Roberto Rico-Martínez

Autonomous University of Aguascalientes | UAA · Departamento de Química

The marine environment is an abundant source of organisms which are rich in functional/bioactive compounds. Many of these compounds exhibit a remarkable potential for medical, industrial and biotechnological applications. Handled appropriately, with a focus on sustainability, these organisms and compounds can offer new and renewable feedstocks for...

Wastewater Treatment Plants from industrial and municipal facilities are intended to remove diverse chemical and physical contaminants by using multistep processes. For a long time, research and development were focused on removal efficiency based on indicators like the chemical oxygen demand and the biochemical oxygen demand, among many others to...

The elemental composition of biological structures in ostracods cultured under standard conditions is a biological reference material and a baseline to study bioaccumulation due to exposure to inorganic compounds in laboratory experiments or samples collected from the environment in ostracods. Ostracods are used as paleoclimatic, and paleo-evolutio...

Organisms are usually exposed to mixtures of emerging pollutants in aquatic environments. Due to their widespread use and environmental relevance, the individual and combined effects of the drugs azithromycin (AZT) and ivermectin (IVM) on the freshwater rotifer Lecane papuana and the euryhaline rotifer Proales similis were investigated. Rotifers sh...

In this research, a hydraulic characterization of a 14 km segment of the San Pedro River, flowing through the center of the Aguascalientes Valley, was conducted. More than 50 years of flow measurement records were processed to obtain daily flows during dry and rainy seasons. Through geospatial analysis, areas with hydraulic retention, influenced by...

Background: While naturally occurring, heavy metals such as chromium, lead, and mercury also reach aquatic environments via anthropogenic activities, sometimes at alarming concentrations thereby altering the dynamics of the communities. Chromium, which is present in the discharge from automotive and tannery industries, occurs in two stable forms: t...

Data regarding the effects of binary metal mixtures in marine zooplankton are scarce, particularly for rotifers. We examined the toxicity of 21 binary equitoxic mixtures of As, Cd, Cu, Fe, Hg, Pb, and Zn on the euryhaline rotifer Proales similis. The toxic units (TU50) revealed that 20 of these binary mixtures exhibited synergistic effects (TU50 <...

The depletion of macronutrients, the increasing costs of producing nutrients and fertilizers, metal components, concerns about environmental effects, recycling trends in big companies, are among others significant factors boosting the need for obtaining resources from wastewater. New biological, chemical, and physical technologies allow the recycli...

Recovery of metals from wastewater is a reality in selected wastewater treatment plants worldwide. Several low-cost techniques have been already implemented in wastewater treatment plants in industry to recover specific metals. Adsorption, coagulation, flocculation, and precipitation techniques are relatively low-cost techniques already implemented...

Macronutrients like phosphorous (P) and Nitrogen (N) or nutrients like Calcium (Ca) and Potassium (K) could be recovered from wastewater. Recently, several technologies like enhanced biological phosphorous removal, chemical and electrical precipitation of nitrogen, microalgae-based methods to recover nitrogen, struvite transformed into fertilizer,...

An integral analysis of the acute and chronic toxicity, bioaccumulation, sites of entry, and distribution of four trace metals: copper, iron, lead, and nickel, and the non-trace metal mercury were performed in the ciliate Paramecium caudatum. Mercury was the fastest metal accumulated, and the most toxic. The sensitivity of Paramecium caudatum to th...

We evaluated the multi-and transgenerational effects of single and combined environmentally relevant concentrations of glyphosate (GLY) and chlorpyrifos (CPF) in the estuarine rotifer Proales similis. The acute and chronic toxicities of GLY and CPF were determined as individual compounds and as a mixture. Rotifers were exposed to environmental conc...

Interaction between rotifers species with Aeolosoma hemprichi is poorly understood. Also their feeding habits and biological interaction. Therefore, the present study had as a main goal to perform observations on the in vitro feeding behavior. The organisms were cultured with a photoperiod of 16h of light and 8h of darkness at a temperature of 25ºC...

Glyphosate affects several biochemical pathways and it has been reported to alter the energy allocation in aquatic invertebrates. Thus, this research was aimed to a) characterize in silico three glycolytic enzymes (hexokinase HK, phosphofructokinase PFK, and pyruvate kinase PK), and b) perform molecular docking of glyphosate and glycolytic enzymes....

This study aimed to characterize enzymes of the tricarboxylic acids pathway through in silico analysis and provide tools for further research related as potential biomarkers of energy (re)allocation. Putative sequences of amino acids were identified through tBLASTn in the genomes of B. asplanchnoidis, B. calyciflorus, B. koreanus, B. paranguensis,...

Chloroquine (CQ) has been widely used for many years against malaria and various viral diseases. Its important use and high potential to being persistent make it of particular concern for ecotoxicological studies. Here, we evaluated the toxicity of CQ alone and in combination with copper (Cu) to the euryhaline rotifer Proales similis. All experimen...

The unnecessary and irresponsible use of medicines by humans has polluted the environment (mainly water). Tons of active chemicals discharge into aquatic systems. Consequently, nontarget bacteria are exposed to low doses for long periods. Therefore, they acquire resistance and that resistance is transferred as drug-resistant genes. Undeveloped coun...

Antibiotics are emergent contaminants of great concern in recent times due to the indiscriminate use in public health, livestock and aquaculture for therapeutic purposes. Antibiotics contribute to the increase in chemical oxygen demand in wastewater plants. More worrisome is the development of antibiotic resistant genes (ARG) and antibiotic resista...

Glyphosate levels and the transfer of glyphosate across trophic levels have rarely been studied in zooplankton. The food preferences of zebrafish during the first-feeding stage (which is critical for the survival of organisms), were analyzed because of the requirement for live food. Larval survival begins to be affected when glyphosate intake excee...

Effectiveness of pyrethroid insecticides against pests including bark beetles (Dendroctonus spp.) is well known, but little is known about their (a) residuality and persistence in forests after application to control an outbreak and (b) ability to bioaccumulate in insects, which could cause adverse effects on the trophic chains. The 24 h lethal tox...

Pesticides are important tools to increase agriculture productivity and to deal with domestic pests. Once they were elevated to the category of relevant items brought by modernity. However, when Rachel Carson published her famous work “Silent Spring” humans worldwide were awakened to the problems caused by excessive and inappropriate use of these c...

Understanding how local conditions and dispersal dynamics structure communities of passively dispersing aquatic invertebrates remains uncertain, especially in aridland systems. In these systems, dispersal is irregular and successful colonization is subject to priority effects. To investigate these factors, we compared rotifer species composition fr...

The combined effects of two temperatures (20° and 25°C) and food densities (1 × 10 4 and 1 × 10 6 cells/mL) of three microalgae, Chlorella vulgaris, Nannochloropsis oculata and Scenedesmus obliquus on the life history of Euchlanis dilatata were evaluated. Our work integrated: effects of temperature on the activation energy (Ea), and evaluation of t...

Plankton is important for water reservoirs as they are essential for web chains and control populations of bacteria and organic particulates by their filter-feeding behavior. Generally, toxicity tests evaluate mortality or reproduction, however, comet assay has emerged as a useful tool to assess adverse effects on aquatic organisms such as genotoxi...

Chloroquine (CQ) has been widely used for many years against malaria and various viral diseases. Its important use and high potential to being persistent make it of particular concern for ecotoxicological studies. Here, we evaluated the toxicity of CQ alone and in combination with copper (Cu) to the euryhaline rotifer Proales similis . All experime...

The genus Lecane is highly diverse, there are 209 species, most of which inhabits tropical aquatic systems. In Quintana Roo 42 species have been reported, one of these is Lecane bulla described at the widest distribution throughout the Yucatan peninsula however; their morphotypes and demographic features are unknown. Therefore, the objective of thi...

Heavy metals are still a matter of concern as they might reach aquatic environments due to anthropogenic activities like metal-mechanic or mining, which are part of the main economic activities in different regions around the world. The exposure to chromium may be linked to discharges from automotive and tannery industries, representing a threat to...

Application of pyrethroid pesticides and semiochemicals are two treatments used worldwide to control conifer bark beetles (Dendroctonus spp.); their residues can reach water reservoirs and water currents through run off and affect non-target organisms such as freshwater invertebrates. Therefore, we assessed the 48-h lethal toxicity, chronic toxicit...

Desert aquatic systems are widely separated, lack hydrologic connections, and are subject to drought. However, they provide unique settings to investigate distributional patterns of micrometazoans, including rotifers. Thus, to understand rotifer biodiversity we sampled 236 sites across an array of habitats including rock pools, springs, tanks, flow...

Metals are widely used in modern society harming the environment; their toxicity cause environmental adverse effects to many organisms including zooplankton. This contribution employed: (a) acute and chronic toxicity tests, (b) epifluorescence image analysis, and (c) atomic absorption techniques, to analyze toxicity of four trace (copper, iron, nic...

We have determined lead concentration of water, sediment, and zooplankton samples of El Niá gara, a reservoir in Aguascalientes, Mexico. Our results include the first report of bioconcentration factor (BCF) obtained in an actual ecosystem (as opposed to the experimental setups in the laboratory) for a rotifer species; Asplanchna brigthwellii (BCF c...

The Brachionus plicatilis complex represents the most studied group of rotifers, although the systematics of the species complex has not been completely clarified. Many studies have been conducted trying to explore the diversity within the complex, leading to the recognition of three major morphotypes: large (L), small-medium (SM), and small (SS)....

Antecedentes: El diclofenaco (DCF) es un antiinflamatorio no esteroideo (AINE) que ha sido encontrado en aguas superficiales y subterráneas, derivado de su consumo en salud humana y veterinaria. Además, ha sido estudiado en diferentes modelos animales dulciacuícolas y se ha demostrado que tiene efectos perjudiciales en cladóceros, peces y anfibios,...

We detected arsenic near the Tolimique Dam, an archaeological ecotourism area in Aguascalientes, México. Fortunately, the concentration range of this metalloid (0.001 to 0.003 mg L⁻¹) did not exceed the total arsenic in water allowed by NOM-127-SSA1-1994 (0.025 mg L⁻¹). However, because arsenic is a high-risk priority pollutant at low concentration...

Following a quantitative analysis of adequate feedstock, comprising 11 woody biomass species, four biochars were generated using a Kon-Tiki flame curtain kiln in the state of Aguascalientes, Mexico. Despite the high quality (certified by European Biochar Certificate), the biochars contain substantial quantities of hazardous substances, such as poly...

Although chydorids are the most diverse cladocerans in the world, there is still little information available related to their biology and even less with respect to their susceptibility to toxicants. Therefore, this work aimed to implement protocols with Alona guttata for acute, chronic, and sublethal toxicity tests, using the environmental concern...

This study used freshwater rotifers to evaluate the effects of two endocrine disrupting compounds (EDCs), luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which can be considered emergent contaminants in urban and rural wastewater and are of ecotoxicological importance. LH stimulates the synthesis of testosterone, whereas FSH promot...

A comparison of acute toxicity (LC50 values) among nine toxicants: a) six metals: Cd, Cr, Cu, Hg, Pb, Ti, and b) three organics: benzene, ethyl acetate, and toluene, between the exotic cladoceran species Daphnia magna Straus 1820 and two native strains of freshwater cladoceran species: Daphnia pulex Leydig, 1860 and Simocephalus vetulus (O. F. Müll...

We studied the accumulation of lead as Pb(NO3)2 in the freshwater rotifer Lecane quadridentata using Leadmium Green and x-ray microanalysis by energy dispersion. The results indicate that lead is bioaccumulated in great amounts in the stomach after the rotifer is exposed for 24 h to 0.5 mg L⁻¹ of Pb(NO3)2. When the exposure concentration of Pb(NO3)...

In Aguascalientes, Mexico, there is a special concern about pesticides because of their intensive use on guava production areas, which are located in the vicinity of water reservoirs; thus, non-target organisms could be exposed. Thereafter, the aim of this work was to assess the effect of cypermethrin, Faena® (glyphosate), and malathion, which are...

Rotifera is a group of pseudocoelomate aquatic invertebrates with great potential as model organisms for ecotoxicology and genotoxicology. This potential is based on their: (a) fast growth and reproduction, (b) ease of culture and maintenance, (c) cyst production, (d) alternation of asexual and sexual generations, among others. While the use of rot...

The Rotifera is a group of pseudocoelomate aquatic invertebrates with a great potential as model organisms for ecotoxicology and genotoxicology. This potential is based its ability for: a) fast growth and reproduction, b) ease of culture and maintenance, c) cyst production, d) alternation of asexual and sexual generations, among others. While the u...

Antecedentes: Los parámetros fisicoquímicos y pruebas de toxicidad aguda sirven para valorar las condiciones del agua de los efluentes de las plantas de tratamiento de aguas residuales de acuerdo con la normativa de la NOM-003-SEMARNAT-1997. Objetivos: Conocer la calidad del agua del influente y efluente de la planta tratadora de aguas residuales...

Variation in thermal tolerance among related species plays an important role in establishing their range and distribution. We conducted life table experiments with three rotifer species of the Lecane genus at three temperatures (20, 25 and 30°C). The rotifers were fed on Nannochloropsis oculata at 106 cells.mL−1 to test the hypothesis that Lecane p...

We provide descriptions of the sexual reproductive biology of 12 species of rotifers from seven families and seven genera: Brachionus angularis, B. araceliae, B. ibericus, B. quadridentatus (Brachionidae); Cephalodella catellina (Notommatidae); Collotheca ornata (Collothecidae); Epiphanes brachionus (Epiphanidae), Filinia novaezealandiae (Trochosph...

Latin America and the Caribbean are the regions with the greatest biological diversity on earth, and endemism in these regions is very high. Regarding freshwater ecosystems and water availability, Latin America and the Caribbean hold more than 30% of earth's available freshwater resources, but this water is very unequally distributed and at risk. M...

Bioaccumulation of trivalent (CrIII) and hexavalent chromium (CrVI), and its adverse effects were studied in two rotifer species: Brachionus calyciflorus (two different strains), and Lecane quadridentata. Median Lethal Concentration (LC50) at 24 h of both species showed that CrVI is highly toxic: LC50 ranges from 4.7 × 10−5 to 4 × 10−6 mg L−1), com...

An important objective of aquatic ecotoxicology is to determine the effects of toxic compounds in organisms that play a central role in aquatic communities where rotifers have a large impact on several important ecological processes. The contribution of the rotifers to secondary production in many aquatic communities is substantial as they are ofte...

Nanostructured materials (NSMs) of silver (Ag@TiO 2 ) and copper (TiO 2 -Cu 2+ ) doped titanium dioxide were synthesized, fully characterized, and evaluated for their antimicrobial efficiency and effects on Arabidopsis thaliana . The NSMs were prepared using an environmentally benign route. The physicochemical properties of the materials were deter...

A description of the research I conducted at the Georgia Institute of Technology regarding the laboratoty analysis of the toxicity of Macondo oil and Corexit9500.

We determine toxicity of five metals (Al, Cd, Pb, Fe and Zn) by acute and chronic toxicity tests using species representative of three freshwater trophic levels: a) the predatory rotifer Asplanchna brightwellii, b) three primary consumers: Brachionus calyciflorus, Daphnia magna, and Daphnia cf. prolata (D. pulex complex), c) two primary producers:...

The Tula River watershed is a water flow system that runs from the State of Mexico to the south-central part of Hidalgo State in Mexico that includes the Mezquital Valley which was originally a semiarid zone and now is an important agricultural region. We studied the River Tula watershed regarding biological, chemical, and physical parameters, desc...

The organophosphate and carbamate pesticides methyl-parathion and carbaryl have a common action mechanism: they inhibit acetylcholinesterase enzyme by blocking the transmission of nerve impulses. However, they can alter the expression of exocytotic membrane proteins (SNARE), by modifying release of neurotransmitters and other substances. This study...

Vinclozolin (VZ) is a dicarboximide fungicide widely used on fruits, vegetables and wines, effective against fungi plagues. In this study we characterized the effects of VZ using a 4-day reproductive chronic assay with the freshwater rotifer Brachionus calyciflorus. The assay included observations of several features of asexual and sexual reproduct...

Objective: To identify the presence of joint muscular and cholinergic systems in two freshwater rotifer species: Brachionus calyciflorus and Lecane quadridentata. Methods: Staining the muscle actin fibers with phalloidin-linked fluorescent dye, and acetylcholine with Amplex Red Acetylcholine/Acetylcholinesterase Assay Kit, and then using Confocal L...

The study of sexual reproductive behavior supported by ultrastructural evidence is important in rotifers to describe differences among potential cryptic species. In this research, the morphology of the rotifer Brachionus bidentatus is described at the ultrastructural level, using electronic microscopy, together with a brief description and discussi...

The study of sexual reproductive behavior supported by ultrastructural evidence is important in rotifers to describe differences among potential cryptic species. In this research, the morphology of the rotifer Brachionus bidentatus is described at the ultrastructural level, using electronic microscopy, together with a brief description and discussi...

In many aquatic invertebrates including monogonont rotifers, sex provides genetic variation and dormant stages that allows dispersal in time and space. While the reproductive biology of some solitary monogonont rotifer species is known, little is known concerning mating behaviors in colonial rotifers. Coloniality poses unique challenges to the typi...

Ph.D. Terry W. Snell

Acute toxicity tests of five metals (aluminum, cadmium, iron, lead, zinc) were performed to determine LC50 values in two species of freshwater rotifers: Asplanchna brigthwellii and its prey Brachionus calyciflorus. We conducted the tests using neonates less than 24 hr-old, each test consisted of five replicates, negative control and five metal conc...

Acute toxicity tests of five metals (aluminum, cadmium, iron, lead, zinc) were performed to determine LC50 values in two species of freshwater rotifers: Asplanchna brigthwellii and its prey Brachionus calyciflorus. We conducted the tests using neonates less than 24 hr-old, each test consisted of five replicates, negative control and five metal conc...

Using the marine rotifer Brachionus plicatilis acute toxicity tests, we estimated the toxicity of Corexit 9500A�, propylene glycol, and Macondo oil. Ratios of 1:10, 1:50 and 1:130 for Corexit 9500A�:Macondo oil mixture represent: maximum exposure concentrations, recommended ratios for deploying Corexit (1:10e1:50), 1:130 the actual dispersant:oil r...

Marked contributions to the field of ecotoxicology provided by studies conducted with rotifers are reported herein. Emphasis is placed on the acute sensitivity of rotifers to three groups of toxicants: metals, organic compounds, and pesticides. The main characteristics of Rotifera, species used for ecotoxicological studies, endpoints, and various o...

Relative contributions of water- and methanol-soluble compounds and their hydrophobic/hydrophilic subfractions to the ROS (reactive oxygen species)-generating potential of ambient fine aerosols (D(p) < 2.5 μm) are assessed. ROS-generating (or oxidative) potential of the particulate matter (PM) was measured by the dithiothreitol (DTT) assay. Particl...

Toxicity tests were performed on the freshwater rotifer Lecane quadridentata exposed to the pesticides carbaryl and methyl parathion (lethal, sublethal, and chronic) to compare the sensitivity between different endpoints: (a) 48-h mortality; (b) 30-min in vivo inhibition of esterase activity; (c) 5-day inhibition of the instantaneous growth rate. T...