Role of Graphene in Surface Plasmon Resonance-Based Biosensors.

This work explores the transformative role of graphene in enhancing the performance of surface plasmon resonance (SPR)-based biosensors. The motivation for this review stems from the growing interest in the unique properties of graphene, such as high surface area, excellent electrical conductivity, and versatile functionalization capabilities, which offer significant potential to improve the sensitivity, specificity, and stability of SPR biosensors. This review systematically analyzes studies published between 2010 and 2023, covering key metrics of biosensor performance. The findings reveal that the integration of graphene consistently enhances sensitivity. Specificity, although less frequently reported numerically, showed promising results, with high specificity achieved at sub-nanomolar concentrations. Stability enhancements are also significant, attributed to the protective properties of graphene and improved biomolecule adsorption. Future research should focus on mechanistic insights, optimization of integration techniques, practical application testing, scalable fabrication methods, and comprehensive comparative studies. Our findings provide a foundation for future research, aiming to further optimize and harness the unique physical properties of graphene to meet the demands of sensitive, specific, stable, and rapid biosensing in various practical applications.

Risks to Human Health from Mercury in Gold Mining in the Coastal Region of Ecuador.

Artisanal and small-scale gold mining (ASGM) plays a crucial role in global gold production. However, the adoption of poor mining practices or the use of mercury (Hg) in gold recovery processes has generated serious environmental contamination events. The focus of this study is assessing the concentration of Hg in surface waters within the coastal region of Ecuador. The results are used to conduct a human health risk assessment applying deterministic and probabilistic methods, specifically targeting groups vulnerable to exposure in affected mining environments. Between April and June 2022, 54 water samples were collected from rivers and streams adjacent to mining areas to determine Hg levels. In the health risk assessment, exposure routes through water ingestion and dermal contact were considered for both adults and children, following the model structures outlined by the U.S. Environmental Protection Agency. The results indicate elevated Hg concentrations in two of the five provinces studied, El Oro and Esmeraldas, where at least 88% and 75% of the samples, respectively, exceeded the maximum permissible limit (MPL) set by Ecuadorian regulations for the preservation of aquatic life. Furthermore, in El Oro province, 28% of the samples exceeded the MPL established for drinking water quality. The high concentrations of Hg could be related to illegal mining activity that uses Hg for gold recovery. Regarding the human health risk assessment, risk values above the safe exposure limit were estimated. Children were identified as the most vulnerable receptor. Therefore, there is an urgent need to establish effective regulations that guarantee the protection of river users in potentially contaminated areas. Finally, it is important to continue investigating the contamination caused by human practices in the coastal region.

A new species of terrestrial toad of the Rhinellafestae group (Anura, Bufonidae) from the highlands of the Central Cordillera of the Andes of Colombia.

The genus Rhinella (Bufonidae) comprises 92 species of Neotropical toads. In Colombia, Rhinella is represented by 22 recognized species, of which nine belong to the Rhinellafestae group. Over the past decade, there has been increasing evidence of cryptic diversity within this group, particularly in the context of Andean forms. Specimens of Rhinella collected in high Andean forests on both slopes of the Central Cordillera in Colombia belong to an undescribed species, Rhinellakumandaysp. nov. Genetic analyses using the mitochondrial 16S rRNA gene indicated that the individuals belong to the festae species group. However, they can be distinguished from other closely related species such as Rhinellaparaguas and Rhinellatenrec by a combination of morphological traits including the presence of tarsal fold, a moderate body size, and substantial genetic divergence in the 16S rRNA gene (> 5%). Through this integrative approach, the specimens from the Central Cordillera of Colombia are considered an evolutionary divergent lineage that is sister to R.paraguas, and described as a new species. Rhinellakumandaysp. nov. is restricted to the Central Cordillera of Colombia inhabiting both slopes in the departments of Caldas and Tolima, in an elevational range between 2420 and 3758 m. With the recognition of this new species, the genus Rhinella now comprises 93 species with 23 of them found in Colombia, and ten species endemic to the country.

Electromagnetic fields effects on microbial growth in cocoa fermentation: A controlled experimental approach using established growth models.

Understanding the effects of electromagnetic fields is crucial in the fermentation of cocoa beans, since through precise control of fermentation conditions the sensory and nutritional properties of cocoa beans could be improved. This study aimed to evaluate the effect of oscillating magnetic fields (OMF) on the kinetic growth of the core microbial communities of the Collections Castro Naranjal (CCN 51) cocoa bean. The data was obtained by three different models: Gompertz, Baranyi, and Logistic. The cocoa beans were subjected to different OMF strengths ranging from 0 mT to 80 mT for 1 h using the Helmholtz coil electromagnetic device. The viable microbial populations of lactic acid bacteria (LAB), acetic acid bacteria (AAB), and yeast (Y) were quantified using the colony-forming unit (CFU) counting method. The logistic model appropriately described the growth of LAB and Y under magnetic field exposure. Whereas the Baranyi model was suitable for describing AAB growth. The microbial populations in cocoa beans exposed to magnetic fields showed lower (maximum specific growth rate (µmax), values than untreated controls, with AAB exhibiting the highest average growth rate value at 5 mT and Y having the lowest average maximum growth rate value at 80 mT. The lower maximum specific growth rates and longer lag phases when exposed to magnetic fields compared to controls demonstrate the influence of magnetic fields on microbial growth kinetics.

Analysis of Mercury in Aquifers in Gold Mining Areas in the Ecuadorian Amazon and Its Associated Risk for Human Health.

Gold mining activity is a source of supply in many areas of the world, and especially in developing countries, it is practiced illegally and by applying unsafe techniques. Particularly in Ecuador, artisanal and small-scale gold mining (ASGM) is widespread, and it is based on the use of toxic substances, such as mercury (Hg), in gold recovery. Hg is a heavy metal that is water-insoluble, which, once mobilized, poses a threat to both the environment and human health. This study analyzes Hg concentrations in the six provinces of Napo, Sucumbíos, Orellana, Pastaza, Morona Santiago, and Zamora Chinchipe of the Ecuadorian Amazon region to conduct a human health risk assessment. Significant differences in Hg levels were found between provinces, but concentrations were below MPL imposed by Ecuadorian regulations everywhere. Nevertheless, a worrisome picture emerges, especially with regard to the most vulnerable receptors represented by the child population. There are multiple factors of incidence that may affect the possible future development of the phenomenon, and with reference to the social, economic, and environmental context of the region, it can be concluded that it may be appropriate to plan further investigation to arrive at a more comprehensive assessment. The results of this study can be used by decision makers to plan further investigation and to implement monitoring networks, risk mitigation strategies, and groundwater protection measures.

Intestinal Parasites in Populations of the Endemic Abyssinian Wattled Ibis (Bostrychia carunculata).

The wattled ibis (Bostrychia carunculata) is a little-known endemic Abyssinian species living in the Ethiopian and Eritrean Highlands. This bird species lives in close contact with humans in several parts of its range. Nothing is known about parasites infecting the wattled ibis and its distribution across populations, with the exception of some lice species. Here, we report the presence of eggs of several intestinal parasites (Trichostrongylus, Capillaria, and Ascaridia spp.) from feces of wild wattled ibises from three different locations: Addis Ababa, the Cheleklaka wetland surroundings, and Bale Goba, all in Ethiopia. These parasites might be transmitted from or to poultry, potentially reducing the production and survival of affected birds.

Fitorremediación con Brassicaceae y Apiaceae en suelos contaminados con metales pesados

Introducción: La cuenca media del río Bogotá viene sufriendo contaminación por metales pesados debido a los vertidos industriales. Esta fuente de agua ha sido utilizada para el riego de cultivos de ciclo corto, lo que ha provocado la contaminación por metales pesados de los suelos productivos. Objetivo: Evaluar un proceso de fitorremediación con las especies de Brócoli (Brassica oleracea var. italica Plenck) y Cilantro (Coriandrum sativum L.) en suelos contaminados con metales pesados en Mosquera, Colombia. Métodos: El muestreo se realizó con un diseño factorial al azar: a) proporciones de cilantro/brócoli (30 cilantro/70 brócoli, 50/50, 70 cilantro/30 brócoli y dos controles de tipo monocultivo de cada especie) y b) tiempo de fitorremediación (3, 6 y 9 meses), cada tratamiento con cuatro parcelas experimentales. El suelo y el tejido vegetal se analizó mediante espectrofotometría de absorción atómica para determinar la concentración de los metales pesados. Resultados: Las concentraciones de metales pesados en las muestras de tejido vegetal para brócoli y cilantro mostraron valores de Cd, Pb y Cr más altos que Hg y As, respecto al control. Las concentraciones de Cd, Pb y Cr presentaron valores significativamente más altos (P < 0.05) en suelos con cilantro y brócoli mezclados, respecto al sitio de control donde la concentración de Cd registró niveles significativamente más bajos que en los otros suelos. Las concentraciones de Cd, Pb y Cr fueron más altas en tejidos de cilantro y en suelos con cilantro en comparación con el control. Conclusiones: La fitorremediación por medio de las especies Brassica oleracea var. itálica Plenck y Coriandrum sativum L. en proporciones 70/30 o 30/70 a suelos con pH entre 5.5 y 6.0 permiten una buena recuperación de suelos con contenidos de metales pesados en términos de concentraciones altas a cortos plazos, iniciando la biorremediación a los tres meses y finalizando cargas de disponibilidad variable a los nueve meses.

Introduction: The middle basin of the Bogotá River has been suffering from heavy metal contamination due to industrial discharges. This water source has been used to irrigate short-cycle crops, which has resulted in heavy metal contamination of productive soils. Objective: To evaluate a phytoremediation process with the plant species Broccoli (Brassica oleracea var. Italica plenck) and Cilantro (Coriandrum sativum L.) in soils contaminated with heavy metals in Mosquera, Colombia. Methods: Sampling was performed with a randomized factorial design: a) cilantro/broccoli proportions (30 cilantro/70 broccoli, 50/50, 70 cilantro/30 broccoli and two monoculture type controls of each species) and b) phytoremediation time (3, 6 and 9 months), each treatment with four experimental plots. Soil and plant tissue were analyzed in the laboratory by atomic absorption spectrophotometry to determine the concentration of heavy metals. Results: The concentrations of heavy metals in plant tissue samples for broccoli and cilantro showed higher values of Cd, Pb and Cr than Hg and As, with respect to the control. The concentrations of Cd, Pb and Cr presented significantly higher values (P < 0.05) in soil where there was a mixed presence of cilantro and broccoli, with respect to the control site where the concentration of Cd registered significantly lower levels than in the other soils. Finally, Cd, Pb and Cr concentrations were higher in cilantro tissues and in soils with cilantro compared to the control. Conclusions: Phytoremediation by means of Brassica oleracea var. italica Plenck and Coriandrum sativum L. in 70/30 or 30/70 proportions in soils with pH between 5.5 and 6.0 allows a good recovery of soils with heavy metal contents in terms of high concentrations in short terms, starting bioremediation after three months and ending loads of variable availability after nine months.

Intracellular Zn(II) induced turn-on fluorescence of an L-phenylalanine-derived pseudopeptide.

A C2 symmetric L-phenylalanine-derived pseudopeptide has been synthesized for selective and sensitive recognition of Zn(II) ions in aqueous-organic media. The pseudopeptidic probes exhibit intracellular Zn(II) ion-sensing capabilities as demonstrated via live-cell fluorescence studies on RAW264.7 cells. Hence, we present a bioinspired pseudopeptide for potential biological applications involving intracellular Zn(II) ion detection.

Corrigendum to "Optimization of cacao beans fermentation by native species and electromagnetic fields" [Heliyon 9(4) April 2023 e15065].

[This corrects the article DOI: 10.1016/j.heliyon.2023.e15065.].

The key role of pretreatment for the one-step and multi-step conversions of European lignocellulosic materials into furan compounds.

Nowadays, an increased interest from the chemical industry towards the furanic compounds production, renewable molecules alternatives to fossil molecules, which can be transformed into a wide range of chemicals and biopolymers. These molecules are produced following hexose and pentose dehydration. In this context, lignocellulosic biomass, owing to its richness in carbohydrates, notably cellulose and hemicellulose, can be the starting material for monosaccharide supply to be converted into bio-based products. Nevertheless, processing biomass is essential to overcome the recalcitrance of biomass, cellulose crystallinity, and lignin crosslinked structure. The previous reports describe only the furanic compound production from monosaccharides, without considering the starting raw material from which they would be extracted, and without paying attention to raw material pretreatment for the furan production pathway, nor the mass balance of the whole process. Taking account of these shortcomings, this review focuses, firstly, on the conversion potential of different European abundant lignocellulosic matrices into 5-hydroxymethyl furfural and 2-furfural based on their chemical composition. The second line of discussion is focused on the many technological approaches reported so far for the conversion of feedstocks into furan intermediates for polymer technology but highlighting those adopting the minimum possible steps and with the lowest possible environmental impact. The focus of this review is to providing an updated discussion of the important issues relevant to bringing chemically furan derivatives into a market context within a green European context.

Experimental Prototype of Electromagnetic Emissions for Biotechnological Research: Monitoring Cocoa Bean Fermentation Parameters.

A Helmholtz-type electromagnetic emission device, which uses an oscillating magnetic field (OMF), with potential applications in biotechnological research, was built and validated. The coils were connected to an alternating current (AC) generator to generate a 0.5 to 110 mT field at their center. OMF measurements were performed with a Hall effect sensor with a digital signal connection (Arduino nano) and data output to a PC using LabVIEW v2017SP1 software. The fermentation process of the cocoa bean variety CCN 51, exposed to four levels of OMF density for 60 min (0, 5, 40, and 80 mT/60 min), was analyzed. Different variables of the grain fermentation process were evaluated over six days. The ANOVA test probed the device's linearity, accuracy, precision, repeatability, reliability, and robustness. Moreover, CCN 51 cocoa beans' EMF-exposure effect was evaluated under different OMF densities for 60 min. The results show the validity of the equipment under working conditions and the impact of EMF (electromagnetic fields) on the yield, deformation, and pH of cocoa beans. Thus, we concluded that the operation of the prototype is valid for use in biotechnological studies.

A 3D Bioprinted Gut Anaerobic Model for Studying Bacteria-Host Interactions.

The role of the human intestinal tract in host-microbe interactions has been highlighted in recent years. Several 3-dimensional (3D) models have been developed to reproduce the physiological characteristics of the human gut and to investigate the function of the gut microbiota. One challenge for 3D models is to recapitulate the low oxygen concentrations in the intestinal lumen. Moreover, most earlier 3D culture systems used a membrane to physically separate bacteria from the intestinal epithelium, which has sometimes made the studies of bacteria adhering to or invading cells less feasible. We report the establishment of a 3D gut epithelium model and cultured it at high cell viability under an anaerobic condition. We further cocultured intestinal bacteria including both commensal and pathogen directly with epithelial cells in the established 3D model under the anaerobic condition. We subsequently compared the gene expression differences of aerobic and anaerobic conditions for cell and bacterial growth via dual RNA sequencing. Our study provides a physiologically relevant 3D gut epithelium model that mimics the anaerobic condition in the intestinal lumen and supplies a powerful system for future in-depth gut-microbe interactional investigations.

Optimization of cacao beans fermentation by native species and electromagnetic fields.

Acid and bitter notes of the cocoa clone Cacao Castro Naranjal 51 (CCN 51) negatively affect the final quality of the chocolate. Thence, the fermentative process of cocoa beans using native species and electromagnetic fields (EMF) was carried out to evaluate the effect on the yield and quality of CCN 51 cocoa beans. The variables magnetic field density (D), exposure time (T), and inoculum concentration (IC) were optimized through response surface methodology to obtain two statistically validated second-order models, explaining 88.39% and 92.51% of the variability in the yield and quality of the beans, respectively. In the coordinate: 5 mT(D), 22.5 min (T), and 1.6% (CI), yield and bean quality improved to 110% and 120% above the control (without magnetic field). The metagenomic analysis showed that the changes in the microbial communities favored the aroma profile at low and intermediate field densities (5-42 mT) with high yields and floral, fruity, and nutty notes. Conversely, field densities (80 mT) were evaluated with low yields and undesirable notes of acidity and bitterness. The findings revealed that EMF effectively improves the yield and quality of CCN 51 cocoa beans with future applications in the development and quality of chocolate products.

An Adhesive Bioink toward Biofabrication under Wet Conditions.

Three-dimensional (3D) bioprinting is driving significant innovations in biomedicine over recent years. Under certain scenarios such as in intraoperative bioprinting, the bioinks used should exhibit not only cyto/biocompatibility but also adhesiveness in wet conditions. Herein, an adhesive bioink composed of gelatin methacryloyl, gelatin, methacrylated hyaluronic acid, and skin secretion of Andrias davidianus is designed. The bioink exhibits favorable cohesion to allow faithful extrusion bioprinting in wet conditions, while simultaneously showing good adhesion to a variety of surfaces of different chemical properties, possibly achieved through the diverse bonds presented in the bioink formulation. As such, this bioink is able to fabricate sophisticated planar and volumetric constructs using extrusion bioprinting, where the dexterity is further enhanced using ergonomic handheld bioprinters to realize in situ bioprinting. In vitro experiments reveal that cells maintain high viability; further in vivo studies demonstrate good integration and immediate injury sealing. The characteristics of the bioink indicate its potential widespread utility in extrusion bioprinting and will likely broaden the applications of bioprinting toward situations such as in situ dressing and minimally invasive tissue regeneration.

Recent advances in the remediation of perfluoroalkylated and polyfluoroalkylated contaminated sites.

Per- and polyfluoroalkyl substances (PFASs) are compounds used since 1940 in various formulations in the industrial and consumer sectors due to their high chemical and thermal stability. In recent years, PFASs have caused global concern due to their presence in different water and soil matrices, which threatens the environment and human health. These compounds have been reported to be linked to the development of serious human diseases, including but not limited to cancer. For this reason, PFASs have been considered as persistent organic compounds (COPs) and contaminants of emerging concern (CECs). Therefore, this work aims to present the advances in remediation of PFASs-contaminated soil and water by addressing the current literature. The performance and characteristics of each technique were addressed deeply in this work. The reviewed literature found that PFASs elimination studies in soil and water were carried out at a laboratory and pilot-scale in some cases. It was found that ball milling, chemical oxidation and thermal desorption are the most efficient techniques for the removal of PFASs in soils, however, phyto-microbial remediation is under study, which claims to be a promising technique. For the remediation of PFASs-contaminated water, the processes of electrocoagulation, membrane filtration, ozofractionation, catalysis, oxidation reactions - reduction, thermolysis and destructive treatments with plasma have presented the best results. It is noteworthy that hybrid treatments have also proved to be efficient techniques in the removal of these contaminants from soil and water matrices. Therefore, the improvisation and implication of existing techniques on a field-scale are greatly warranted to corroborate the yields obtained on a pilot- and laboratory-scale.

The Debye length and anionic transport properties of composite membranes based on supported ionic liquid-like phases (SILLPS).

An analysis of the ionic transport properties of BMIM [NTf2] in supported ionic-liquid-like phase (SILLP)-based membranes has been carried out based on experimental impedance spectroscopy measurements. The direct current (dc)-conductivity was analyzed to determine the temperature and frequency dependence. The fit of the loss tangent curve data with the Cole-Cole approximation of the electrode polarization model provides the conductivity, diffusivity, and density of charge carriers. Among these quantities, a significant increase in conductivity is observed when an ionic liquid is added to the polymeric matrix containing imidazolium fragments. The use of a recent generalization of Eyring's absolute rate theory allowed the elucidation of how the local entropy restrictions, due to the porosity of the polymeric matrix, control the conductive process. The fit of the conductivity data as a function of temperature manifests the behavior of the excess entropy with respect to the temperature. The activation entropy and enthalpy were also determined. Our results correlate the Debye length (LD) with the experimental values of conductivity, electrode polarization relaxation time, and sample relaxation time involved. Our work provides novel insights into the description of ionic transport in membranes as the diffusivity, mobility, and free charge density depend on the LD. Moreover, we discuss the behavior of the polarization relaxation time, the sample relaxation time, and the static permittivity as a function of the temperature.

Pseudopeptidic host adaptation in peptide recognition unveiled by ion mobility mass spectrometry.

Complexation of the glutamic-tyrosine-glutamic tripeptide (EYE) with a series of pseudopeptidic cages has been thoroughly investigated using different analytical techniques. The stoichiometry and affinities of the supramolecular host : guest complexes both in aqueous solution and in the gas-phase were obtained from a suitable combination of fluorescence spectroscopy, NMR, and mass spectrometry (MS) methods. The cages bearing basic groups (lysine, ornitine and histidine) display the tightest EYE binding in aqueous media following the order CyHis > CyLys > CyOrn, thus suggesting that Tyr side chain encapsulation is additionally modulated by the identity of the cage side chains and their ability to be engaged in polar interactions with the EYE peptide. Similarly, binding affinities estimated by MS methods clearly point towards a reduced affinity for the Cy cages with acidic pendant groups and a higher affinity of the CyHis cage over CyLys and CyOrn. Ion mobility spectrometry (IMS)-MS, assisted by molecular modelling, has been used to uncover the structural and conformational characteristics of the pseudopeptidic hosts and their supramolecular adducts with the EYE peptide. The cages display a collisional cross-section increase upon EYE inclusion that is associated with the expansion of the binding pocket of the cage cavity, thus constituting a unique example of conformational pseudopeptidic host adaptation to accommodate the inclusion of the guest.

An expanded whole-cell model of E. coli links cellular physiology with mechanisms of growth rate control.

Growth and environmental responses are essential for living organisms to survive and adapt to constantly changing environments. In order to simulate new conditions and capture dynamic responses to environmental shifts in a developing whole-cell model of E. coli, we incorporated additional regulation, including dynamics of the global regulator guanosine tetraphosphate (ppGpp), along with dynamics of amino acid biosynthesis and translation. With the model, we show that under perturbed ppGpp conditions, small molecule feedback inhibition pathways, in addition to regulation of expression, play a role in ppGpp regulation of growth. We also found that simulations with dysregulated amino acid synthesis pathways provide average amino acid concentration predictions that are comparable to experimental results but on the single-cell level, concentrations unexpectedly show regular fluctuations. Additionally, during both an upshift and downshift in nutrient availability, the simulated cell responds similarly with a transient increase in the mRNA:rRNA ratio. This additional simulation functionality should support a variety of new applications and expansions of the E. coli Whole-Cell Modeling Project.

Basically, nucleophilicity matters little: towards unravelling the supramolecular driving forces in enzyme-like CO2 conversion.

The reaction mechanism for the cycloaddition of CO2 to styrene oxide in the presence of macrocyclic pseudopeptides has been studied using DFT methods. Computational calculations indicate that the unprecedented catalytic behaviour previously observed experimentally, in which the most reactive species was not the most nucleophilic but the most basic one, can be associated to the tight cooperativity between several supramolecular interactions promoted by simple peptidomimetics able to display a synzymatic behaviour. This bizarre catalytic performance afforded remarkable conversions of a sluggish substrate like styrene oxide into the desired cyclic carbonate, even under relatively mild reaction conditions, opening the way for the practical use of CO2 as a raw material in the preparation of valuable chemicals. Furthermore, the remote modification of essential structural features of the macrocycle (synzyme engineering) permitted the driving forces of the synzymatic system to be analyzed, stressing the crucial synergic effect between an elegantly preorganized oxyanion hole and additional aromatic interactions.

Traditional Fermented Foods from Ecuador: A Review with a Focus on Microbial Diversity.

The development of early civilizations was greatly associated with populations' ability to exploit natural resources. The development of methods for food preservation was one of the pillars for the economy of early societies. In Ecuador, food fermentation significantly contributed to social advances and fermented foods were considered exclusive to the elite or for religious ceremonies. With the advancement of the scientific research on bioprocesses, together with the implementation of novel sequencing tools for the accurate identification of microorganisms, potential health benefits and the formation of flavor and aroma compounds in fermented foods are progressively being described. This review focuses on describing traditional fermented foods from Ecuador, including cacao and coffee as well as less popular fermented foods. It is important to provide new knowledge associated with nutritional and health benefits of the traditional fermented foods.