Pollution of freshwater ecosystems from polycyclic aromatic hydrocarbons (PAHs) is a global concern. The US Environmental Protection Agency (EPA) has included the PAHs pyrene, phenanthrene, and naphthalene among the 16 priority compounds of special concern for their toxicological effects. The aim of this study was to adapt and characterize a microbial consortium from ore waste with the potential to remove these three PAHs from water. This microbial consortium was exposed to the target PAHs at levels of 5, 10, 20, 50, and 100 mg L−1 for 14 days. PAH bioremoval was measured using the analytical technique of solid phase microextraction, followed by gas chromatography mass spectrometry (SPME-GC/MS). The results revealed that up to 90% of the target PAHs can be removed from water after 14 days at a concentration level of 100 mg L−1. The predominant group of microorganisms identified at the phylum taxonomic level were the Proteobacteria, while the Actinobacteria were the predominant subgroup. The removal of phenanthrene, naphthalene, and pyrene predominantly occurred in specimens of genera Stenotrophomonas, Williamsia, and Chitinophagaceae, respectively. This study demonstrates that the use of specific microorganisms is an alternative method of reducing PAH levels in water.

Our study shows that the molecular approach with 16S rDNA-DGGE identifies twofold more pathogenic bacteria than bacteriological culture, including complex bacterial communities associated with the development of bacterial sepsis in neonates. What is Known: • Neonatal sepsis affects 2.3% of birth in the NICU with a high mortality risk. • Evidence supports the use of molecular methods as an alternative to blood culture for identification of bacterial associated neonatal sepsis. What is New: • The DGGE gel is a good methodological approach for the identification of bacterial in neonatal blood samples. • This study describes the pattern of electrophoretic mobility obtained by DGGE gels and allows to determine the type of bacteria associated in the development of neonatal sepsis.

The amount of sargassum seaweed washed ashore on the beaches of Africa, Brazil, Central America and the Caribbean has increased to the point where it has become a social, environmental and financial issue. This research evaluates the potential for Sargassum spp. of the Mexican Caribbean coast to be used in the production of biomethane by estimating: a) stoichiometric methane production (SMP), b) biochemical methane potential (BMP) and c) biodegradability index (BI).The use of a sigmoidal model generalized to substrate to inoculum ratios is proposed, to predict the biomethane production during the anaerobic digestion (AD) of the sargassum. The information obtained shows the seaweed's potential for biomethane production and will be useful for estimates and scaling when implementing energy harnessing systems for sargassum in the Caribbean. The use of biomass is a key element in the move towards a circular economy. It is hoped that the use of technologies like AD leads to the integration of this seaweed into an economic value chain, thereby reducing the adverse effects of its presence on the ecosystem.

Phytoremediation is a feasible alternative to remediate soils polluted with toxic elements, which can be enhanced by manipulating plant-microbe interactions. Regarding this, free-living saprophytic fungi that interact beneficially with roots have been scarcely studied. Thus, the aim of this study was to assess the effect of a saprophytic fungus, Lewia sp., on the plant growth and the ability of Dodonaea viscosa to phytoaccumulate or phytostabilize soluble and insoluble sources of lead in a solid support. The growth of D. viscosa was influenced by both Pb and Lewia sp. While seedlings exposed to Pb showed a decrease in biomass production, in seedlings grown without Pb the biomass was stimulated by Lewia sp. The fungus strongly stimulated the weight-to-length ratio in roots. Regardless of the treatment, D. viscosa accumulated 4.4-6.5 times more Pb in roots than in shoots, conducting to low translocation factors (< 0.2). The presence of Lewia sp. significantly improved Pb accumulation, achieving high bioconcentration factors (> 22), which was attributed to an increased bioavailability and uptake of Pb due to the fungus. This study demonstrated that Lewia sp. could improve Pb-phytostabilization by D. viscosa in soils polluted with soluble and insoluble forms of Pb.

Water quality is relevant due to the complexity of the interaction of physicochemical and biological parameters. The Irrigation District 005 (ID005) is one of the most important agricultural region in Chihuahua, México; for that reason, it was proposed to investigate the water quality of the site. Water samples were collected in two periods: Summer (S1) and Fall (S2). The samples were taken from 65 wells in S1, and 54 wells in S2. Physicochemical parameters (PhP) such as Arsenic (As), Temperature, Electrical Conductivity (EC), Oxide Reduction Potential (ORP), Hardness, pH, Total Dissolved Solids (TDS), and Turbidity were analyzed. The data were subjected to statistical principal component analysis (PCA), cluster analysis (CA) and spatial variability tests. In both seasons, the TDS exceeded the Mexican maximum permissible level (MPL) (35% S1, 39% S2). Turbidity exceeded the MPL in S1 (29%) and in S2 (12%). Arsenic was above the MPL for water of agricultural use in 9% (S1) and 13% (S2) of the wells. The PCA results suggested that most variations in water quality in S1 were due to As, pH and Temperature, followed by EC, TDS and Hardness; while in S2 to EC, TDS and Hardness, followed by As and pH.

The availability of good quality water resources is essential to ensure healthy crops and livestock. The objective of this study was to evaluate the level of pollution in Bustillos Lagoon in northern Mexico. Physical-chemical parameters like sodium, chloride, sulfate, electrical conductivity, nitrates, and the pesticide dichlorodiphenyltrichloroethane (DDT) were analyzed to determine the water quality available in the lagoon. Although DDT has been banned in several countries, it is still used for agricultural purposes in Mexico and its presence in this area had not been analyzed previously. Bustillos Lagoon was divided into three zones for the evaluation: (1) industrial; (2) communal lands; and (3) agricultural. The highest concentrations of sodium (2360 mg/L) and SAR (41 meq/L) reported in the industrial zone are values exceeding the United Nations Food and Agricultural Organization (FAO) irrigation water quality guidelines. DDT and its metabolites were detected in all of the 21 sites analyzed, in the agricultural zone ∑DDTs = 2804 ng/mL, this level is much higher than those reported for other water bodies in Mexico and around the world where DDT has been used heavily. The water in the communal zone is the least contaminated, but can only be recommended for irrigation of plants with high stress tolerance and not for crops.

Polymeric-based composites can contribute to enhancing the detection, stability, and performance of enzymatic biosensors, due to their high structural stability, conductivity, and biocompatibility. This work presents the fabrication of a nanocomposite of polyaniline (PAni)/gold nanoparticles (AuNP)/carboxylated multiwalled carbon nanotubes (cMWCNT) as functional support for covalently linked catalase (CAT) enzyme. PAni was electropolymerized on a screen-printed carbon electrode (SPCE) and decorated with AuNP to improve charge transfer properties. CAT was bonded through amide formation using the carboxylic groups of cMWCNT, resulting in PAni/AuNP/cMWCNT/CAT biosensor. The structural and electroactive characteristics of the nanocomposite were studied by SEM, FT-IR, and cyclic voltammetry. The optimal performance was achieved after CAT immobilization over PAni/AuNP/cMWCNT/nanocomposite, showing improved analytical features such as a fast amperometric response of 1.28 s, a wide detection range from 0.01 to 6.8 mM, a correlation coefficient (R 2) of 0.9921, a low detection limit of 2.34 µM, and an average recovery rate of 99.6% when evaluated in milk samples. Additionally, the bioelectrode showed excellent selectivity and retained bioactivity after 30 days of storage. Such remarkable performance proved the synergistic effects of both the high surface area of the cMWCNT and AuNP and the inherent PAni electroactivity, yielding direct electron transfer from CAT.

Glutathione peroxidase 3 (GPx3) is the only extracellular selenoprotein (Sel) that enzymatically reduces H2O2 to H2O and O2. Two GPx3 (CqGPx3) cDNAs were characterized from crayfish Cherax quadricarinatus. The nerve cord CqGPx3a isoform encodes for a preprotein containing an N-terminal signal peptide of 32 amino acid residues, with the mature Sel region of 192 residues and a dispensable phosphorylation domain of 36 residues. In contrast, the pereiopods CqGPx3b codes for a precursor protein with 19 residues in the N-terminal signal peptide, then the mature 184 amino acid residues protein and finally a Pro-rich peptide of 42 residues. CqGPx3 are expressed in cerebral ganglia, pereiopods and nerve cord. CqGPx3a is expressed mainly in cerebral ganglia, antennulae and nerve cord, while CqGPx3b was detected mainly in pereiopods. CqGPx3a expression increases with high temperature and hypoxia; meanwhile, CqGPx3b is not affected. We report the presence and differential expression of GPx3 isoforms in crustacean tissues in normal conditions and under stress for high temperature and hypoxia. The two isoforms are tissue specific and condition specific, which could indicate an important role of CqGPx3a in the central nervous system and CqGPx3b in exposed tissues, both involved in different responses to environmental stressors.