. In this study, new SMO antagonists having the versatile purine ring as a scaffold were designed, synthesised, and biologically tested to provide an insight to their mechanism of action. Compound 4s was the most active and the best inhibitor of cell growth and selectively cytotoxic to cancer cells. 4s induced cell cycle arrest, apoptosis, a reduction in colony formation and downregulation of PTCH and GLI1 expression. BODIPY-cyclopamine displacement assays confirmed 4s is a SMO antagonist. In vivo, 4s strongly inhibited tumour relapse and metastasis of melanoma cells in mice. In vitro, 4s was more efficient than vismodegib to induce apoptosis in human cancer cells and that might be attributed to its dual ability to function as a SMO antagonist and apoptosis inducer.

Smartphone screen testing, a novel pre-diagnostic method to identify SARS-CoV-2 infectious individuals

The COVID-19 pandemic will likely take years to control globally, and constant epidemic surveillance will be required to limit the spread of SARS-CoV-2, especially considering the emergence of new variants that could hamper the effect of vaccination efforts. We developed a simple and robust - Phone Screen Testing (PoST) - method to detect SARS-CoV-2-positive individuals by RT-PCR testing of smartphone screen swab samples. We show that 81.3-100% of individuals with high-viral-load SARS-CoV-2 nasopharyngeal-positive samples also test positive for PoST, suggesting this method is effective in identifying COVID-19 contagious individuals. Furthermore, we successfully identified polymorphisms associated with SARS-CoV-2 Alpha, Beta, and Gamma variants, in SARS-CoV-2-positive PoST samples. Overall, we report that PoST is a new non-invasive, cost-effective, and easy-to-implement smartphone-based smart alternative for SARS-CoV-2 testing, which could help to contain COVID-19 outbreaks and identification of variants of concern in the years to come.

Thermal performance of the Chagas disease vector, Triatoma infestans, under thermal variability

Vector-borne diseases (VBD) are particularly susceptible to climate change because most of the diseases' vectors are ectotherms, which themselves are susceptible to thermal changes. The Chagas disease is one neglected tropical disease caused by the protozoan parasite, Trypanosoma cruzi. One of the main vectors of the Chagas disease in South America is Triatoma infestans, a species traditionally considered to be restricted to domestic or peridomestic habitats, but sylvatic foci have also been described along its distribution. The infestation of wild individuals, together with the projections of environmental changes due to global warming, urge the need to understand the relationship between temperature and the vector's performance. Here, we evaluated the impact of temperature variability on the thermal response of T. infestans. We acclimated individuals to six thermal treatments for five weeks to then estimate their thermal performance curves (TPCs) by measuring the walking speed of the individuals. We found that the TPCs varied with thermal acclimation and body mass. Individuals acclimated to a low and variable ambient temperature (18°C ± 5°C) exhibited lower performances than those individuals acclimated to an optimal temperature (27°C ± 0°C); while those individuals acclimated to a low but constant temperature (18°C ± 0°C) did not differ in their maximal performance from those at an optimal temperature. Additionally, thermal variability (i.e., ± 5°C) at a high temperature (30°C) increased performance. These results evidenced the plastic response of T. infestans to thermal acclimation. This plastic response and the non-linear effect of thermal variability on the performance of T. infestans posit challenges when predicting changes in the vector's distribution range under climate change.

Analysis of the quinoa genome reveals conservation and divergence of the flowering pathways

Quinoa (Chenopodium quinoa Willd.) is a grain crop grown in the Andes renowned as a highly nutritious plant exhibiting tolerance to abiotic stress such as drought, cold and high salinity. Quinoa grows across a range of latitudes corresponding to differing day lengths, suggesting regional adaptations of flowering regulation. Improved understanding and subsequent modification of the flowering process, including flowering time, ensuring high yields, is one of the key factors behind expansion of cultivation zones and goals of the crop improvement programs worldwide. However, our understanding of the molecular basis of flower initiation and development in quinoa is limited. Here, we use a computational approach to perform genome-wide identification and analysis of 611 orthologues of the Arabidopsis thaliana flowering genes. Conservation of the genes belonging to the photoperiod, gibberellin and autonomous pathways was observed, while orthologues of the key genes found in the vernalisation pathway (FRI, FLC) were absent from the quinoa genome. Our analysis indicated that on average each Arabidopsis flowering gene has two orthologous copies in quinoa. Several genes including orthologues of MIF1, FT and TSF were identified as homologue-rich genes in quinoa. We also identified 459 quinoa-specific genes uniquely expressed in the flower and/or meristem, with no known orthologues in other species. The genes identified provide a resource and framework for further studies of flowering in quinoa and related species. It will serve as valuable resource for plant biologists, crop physiologists and breeders to facilitate further research and establishment of modern breeding programs for quinoa.

Reverse engineering directed gene regulatory networks from transcriptomics and proteomics data of biomining bacterial communities with approximate Bayesian computation and steady-state signalling simulations

BACKGROUND

Network inference is an important aim of systems biology. It enables the transformation of OMICs datasets into biological knowledge. It consists of reverse engineering gene regulatory networks from OMICs data, such as RNAseq or mass spectrometry-based proteomics data, through computational methods. This approach allows to identify signalling pathways involved in specific biological functions. The ability to infer causality in gene regulatory networks, in addition to correlation, is crucial for several modelling approaches and allows targeted control in biotechnology applications.

METHODS

We performed simulations according to the approximate Bayesian computation method, where the core model consisted of a steady-state simulation algorithm used to study gene regulatory networks in systems for which a limited level of details is available. The simulations outcome was compared to experimentally measured transcriptomics and proteomics data through approximate Bayesian computation.

RESULTS

The structure of small gene regulatory networks responsible for the regulation of biological functions involved in biomining were inferred from multi OMICs data of mixed bacterial cultures. Several causal inter- and intraspecies interactions were inferred between genes coding for proteins involved in the biomining process, such as heavy metal transport, DNA damage, replication and repair, and membrane biogenesis. The method also provided indications for the role of several uncharacterized proteins by the inferred connection in their network context.

CONCLUSIONS

The combination of fast algorithms with high-performance computing allowed the simulation of a multitude of gene regulatory networks and their comparison to experimentally measured OMICs data through approximate Bayesian computation, enabling the probabilistic inference of causality in gene regulatory networks of a multispecies bacterial system involved in biomining without need of single-cell or multiple perturbation experiments. This information can be used to influence biological functions and control specific processes in biotechnology applications.

Structural characterization of the saxitoxin-targeting APTSTX1 aptamer using optical tweezers and molecular dynamics simulations

Optical tweezers have enabled the exploration of picoNewton forces and dynamics in single-molecule systems such as DNA and molecular motors. In this work, we used optical tweezers to study the folding/unfolding dynamics of the APTSTX1-aptamer, a single-stranded DNA molecule with high affinity for saxitoxin (STX), a lethal neurotoxin. By measuring the transition force during (un)folding processes, we were able to characterize and distinguish the conformational changes of this aptamer in the presence of magnesium ions and toxin. This work was supported by molecular dynamics (MD) simulations to propose an unfolding mechanism of the aptamer-Mg+2 complex. Our results are a step towards the development of new aptamer-based STX sensors that are potentially cheaper and more sensitive than current alternatives.

The effect of seminal plasma β-NGF on follicular fluid hormone concentration and gene expression of steroidogenic enzymes in llama granulosa cells

BACKGROUND

Nerve growth factor (β-NGF) from llama seminal plasma has been described as a potent ovulatory and luteotrophic molecule after intramuscular or intrauterine infusion in llamas and alpacas. We tested the hypothesis that systemic administration of purified β-Nerve Growth Factor (β-NGF) during the preovulatory stage will up-regulate steroidogenic enzymes and Vascular Endothelial Growth Factor (VEGF) gene expression in granulosa cells inducing a change in the progesterone/estradiol ratio in the follicular fluid in llamas.

METHODS

Experiment I: Female llamas (n = 64) were randomly assigned to receive an intramuscular administration of: a) 50 μg gonadorelin acetate (GnRH, Ovalyse, Pfizer Chile SA, Santiago, Chile, n = 16), b) 1.0 mg of purified llama β-NGF (n = 16), or c) 1 ml phosphate buffered saline (PBS, negative control group, n = 16). An additional group of llamas (n = 16) were mated with a fertile male. Follicular fluid and granulosa cells were collected from the preovulatory follicle at 10 or 20 h after treatment (Time 0 = administration of treatment, n = 8/treatment/time point) to determine progesterone/estradiol concentration and steroidogenic enzymes and VEGF gene expression at both time points. Experiment II: Granulosa cells were collected from preovulatory follicles from llamas (n = 24) using ultrasound-guided transvaginal follicle aspiration for in vitro culture to determine mRNA relative expression of Steroidogenic Acute Regulatory Protein (StAR) and VEGF at 10 or 20 h (n = 4 replicates) and progesterone secretion at 48 h (n = 4 replicates) after LH or β-NGF treatment.

RESULTS

Experiment I: There was a significant increase in the progesterone/estradiol ratio in mated llamas or treated with GnRH or purified β-NGF. There was a significant downregulation in the mRNA expression of Aromatase (CYP19A1/P450 Arom) for both time points in llamas mated or treated with GnRH or llama purified β-NGF with respect to the control group. All treatments except β-NGF (20 h) significantly up regulated the mRNA expression of 3-beta-hydroxysteroid dehydrogenase (HSD3B) whereas the expression of StAR and Side-Chain cleavage enzyme (CYP11A1/P450scc) where significantly up regulated only by mating (20 h), or β-NGF at 10 or 20 h after treatment. VEGF was up regulated only in those llamas submitted to mating (10 h) or treated with purified β-NGF (10 and 20 h). Experiment II: Only β-NGF treatment induced an increase of mRNA abundance of StAR from llama granulosa cells at 20 h of in vitro culture. There was a significant increase on mRNA abundance of VEGF at 10 and 20 h of in vitro culture from granulosa cells treated with β-NGF whereas LH treatment increases VEGF mRNA abundance only at 20 h of in vitro culture. In addition, there was a significant increase on progesterone secretion from llama granulosa cells 48 h after LH or β-NGF treatment.

CONCLUSIONS

Systemic administration of purified β-NGF from llama seminal fluid induced a rapid shift from estradiol to progesterone production in the preovulatory follicle. Differences in gene expression patterns of steroidogenic enzymes between GnRH and mated or β-NGF-treated llamas suggest local effects of seminal components on the preovulatory follicle.

An extracellular cation coordination site influences ion conduction of OsHKT2;2

BACKGROUND

HKT channels mediate sodium uniport or sodium and potassium symport in plants. Monocotyledons express a higher number of HKT proteins than dicotyledons, and it is only within this clade of HKT channels that cation symport mechanisms are found. The prevailing ion composition in the extracellular medium affects the transport abilities of various HKT channels by changing their selectivity or ion transport rates. How this mutual effect is achieved at the molecular level is still unknown. Here, we built a homology model of the monocotyledonous OsHKT2;2, which shows sodium and potassium symport activity. We performed molecular dynamics simulations in the presence of sodium and potassium ions to investigate the mutual effect of cation species.

RESULTS

By analyzing ion-protein interactions, we identified a cation coordination site on the extracellular protein surface, which is formed by residues P71, D75, D501 and K504. Proline and the two aspartate residues coordinate cations, while K504 forms salt bridges with D75 and D501 and may be involved in the forwarding of cations towards the pore entrance. Functional validation via electrophysiological experiments confirmed the biological relevance of the predicted ion coordination site and identified K504 as a central key residue. Mutation of the cation coordinating residues affected the functionality of HKT only slightly. Additional in silico mutants and simulations of K504 supported experimental results.

CONCLUSION

We identified an extracellular cation coordination site, which is involved in ion coordination and influences the conduction of OsHKT2;2. This finding proposes a new viewpoint in the discussion of how the mutual effect of variable ion species may be achieved in HKT channels.

Herbivore resistance in congeneric and sympatric Nothofagus species is not related to leaf habit

PREMISE

Two fundamental hypotheses on herbivore resistance and leaf habit are the resource availability hypothesis (RAH) and the carbon-nutrient balance hypothesis (CNBH). The RAH predicts higher constitutive resistance by evergreens, and the CNBH predicts higher induced resistance by deciduous species. Although support for these hypotheses is mixed, they have rarely been examined in congeneric species.

METHODS

We compared leaf constitutive and induced resistance (as leaf polyphenol and tannin concentrations, and as damage level in non-choice experiments) and leaf traits associated with herbivory of coexisting Nothofagus species using (1) a defoliation experiment and (2) natural defoliation caused by an outbreak of a common defoliator of Nothofagus species.

RESULTS

In the defoliation experiment, polyphenol and tannin concentrations were similar between deciduous and evergreen species; regardless of leaf habit, polyphenols increased in response to defoliation. In the natural defoliation survey, N. pumilio (deciduous) had significantly higher herbivory, lower carbon/nitrogen ratio and leaf mass per area, and higher nitrogen and phosphorus concentrations than N. betuloides (evergreen); N. antarctica (deciduous) had intermediate values. Polyphenol concentrations and herbivore resistance indicated by the non-choice experiment were lower in N. pumilio than in N. antarctica and N. betuloides, which had similar values.

CONCLUSIONS

Higher herbivory in N. pumilio was associated with a higher nutritional value and a lower level of leaf carbon-based defenses compared to both the evergreen and the other deciduous species, indicating that herbivore resistance in Nothofagus species cannot be attributed to only leaf habit as predicted by the RAH or CNBH.

Nutrient exchange in arbuscular mycorrhizal symbiosis from a thermodynamic point of view

To obtain insights into the dynamics of nutrient exchange in arbuscular mycorrhizal (AM) symbiosis, we modelled mathematically the two-membrane system at the plant-fungus interface and simulated its dynamics. In computational cell biology experiments, the full range of nutrient transport pathways was tested for their ability to exchange phosphorus (P)/carbon (C)/nitrogen (N) sources. As a result, we obtained a thermodynamically justified, independent and comprehensive model of the dynamics of the nutrient exchange at the plant-fungus contact zone. The predicted optimal transporter network coincides with the transporter set independently confirmed in wet-laboratory experiments previously, indicating that all essential transporter types have been discovered. The thermodynamic analyses suggest that phosphate is released from the fungus via proton-coupled phosphate transporters rather than anion channels. Optimal transport pathways, such as cation channels or proton-coupled symporters, shuttle nutrients together with a positive charge across the membranes. Only in exceptional cases does electroneutral transport via diffusion facilitators appear to be plausible. The thermodynamic models presented here can be generalized and adapted to other forms of mycorrhiza and open the door for future studies combining wet-laboratory experiments with computational simulations to obtain a deeper understanding of the investigated phenomena.

Human-environmental drivers and impacts of the globally extreme 2017 Chilean fires

In January 2017, hundreds of fires in Mediterranean Chile burnt more than 5000 km², an area nearly 14 times the 40-year mean. We contextualize these fires in terms of estimates of global fire intensity using MODIS satellite record, and provide an overview of the climatic factors and recent changes in land use that led to the active fire season and estimate the impact of fire emissions to human health. The primary fire activity in late January coincided with extreme fire weather conditions including all-time (1979-2017) daily records for the Fire Weather Index (FWI) and maximum temperature, producing some of the most energetically intense fire events on Earth in the last 15-years. Fire activity was further enabled by a warm moist growing season in 2016 that interrupted an intense drought that started in 2010. The land cover in this region had been extensively modified, with less than 20% of the original native vegetation remaining, and extensive plantations of highly flammable exotic Pinus and Eucalyptus species established since the 1970s. These plantations were disproportionally burnt (44% of the burned area) in 2017, and associated with the highest fire severities, as part of an increasing trend of fire extent in plantations over the past three decades. Smoke from the fires exposed over 9.5 million people to increased concentrations of particulate air pollution, causing an estimated 76 premature deaths and 209 additional admissions to hospital for respiratory and cardiovascular conditions. This study highlights that Mediterranean biogeographic regions with expansive Pinus and Eucalyptus plantations and associated rural depopulation are vulnerable to intense wildfires with wide ranging social, economic, and environmental impacts, which are likely to become more frequent due to longer and more extreme wildfire seasons.

Diapause induces functional axonal regeneration after necrotic insult in C. elegans

Many neurons are unable to regenerate after damage. The ability to regenerate after an insult depends on life stage, neuronal subtype, intrinsic and extrinsic factors. C. elegans is a powerful model to test the genetic and environmental factors that affect axonal regeneration after damage, since its axons can regenerate after neuronal insult. Here we demonstrate that diapause promotes the complete morphological regeneration of truncated touch receptor neuron (TRN) axons expressing a neurotoxic MEC-4(d) DEG/ENaC channel. Truncated axons of different lengths were repaired during diapause and we observed potent axonal regrowth from somas alone. Complete morphological regeneration depends on DLK-1 but neuronal sprouting and outgrowth is DLK-1 independent. We show that TRN regeneration is fully functional since animals regain their ability to respond to mechanical stimulation. Thus, diapause induced regeneration provides a simple model of complete axonal regeneration which will greatly facilitate the study of environmental and genetic factors affecting the rate at which neurons die.