RESUMEN

The Gulf of Mexico (GoM) is exposed to a diversity of contaminants, such as hydrocarbons and heavy metal(oid)s, either from natural sources or as a result of uncontrolled coastal urbanisation and industrialisation. To determine the effect of these contaminants on the marine biota along the Mexican GoM, the biological responses of the shoal flounder Syacium gunteri, naturally exposed, were studied. The study area included all the Mexican GoM, which was divided into three areas: West-southwest (WSW), South-southwest (SSW) and South-southeast (SSE). The biological responses included the global DNA methylation levels, the expression of biomarker genes related to contaminants (cytochrome P450 1A, glutathione S-transferase, glutathione reductase, glutathione peroxidase, catalase, and vitellogenin), histopathological lesions and PAH metabolites in bile (hydroxynaphthalene, hydroxyphenanthrene, hydroxypyrene and Benzo[a]pyrene). The correlation between the biological responses and the concentration of contaminants (hydrocarbons and metal(oid)s), present in both sediments and organisms, were studied. The shoal flounders in WSW and SSW areas presented higher DNA hypomethylation, less antioxidative response and biotransformation gene expression and a higher concentration of PAH metabolites in bile than SSE area; those responses were associated with total hydrocarbons and metals such as chromium (Cr). SSE biological responses were mainly associated with the presence of metals, such as cadmium (Cd) and copper (Cu), in the tissue of shoal flounders. The results obtained on the physiological response of the shoal flounder can be used as part of a permanent active environmental surveillance program to watch the ecosystem health of the Mexican GoM.

Asunto(s)

Lenguado/fisiología , Contaminantes Químicos del Agua/toxicidad , Animales , Biomarcadores , Ecosistema , Monitoreo del Ambiente , Golfo de México , Hidrocarburos Policíclicos Aromáticos/toxicidad

RESUMEN

Isostichopus badionotus is a sea cucumber species of great ecological and economic relevance for Mexico and Central American and Caribbean countries; however, the protocols for the extraction of the nucleic acids have not yet been published. In this study, we describe the first protocols to obtain DNA and RNA from different tissues of I. badionotus, which include the respiratory tree, gonad, longitudinal muscle bands, anterior intestine and cloaca. The extraction of high-quality DNA was performed using the DNeasy Blood & Tissue kit (Qiagen, Valencia, CA, USA) with minor modifications in different points of the protocol. Concerning the RNA, the method of TRIzol was used. This method is particularly advantageous in situations where cells or tissues are enriched for endogenous RNases or when the separation of cytoplasmic RNA from nuclear RNA is impractical. The methodologies used in this study allowed us to obtain DNA and RNA of high quality and integrity in the different tissues of I. badionotus, which will be the basis for future genomic and transcriptomic studies. •The successful extraction of DNA and RNA was achieved in the different tissues of I. badionotus.•The concentrations of DNA and RNA obtained were adequate for a diversity of analyses at a molecular level.

RESUMEN

BACKGROUND: We assessed metrics of the metazoan parasite infracommunities of the dusky flounder (Syacium papillosum) as indicators of aquatic environmental health of the Yucatan Shelf (YS) prior to oil extraction. We sampled the dusky flounder and its parasites along the YS, mostly during the 2015 north wind season (November-April). Our aims were: (i) to determine whether the parasite infracommunity metrics of S. papillosum exhibit significant differences among YS subregions; (ii) to determine whether the probability of the occurrence of its parasite species and individuals were affected by environmental variables, nutrients, heavy metals and hydrocarbons at the seascape level; and (iii) to determine whether there were statistical differences between the parasite infracommunity metrics of S. papillosum from YS and those of Syacium gunteri from the Campeche Sound. Multivariate statistical analyses and generalised additive models (GAMs) were used to examine the potential statistical associations between the contaminants, environmental variables and parasite community metrics, and the maximum entropy algorithm (MaxEnt) was used to characterise the habitat's suitability for the parasite's probability of occurrence. RESULTS: We recovered 48 metazoan parasite species from 127 S. papillosum, with larval cestodes and digeneans being the most numerically-dominant. Multivariate analyses showed significant differences in parasite infracommunity metrics among Western YS, Mid YS and Caribbean subregions, with the latter being the richest in species but not in individuals. The GAM and MaxEnt results indicated a negative effect of top predators (e.g. sharks and rays) removal on parasite metrics. The parasite infracommunities of S. papillosum were twice as rich in the number of species and individuals as those reported for S. gunteri from the Campeche Sound. CONCLUSIONS: The significant differences among subregions in parasite metrics were apparently due to the interruption of the Yucatan current during the north wind season. The fishing of top predators in combination with an influx of nutrients and hydrocarbons in low concentrations coincides with an increase in larval cestodes and digeneans in S. papillosum. The dusky flounder inhabits a region (YS) with a larger number of metazoan parasite species compared with those available for S. gunteri in the Campeche Sound, suggesting better environmental conditions for transmission in the YS.

Asunto(s)

Biomarcadores Ambientales , Enfermedades de los Peces/parasitología , Lenguado/parasitología , Parásitos/aislamiento & purificación , Animales , Biota , Enfermedades de los Peces/epidemiología , México/epidemiología , Análisis Multivariante , Parásitos/clasificación

RESUMEN

Benzo(a)pyrene (BaP), the prototype of polycyclic aromatic hydrocarbons, is known to exhibits genotoxic and carcinogenic effects promoting molecular impacts. The dataset presented here is associated with the research article paper entitled "Transcriptome Analysis Reveals Novel Insights Into the Response of Low-dose Benzo(a)pyrene Exposure in Male Tilapia". In this article, we presented a transcriptomic characterization of male tilapia exposure to BaP in the short term. This data provides an extended analysis of changes in the gene expression and identification of pathways in the liver and testis of male tilapia exposure to BaP. We used gene set enrichment analysis (GSEA) and sub-network enrichment analysis (SNEA) to identify gene networks and pathways associated with molecular adverse effects of BaP exposure. The data indicates that target pathways related to promoting carcinogenesis such as DNA repair and DNA replication were affected as well as other crucial biological processes. Moreover, to determine whether some of the key reported genes of DNA damage are affected by BaP exposure, Quantitative PCR (qPCR) was performed. Gene set categories and sub-networks are provided and the corresponding signature differences from BaP exposure are listed. The information in these datasets may contribute to understanding the potential carcinogenesis mechanism of action from low BaP exposure.

RESUMEN

Salvinia minima was assessed for its ability to accumulate lead (Pb) by exposing it to concentrations of 40µM Pb(NO3)2 during 24h. At the same time, the expression levels were quantified, of four genes coding for transporters: SmABCC (ABCC-MRP), SmATPase (ATPase-P3A), SmNhaD (Type-Na+/H+) and SmABCG (ABCG-WBC). In the absence of lead, S. minima had very low expression of those genes, when plants were exposed to the metal however, those genes showed a rapid (in just three hours or less) and sharp increase (up to 60 times) in their expression, particularly the SmNhaD (Type-Na+/H+) gene. This sharp increase in expression levels of the genes studied, occurred at the same time that the plant accumulated the highest content of lead in its tissues. The first two genes, are apparently implicated in detoxification and lead accumulation mechanisms, while the other two genes are apparently involved in maintaining cell balance (homeostatic control) and membrane integrity. Our results confirmed that S. minima is efficient for phytoremediation of water bodies contaminated by lead, as it is efficient in accumulating this metal in its tissues (bioconcentration factor; BCF) values greater than 1000, in short times of exposure. More importantly, our data on the expression profiles of four genes coding for transporters, represent a first sight scenario of the molecular basis for understanding the different mechanism of detoxification, apparently present in this aquatic fern.

Asunto(s)

Helechos/genética , Plomo/toxicidad , Proteínas de Transporte de Membrana/genética , Proteínas de Plantas/genética , Contaminantes Químicos del Agua/toxicidad , Biodegradación Ambiental , Helechos/efectos de los fármacos , Helechos/metabolismo , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Plomo/metabolismo , Proteínas de Transporte de Membrana/metabolismo , Proteínas de Plantas/metabolismo , Contaminantes Químicos del Agua/metabolismo

RESUMEN

The present study reports partial sequences of a group of genes used as exposure and effect biomarkers of organic contaminants and/or heavy metals in Syacium gunteri. In order to isolate these sequences, cDNA was used to amplify fragments between 200 and 800 bp, which were then cloned and sequenced. The sequences presented high percentages of identity with genes involved in the metabolism of xenobiotic biotransformation (cytochrome P4501A and glutathione S-transferase), oxidative stress (catalase, glutathione reductase, glutathione peroxidase and superoxide dismutase), reproductive system (vitellogenin) and with the tumor suppressor protein p53 reported in the GenBank database. Subsequently, from the deduced sequence of amino acids of each fragment, their tridimensional structure was predicted, using homologous proteins from the Protein Data Base. This study generates an important base of molecular biomarkers for the monitoring of environmental health in the Gulf of Mexico.

Asunto(s)

Peces Planos/genética , Metales Pesados/análisis , Estrés Oxidativo/genética , Animales , Biomarcadores/metabolismo , Catalasa/metabolismo , Glutatión Peroxidasa/metabolismo , Glutatión Reductasa/metabolismo , Glutatión Transferasa/metabolismo , Golfo de México , ARN Mensajero/metabolismo , Superóxido Dismutasa/metabolismo , Proteína p53 Supresora de Tumor/genética

RESUMEN

Red drum (Sciaenops ocellatus) is a euryhaline fish commonly found in the Gulf of Mexico and along the Atlantic coast of North America. Because of high commercial demand and its euryhaline characteristics, aquaculture of this species has diversified from marine to low-salinity aquaculture systems. In recent years, interest in the feasibility of producing red drum in inland freshwater systems has grown and this prompted us to investigate its osmoregulatory capacity after rearing for 8 months in a freshwater aquaculture system. We compared the activities of several genes and enzymes involved in the osmoregulatory process in freshwater-acclimatized (FW) and seawater (SW) red drum. The gene expression profiles were variable: the expression of genes encoding Na+/K+-ATPase (NKA) and the cystic fibrosis transmembrane regulator (CFTR) was slightly higher in SW than FW fish, while phosphoenolpyruvate carboxykinase (PEPCK) and the glucocorticoid receptor messenger RNA (mRNA) levels were higher in FW red drum. The total plasma K concentration was 60.3% lower, and gill NKA activity was 63.5% lower in FW than in SW fish. PEPCK activity was twofold higher in FW than in SW red drum. Similarly, liver glycogen was 60% higher in FW fish. In summary, both gene expression and the enzyme activity data support the phenotypic plasticity of red drum and suggest that the limited capacity for ion homeostasis observed, in particular the low plasma K concentration, was due to the composition of freshwater and does not necessarily reflect a physiological inability to osmoregulate.

Asunto(s)

Peces/fisiología , Agua Dulce , Regulación de la Expresión Génica/fisiología , Aclimatación/fisiología , Animales , Organismos Acuáticos , Branquias/metabolismo , Osmorregulación , ARN Mensajero/metabolismo , Salinidad , Agua de Mar , ATPasa Intercambiadora de Sodio-Potasio/genética , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Equilibrio Hidroelectrolítico/fisiología

RESUMEN

The effects of copper toxicity on the photosynthetic activities of Avicennia germinans was investigated using two CuSO4 concentrations (0.062 and 0.33 M) added in Hoagland's solution in an aerated hydroponic system. Photosynthesis and chlorophyll fluorescence were measured after 30 h of copper stress. Results obtained in this study show that increasing levels of Cu(+2) of 0.062 and 0.33 M Cu(+2) resulted in a general reduction of the stomatal conductance (28 and 18%, respectively) and 100% of inhibition of net photosynthesis. Additionally, at these concentrations of Cu(+2), reductions of chlorophyll fluorescence parameters were also observed. These changes suggested that the photosynthetic apparatus of Avicennia germinans was the primary target of the Cu(+2) action. It is concluded that Cu(+2) ions causes a drastic decline in photosynthetic gas exchange and Chlorophyll fluorescence parameters in A. germinans leaves.

Asunto(s)

Avicennia/efectos de los fármacos , Clorofila/metabolismo , Cobre/toxicidad , Fotosíntesis/efectos de los fármacos , Estrés Fisiológico/efectos de los fármacos , Fluorescencia

RESUMEN

Aquatic hypoxia is a seasonal condition in some coastal and continental wetlands where co-exposure with polycyclic aromatic hydrocarbons (PAHs) pollution may be detrimental to the biota. In the present study, adult tilapia, an euryoxic fish of high economic importance, were intraperitoneally injected with benzo[a]pyrene (BaP) (20 mg kg(-1)) and then exposed to graded hypoxia to assess combined effects on some detoxification and fitness parameters. Seventy-two hours after a stepped decrease in dissolved oxygen (<2 mg L(-1)), BaP treatment resulted in a significant diminution on the biliary BaP concentration (70% of normoxic group) and an increase in blood glucose levels (2.17-fold compared with normoxic group). These effects returned to control values in the following 48 h of hypoxia exposure. BaP-induced CYP1A mRNA levels were unaffected by hypoxia, suggesting that reduced bile BaP concentration may be related with effects on protein amount or enzyme activities. LDH mRNA levels, blood lactate and hematocrit remained without change, suggesting no extreme detrimental effects for tilapia in the short-term of the BaP-hypoxia challenge. Our results indicate that BaP treatment and hypoxia targeted glucose metabolism and biliary BaP elimination, probably by favoring the storage of BaP in tilapia tissues.

Asunto(s)

Benzo(a)pireno/toxicidad , Bilis/química , Citocromo P-450 CYP1A1/metabolismo , Hígado/efectos de los fármacos , Tilapia/metabolismo , Contaminantes Químicos del Agua/toxicidad , Animales , Benzo(a)pireno/química , Glucemia/análisis , Citocromo P-450 CYP1A1/genética , Hematócrito , Hipoxia , L-Lactato Deshidrogenasa/genética , L-Lactato Deshidrogenasa/metabolismo , Ácido Láctico/sangre , Hígado/metabolismo , ARN Mensajero/metabolismo , Factores de Tiempo , Contaminantes Químicos del Agua/química

RESUMEN

AKR1A1 or aldehyde reductase is a member of the aldo-keto reductases superfamily that is evolutionarily conserved among species. AKR1A1 is one of the five AKRs (AKR1A1 and 1C1-1C4) implicated in the metabolic benzo(a)pyrene (BaP) activation to reactive BaP 7,8-dione. BaP is a polycyclic aromatic hydrocarbon (PAH) widely distributed in aquatic ecosystems and its metabolic activation is necessary to produce its toxic effects. Although the presence of AKR1A1 in fish has been reported, its tissue distribution in tilapia (Oreochromis niloticus) and AKR1A1 inducibility by BaP are not known yet. Moreover, cytochrome P4501A (CYP1A) mRNA expression in fish has been used as a PAH biomarker of effect. Therefore, BaP effects on AKR1A1 and CYP1A gene expressions in tilapia, a species of commercial interest, were investigated by real-time RT-PCR. A partial AKR1A1 cDNA was identified, sequenced and compared with AKR1A1 reported sequences in the GenBank DNA database. Constitutive AKR1A1 mRNA expression was detected mainly in liver, similarly to that of CYP1A. BaP exposure resulted in statistically significant AKR1A1 and CYP1A mRNA induction in liver (20- and 120-fold, respectively) at 24 h. On the other hand, ethoxyquin (EQ) was used as control inducer for AKR1A1 mRNA. Interestingly, EQ also induced CYP1A mRNA levels in tilapia liver. Our results suggest that teleost AKR1A1, in addition to CYP1A, are inducible by BaP. The mechanism of AKR1A1 induction by BaP and its role in fish susceptibility to BaP toxic effects remains to be elucidated.

Asunto(s)

Aldehído Reductasa/genética , Benzo(a)pireno/toxicidad , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Hígado/efectos de los fármacos , ARN Mensajero/genética , Animales , Secuencia de Bases , Cartilla de ADN , ADN Complementario , Hígado/enzimología , Masculino , Reacción en Cadena en Tiempo Real de la Polimerasa , Homología de Secuencia de Ácido Nucleico , Tilapia

RESUMEN

We determined the hepatic Cytochrome P4501A (CYP1A) mRNA and Ethoxyresorufin-O-deethylase (EROD) activities in the fish, Ariopsis felis, from highly polluted to relatively pristine regions in the southwest Gulf of Mexico and their relationship with the genetic polymorphisms of the same fish. We hypothesized that a high genetic variation reflects interindividual variability in levels of CYP1A mRNA underlying the pathway culminating in EROD induction caused by the environmental contaminants. Catfish from Laguna de Mecoacan exhibited marked induction of CYP1A mRNA and high levels of hepatic EROD activities, whereas fish from Laguna de Celestun showed no induction of CYP1A mRNA and moderately low levels of EROD activities. In contrast, the similarity index considering all samples varied from 0.4 to 0.87, showing a wide range of variation. A dendrogram showed a clear grouping of fish collected from the Laguna de Terminos, Rio Coatzacoalcos and Laguna de Celestun, with discrete subgroups according to region. In contrast, fish from Laguna de Mecoacan were grouped together completely separate from the rest of the fish. Despite the low number of fish from Mecoacan (a high bootstrap support was observed in this group), the results indicated a significant genetic variability in comparison with the other ecosystems included. The differential level of expression of CYP1A and the EROD activity observed among the ecosystems analyzed could be due to the high range of genetic variation, with special emphasis on fish collected in Mecoacan where it is possible to find a subspecies of Ariopsis felis.

Asunto(s)

Bagres/genética , Citocromo P-450 CYP1A1/genética , Regulación Enzimológica de la Expresión Génica , Hígado/enzimología , Polimorfismo de Longitud del Fragmento de Restricción , Análisis del Polimorfismo de Longitud de Fragmentos Amplificados/métodos , Animales , Bagres/metabolismo , Citocromo P-450 CYP1A1/biosíntesis , Exposición a Riesgos Ambientales , Monitoreo del Ambiente , Inducción Enzimática/efectos de los fármacos , Expresión Génica , ARN Mensajero/metabolismo , Especificidad de la Especie , Contaminantes Químicos del Agua/toxicidad

RESUMEN

The effect of heavy metal stress on the cell viability and leakage of electrolytes of Avicennia germinans leaf discs was investigated by the tissue tolerance test. Foliar discs were incubated with different Cd2+ or CU2+ concentrations for 24 h; thereafter, the cell membrane stability of the tissue was assayed by the cell viability Evans blue and leakage electrolytes methods. The results indicated that electrolyte leakage of the leaf discs increased 24 h after exposure to heavy metal stress, as shown by a reduction of the cell viability by 30% in discs exposed to higher doses of Cd2+ (0.546 M) and Cu2+ (0.7 M), respectively. Additionally, the histological analysis of the leaf discs exposed to heavy metal stress revealed that at higher Cd2+ and/or Cu2+ concentrations an increase in the intercellular spaces and destruction of mesophyll cells was observed 24 h after exposure. In summary, the biochemical and structural changes observed in foliar tissues of A. germinans suggest that higher cadmium and copper concentrations may result in structural changes and altered physiological characters in leaves.

Asunto(s)

Avicennia/citología , Supervivencia Celular/efectos de los fármacos , Electrólitos/metabolismo , Metales Pesados/farmacología , Avicennia/efectos de los fármacos , Avicennia/metabolismo , Cadmio/farmacología , Cobre/farmacología , Hojas de la Planta/citología , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/metabolismo , Semillas/efectos de los fármacos , Semillas/metabolismo

RESUMEN

In order to assess the effect of lindane exposure on gene expression in tilapia (Oreochromis niloticus), twenty male fish were individually weighted and injected intraperitoneally with a single dose of lindane (19.09 mg/kg bw) using corn oil as a carrier vehicle, while a second group of twenty male fish (controls) was only injected with the carrier vehicle. Groups of four fish each were then sacrificed at 3, 6, 12, 18 and 24h after treatment application and total RNA was extracted from liver tissue. The differential display (DD) technique was then used to identify differentially expressed cDNA fragments between treatment and control fish. A total of fifty cDNA fragments were isolated and sequenced, from which only four showed homology with genes previously described in other fish species, namely the immunoglobulin heavy chain (IgH), coagulation factor V (FV), casein kinase 2 alpha (CK2a), and the receptor protein-tyrosine-like phosphatase (RPT-LP). The expression of such genes was confirmed using quantitative real time-polymerase chain reaction (QRT-PCR). Results showed that lindane exposure triggered the differential expression of these genes during the first 6, 18 and 24h subsequent to treatment application, suggesting that lindane exposure can trigger a rapid immune system response in tilapias.

Asunto(s)

Cíclidos/genética , Proteínas de Peces/genética , Perfilación de la Expresión Génica , Regulación de la Expresión Génica/efectos de los fármacos , Hexaclorociclohexano/toxicidad , Contaminantes Químicos del Agua/toxicidad , Animales , Quinasa de la Caseína II/genética , Factor V/genética , Perfilación de la Expresión Génica/métodos , Hexaclorociclohexano/administración & dosificación , Cadenas Pesadas de Inmunoglobulina/genética , Inyecciones Intraperitoneales , Masculino , ARN Mensajero/metabolismo , Proteínas Tirosina Fosfatasas Similares a Receptores/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Secuencia de ADN , Factores de Tiempo , Contaminantes Químicos del Agua/administración & dosificación

RESUMEN

The suitability of using helminth communities as bioindicators of environmental quality of the Yucatan coastal lagoons status was tested on the checkered puffer (Spheroides testudineus) in four coastal lagoons along the Yucatan coast. The concentration of chemical pollutants in sediments, water quality parameters, helminth infracommunity characteristics, as well as fish physiological biomarkers, including EROD (7-ethoxyresorufin-O-deethylase) and catalase activities, were measured. Results from sediment analyses demonstrated the presence of hydrocarbons, organochlorine pesticides and polychlorinated biphenyls at varying concentrations, some of which exceeded the Probability Effect Level (PEL). Significant negative associations among organochlorine pesticides, infracommunity characteristics and fish physiological responses were observed in most of the lagoons. Results suggest that EROD activity and parasite infracommunity characteristics could be useful tools to evaluate the effects of chemical pollutants on the fish host and in the environment. Importantly, certain parasites appear to influence biomarker measurements, indicating that parasites should be considered in ecotoxicological studies.

Asunto(s)

Monitoreo del Ambiente/métodos , Helmintos/fisiología , Tetraodontiformes/parasitología , Contaminantes Químicos del Agua/análisis , Contaminación del Agua/análisis , Agua/química , Animales , Biomarcadores/análisis , Sedimentos Geológicos/química , Helmintos/aislamiento & purificación , México

RESUMEN

Polycyclic aromatic hydrocarbons (PAH) are the main components of emissions generated by coke oven factories and many of these chemicals are carcinogenic. The goal of this study was to examine changes in gene expression in two human cell lines, HepG2 and A549, induced by exposure to a soil extract containing PAH using microarry technology. Soil samples were obtained from the vicinity of a coke oven factory in northeastern Mexico. For comparison, the gene expression pattern induced by Benz[a]pyrene (BaP) was also analyzed. The number of altered genes by both treatments was 2-fold higher in hepatic than in pulmonary cells. Differentially-modulated genes in the two cell lines were identified and grouped by biological function using genomic databases. A group of nine genes up- and down-regulated by either the PAH extract or BaP were selected for validation by real-time PCR. The cellular functions of these PAH-responsive genes included: xenobiotic metabolism (CYP1A1 and CYP1B1), DNA repair (ERCC5), oxidative stress response and cell proliferation (FTH1 and PRDX1), protein degradation (PSMD7), ion transport (FXYD3), steroid biosynthesis (FDFT1), and signaling pathways (PTGER3). The real-time PCR analysis confirmed most of the microarray data with significant correlation. Additional studies are required to determine the mechanisms involved in the PAH-mediated modulation of these genes and to associate these changes with human health.

Asunto(s)

Carcinógenos/toxicidad , Contaminantes Ambientales/toxicidad , Expresión Génica/efectos de los fármacos , Hidrocarburos Policíclicos Aromáticos/toxicidad , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Coque/análisis , Recolección de Datos , Perfilación de la Expresión Génica , Humanos , Hibridación in Situ , Indicadores y Reactivos , Análisis de Secuencia por Matrices de Oligonucleótidos , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/genética , ARN Neoplásico/biosíntesis , ARN Neoplásico/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Contaminantes del Suelo/química , Contaminantes del Suelo/toxicidad , Xenobióticos/metabolismo

RESUMEN

Isolation of high-quality RNA of Avicennia germinans L. tissue is difficult due to high levels of phenols and other substances that interfere when using conventional procedures for the isolation. These substances not only decrease the yield but also the quality of RNA is almost poor. We present here a simple RNA protocol and fast methodology that effectively removes these contaminating substances without affecting the yield. The protocol developed is based on the SDS/phenol method with modifications including beta-mercaptoethanol to prevent oxidation of phenolic complexes, and phenol/chloroform extraction is introduced to remove proteins, genomic DNA, and secondary metabolites, and co-precipitated polysaccharides. Both A260/A230 and A260/A280 absorbance ratios of isolated RNA were around 2 and the yield was about 0.3 mg g(-1) fresh weight. Good-quality total RNA from leaves of Avicennia germinans could be easily isolated within 2 h by this protocol which avoided the limitation of plant materials and could provide total RNA for all kinds of further molecular studies.

Asunto(s)

Avicennia/genética , Hojas de la Planta/genética , ARN de Planta/genética , Cartilla de ADN , ADN de Plantas/genética , Electroforesis en Gel de Agar , ARN de Planta/aislamiento & purificación , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa

RESUMEN

Persistent Organic Pollutants (POPs) are still used for agricultural and disease vector control, as well as for industrial purposes. In the last decades, various studies have shown that fish are sensitive to the toxicological effects of certain POPs, including a large class of endocrine- disrupting chemicals (EDCs). In the present study, the relationship between of POPs and their effects using vitellogenin gene expression as biomarker of effect in hardhead catfish Ariopsis felis (Linnaeus, 1766) from three ecosystems in the Southern Gulf of Mexico and Yucatan Peninsula are discussed. Contaminant results showed that median concentrations of PCBs, HCHs, DDTs and Chlordanes were higher in Laguna de Terminos with respect to Celestun and Dzilam. In the same way, the vitellogenin gene expression was clearly over-expressed in fish collected from Terminos Lagoon. Principal Component Analysis showed that vitellogenin gene expression is related to the concentrations of total DDTs and PCBs, and negatively related to total Drins. Overall, this study represents the first tests exploring changes in molecular diagnostic indicators following exposure of several organic compounds in our country. Vitellogenin gene expressions associated with some endocrine disruptors detected in Terminos Lagoon were measured and we can now report clear changes in fish exposed.

Asunto(s)

Bagres/genética , Hidrocarburos Clorados/toxicidad , Plaguicidas/toxicidad , Vitelogeninas/genética , Contaminantes Químicos del Agua/toxicidad , Animales , Biomarcadores/metabolismo , Bagres/metabolismo , Ecosistema , Monitoreo del Ambiente , Expresión Génica/efectos de los fármacos , Hidrocarburos Clorados/metabolismo , Hígado/metabolismo , Masculino , México , Plaguicidas/metabolismo , ARN Mensajero/metabolismo , Agua de Mar , Contaminantes Químicos del Agua/metabolismo

RESUMEN

To evaluate the role of phytochelatins and metallothioneins in heavy metal tolerance of black mangrove Avicennia germinans, 3-month-old seedlings were exposed to cadmium or copper for 30 h, under hydroponic conditions. Degenerate Mt2 and PCS primers were synthesized based on amino acid and nucleotide alignment sequences reported for Mt2 and PCS in other plant species found in GenBank. Total RNA was isolated from A. germinans leaves and two partial fragments of metallothionein and phytochelatin synthase genes were isolated. Gene expression was evaluated with reverse transcripatase-polymerase chain reaction (RT-PCR) amplification technique. Temporal analysis showed that low Cd2+ and Cu2+ concentrations caused a slight (but not significant) increase in AvMt2 expression after a 16 h exposure time, while AvPCS expression showed a significant increase under the same conditions but only after 4h. Results strongly suggest that the rapid increase in AvPCS expression may contribute to Cd2+ and Cu2+ detoxification. Moreover, we found that A. germinans has the capacity to over-express both genes (AvMt2 and AvPCS), which may constitute a coordinated detoxification response mechanism targeting non-essential metals. Nonetheless, our results confirm that AvPCS was the most active gene involved in the regulation of essential metals (e.g., Cu2+) in A. germinans leaves.

Asunto(s)

Aminoaciltransferasas/efectos de los fármacos , Avicennia/efectos de los fármacos , Cadmio/toxicidad , Cobre/toxicidad , Metalotioneína/efectos de los fármacos , Contaminantes del Agua/toxicidad , Secuencia de Aminoácidos , Aminoaciltransferasas/biosíntesis , Aminoaciltransferasas/genética , Avicennia/genética , Avicennia/metabolismo , Secuencia de Bases , Cadmio/metabolismo , Cobre/metabolismo , Exposición a Riesgos Ambientales , Expresión Génica/efectos de los fármacos , Metalotioneína/biosíntesis , Metalotioneína/genética , Datos de Secuencia Molecular , Hojas de la Planta/química , Reacción en Cadena de la Polimerasa , Alineación de Secuencia , Factores de Tiempo , Contaminantes del Agua/metabolismo

RESUMEN

The toxic effects of cadmium on the photosynthetic apparatus of Avicennia germinans were evaluated by means of the chlorophyll fluorescence transient O-J-I-P. The chlorophyll fluorescence transients were recorded in vivo with high time resolution and analyzed according to the OJIP-test that can quantify the performance of photosystem II. Cadmium-treated plants showed a decrease in yield for primary photochemistry, TR0/ABS. The performance index of photosystem II (PSII), PI(ABS), decreased due to cadmium treatment. This performance index is the combination of the indexes of three independent parameters: (1) total number of active reaction centers per absorption (RC/ABS), (2) yield of primary photochemistry (TR0/ABS), and (3) efficiency with which a trapped exciton can move an electron into the electron transport chain (ET0/TR0). Additionally, the F0/Fv registered the highest sensitivity to the metal, thus indicating that the water-splitting apparatus of the oxidizing side of PSII is the primary site of action of cadmium. In summary, cadmium affects several targets of photosystem II. More specifically the main targets of cadmium, according to the OJIP-test, can be listed as a decrease in the number of active reaction centers and damage to the activity of the water-splitting complex.

Asunto(s)

Avicennia/fisiología , Cadmio/toxicidad , Fotosíntesis/efectos de los fármacos , Complejo de Proteína del Fotosistema II/efectos de los fármacos , Avicennia/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Cinética , Fotosíntesis/fisiología , Teoría Cuántica , Espectrometría de Fluorescencia