Environmental evaluation of the Reloncaví estuary in southern Chile based on lipophilic shellfish toxins as related to harmful algal blooms.

The Reloncaví estuary in southern Chile is famous for its aquaculture. However, recurring harmful algal blooms have adversely affected mussel production. Therefore, regular monitoring of algal toxins is urgently needed to better understand the contamination status of the estuary. In this study, we quantified 15 types of lipophilic shellfish toxins in Metri Bay in the Reloncaví estuary on a biweekly basis for 4 years. We identified algal species using microscopy and metabarcoding analysis. We also measured water temperature, salinity, chlorophyll-a, and dissolved oxygen to determine the potential relationships of these parameters with algal toxin production. Our results revealed the presence of a trace amount of pectenotoxin and the causal phytoplankton Dinophysis, as well as yessotoxin and the causal phytoplankton Protoceratium. Statistical analysis indicated that fluctuations in water temperature affected the detection of these toxins. Additionally, metabarcoding analysis detected the highly toxic phytoplankton Alexandrium spp. in some samples. Although our results suggest that the level of lipophilic shellfish toxins in Metri Bay during the study period was insignificantly low using our current LC-MS method, the confirmed presence of highly toxic algae in Metri Bay raises concerns, given that favorable environmental conditions could cause blooms.

Monitoring bacterial composition and assemblage in the Gulf of Corcovado, southern Chile: Bacteria associated with harmful algae.

Harmful Algal Blooms (HABs) have caused damage to the marine environment in Isla San Pedro in the Gulf of Corcovado, Chile. While rising water temperature and artificial eutrophication are the most discussed topics as a cause, marine bacteria is a recent attractive parameter as an algal bloom driver. This study monitored algal and bacterial compositions in the water of Isla San Pedro for one year using microscopy and 16S rRNA metabarcoding analysis, along with physicochemical parameters. The collected data were analyzed with various statistical tools to understand how the particle-associated bacteria (PA) and the free-living (FL) bacteria were possibly involved in algal blooms. Both FL and PA fractions maintained a stable bacterial composition: the FL fraction was dominated by Proteobacteria (α-Proteobacteria and γ-Proteobacteria), and Cyanobacteria dominated the PA fraction. The two fractions contained equivalent bacterial taxonomic richness (c.a. 8,000 Operational Taxonomic Units) and shared more than 50% of OTU; however, roughly 20% was exclusive to each fraction. The four most abundant algal genera in the Isla San Pedro water were Thalassiosira, Skeletonema, Chaetoceros, and Pseudo-nitzchia. Statistical analysis identified that the bacterial species Polycyclovorans algicola was correlated with Pseudo-nitzschia spp., and our monitoring data recorded a sudden increase of particle-associated Polycyclovorans algicola shortly after the increase of Pseudo-nitzschia, suggesting that P. algicola may have regression effect on Pseudo-nitzschia spp. The study also investigated the physicochemical parameter effect on algal-bacterial interactions. Oxygen concentration and chlorophyll-a showed a strong correlation with both FL and PA bacteria despite their assemblage differences, suggesting that the two groups had different mechanisms for interacting with algal species.

Heterosigma akashiwo in Patagonian Fjords: Genetics, Growth, Pigment Signature and Role of PUFA and ROS in Ichthyotoxicity.

Heterosigma akashiwo is the only raphidophyte described for Chilean waters. A recent 2021 fish-killing bloom event of this raphidophyte ignited scientific research, but the ichthyotoxic mechanism and environmental conditions that promote its growth are still unclear. This is the first study confirming the occurrence of H. akashiwo in Chilean waters on the basis of the region D1/D2 of the 28S ribosomal gene. The pigment signature of the CREAN_HA03 strain revealed chlorophyll-a, fucoxanthin, and violaxanthin as the most abundant pigments, but profiles were variable depending on culture and field conditions. A factorial temperature−salinity growth experiment showed a maximal growth rate of 0.48 d−1 at 17 °C and 35 in salinity, but reached a maximal cell abundance of ~50,000 cells mL−1 at 12 °C and 25 in salinity. The fatty acid profile included high levels of saturated (16:0) and polyunsaturated (18:4 ω3; 20:5 ω3) fatty acids, but superoxide production in this strain was low (~0.3 pmol O2− cell−1 h−1). The RTgill-W1 bioassay showed that the H. akashiwo strain was cytotoxic only at high cell concentrations (>47,000 cells mL−1) and after cell rupture. In conclusion, salmon mortality during H. akashiwo bloom events in Patagonian fjords is likely explained by the high production of long-chain PUFAs at high cell densities, but only in the presence of high ROS production.

Toxic Alexandrium catenella expanding northward along the Chilean coast: New risk of paralytic shellfish poisoning off the Bío-Bío region (36° S).

In Chile, the toxic dinoflagellate A. catenella shows an apparent oceanic range expansion from south to the north since its first detection in 1972 in the Magallanes Region (56° S). Until 2017, A. catenella detections were restricted to a geographic area between Magallanes to Los Rios Regions (40° S). The establishment of a monitoring program in the offshore Pacific coast allowed the detection of A. catenella between 2018 and 2019 in northern areas off the Bío-Bío Region (36°S). Monoclonal cultures established from the Bío-Bío coast were genetically identified, and PSTs screened. Phylogenetic analyses determined that the Bío-Bío isolates aggregated in Group I ribotype (previously A. tamarense or A. fundyense) and the presence of PSTs analogs were confirmed. It is the northernmost detection of the toxic dinoflagellate A. catenella in the Pacific coast of Chile. These results have important implications for species monitoring and governmental management in the Bío-Bío Region.

Disentangling the environmental processes responsible for the world's largest farmed fish-killing harmful algal bloom: Chile, 2016.

The dictyochophyte microalga Pseudochattonella verruculosa was responsible for the largest farmed fish mortality ever recorded in the world, with losses for the Chilean salmon industry amounting to US$ 800 M in austral summer 2016. Super-scale climatic anomalies resulted in strong vertical water column stratification that stimulated development of a dynamic P. verruculosa thin layer (up to 38 µg chl a L-1) for several weeks in Reloncaví Sound. Hydrodynamic modeling (MIKE 3D) indicated that the Sound had extremely low flushing rates (between 121 and 200 days) in summer 2016. Reported algal cell densities of 7000-20,000 cells mL-1 generated respiratory distress in fish that was unlikely due to low dissolved oxygen (permanently >4 mg L-1). Histological examination of salmon showed that gills were the most affected organ with significant tissue damage and circulatory disorders. It is possible that some of this damage was due to a diatom bloom that preceded the Pseudochattonella event, thereby rendering the fish more susceptible to Pseudochattonella. No correlation between magnitude of fish mortality and algal cell abundance nor fish age was evident. Algal cultures revealed rapid growth rates and high cell densities (up to 600,000 cells mL-1), as well as highly complex life cycle stages that can be easily overlooked in monitoring programs. In cell-based bioassays, Chilean P. verruculosa was only toxic to the RTgill-W1 cell line following exposures to high cell densities of lysed cells (>100,000 cells mL-1). Fatty acid profiles of a cultured strain showed elevated concentrations of potentially ichthyotoxic, long-chain polyunsaturated fatty acids (PUFAs) (69.7% ± 1.8%)- stearidonic (SDA, 18:4ω3-28.9%), and docosahexaenoic acid (DHA, 22:6ω3-22.3%), suggesting that lipid peroxidation may help to explain the mortalities, though superoxide production by Pseudochattonella was low (< 0.21 ± 0.19 pmol O2- cell-1 h-1). It therefore remains unknown what the mechanisms of salmon mortality were during the Pseudochattonella bloom. Multiple mitigation strategies were used by salmon farmers during the event, with only delayed seeding of juvenile fish into the cages and towing of cages to sanctuary sites being effective. Airlift pumping, used effectively against other fish-killing HABs in the US and Canada was not effective, perhaps because it brought subsurface layers of Pseudochattonella to the surface, or and it also may have lysed the fragile cells, rendering them more lethal. The present study highlights knowledge gaps and inefficiency of contingency plans by the fish farming industry to overcome future fish-killing algal blooms under future climate change scenarios. The use of new technologies based on molecular methods for species detection, good farm practices by fish farms, and possible mitigation strategies are discussed.

Unraveling the Karenia selliformis complex with the description of a non-gymnodimine producing Patagonian phylotype.

Karenia selliformis is a bloom-forming toxic dinoflagellate known for production of gymnodimines (GYMs) and causing mass mortalities of marine fauna. Blooms have been reported from coastal waters of New Zealand, Mexico, Tunisia, Kuwait, Iran, China and Chile. Based on molecular phylogeny, morphology, toxin production, pigment composition and cell growth of Chilean K. selliformis isolated in 2018 (CREAN_KS01 and CREAN_KS02), this study revealed a more complex diversity within this species than previously thought. A phylogenetic reconstruction based on the large sub-unit ribosomal nucleotide (LSU rDNA) and Internal Transcriber Spacer (ITS) sequences of 12 worldwide isolates showed that within the K. selliformis clade there are at least two different phylotypes with clear phenotypic differences. Morphological differences related to the dorsal-ventral compression, shape of the hyposome and the presence of pores on the left lobe of the hyposome. A comparison of pigment signatures among worldwide isolates revealed the existence of both acyl-oxyfucoxanthin and fucoxanthin-rich strains within the phylotypes. A LC-MS/MS screening on both Chilean 2018 K. selliformis strains showed for first time no GYMs production among cultured clones of this species. However, both CREAN_KS01 and CREAN_KS02 contained two compounds with the same mass transition as brevenal, a brevetoxin related compound. A fish gill cell-based assay showed that the CREAN_KS02 strain was highly cytotoxic but pure GYM standard did not exhibit loss of cell viability, even at cell concentrations equivalent or exceeding those reported in nature. The fatty acid profile of CREAN_KS02 included high levels of saturated (14:0; 16:0) and polyunsaturated (18:3ω6+18:5ω3; 22:6ω3) fatty acids but superoxide production in this strain was low (0.86±0.53 pmol O2- cell-1 h-1). A factorial T-S growth experiment using the CREAN_KS02 strain showed a µmax of 0.41±0.03 d-1 at high salinity and temperature, which points to its optimal environmental niche in offshore waters during the summer season. In conclusion, the present study provides evidence for significant genetic and phenotypic variability among worldwide isolates, which points to the existence of a K. selliformis "species complex". The massive fauna mortality during K. selliformis bloom events in the Chilean coast cannot be explained by GYMs nor brevetoxins, but can to a large extent be accounted for by the high production of long-chain PUFAs and/or still uncharacterized highly toxic compounds.

Tipificación de serotipos del virus del papiloma humano de alto riesgo / Typification of high-risk human papilomavirus serotypes

Resumen: OBJETIVO: Identificar los serotipos más frecuentes de virus del papiloma humano mediante pruebas al azar en pacientes previamente diagnosticadas con cáncer cervicouterino. MATERIALES Y MÉTODOS: Estudio prospectivo y observacional, efectuado en pacientes con displasia cervical, atendidas en el Hospital Regional Materno Infantil de Alta Especialidad de Nuevo León, Monterrey, entre enero y marzo de 2016. Criterios de inclusión: pacientes mayores de 18 años, que acudieron a la unidad médica para seguimiento y control ginecológico, con reporte anormal en la prueba de Papanicolaou, confirmado por histopatología, mediante biopsia dirigida por colposcopia. Criterios de exclusión: mujeres con histerectomía total por indicación de enfermedad benigna, sin antecedente de neoplasia intracervical; mayores a 70 años después de 3 citologías cervicales negativas en la década previa; pacientes que recibieron quimioterapia, radioterapia u otros tratamientos farmacológicos y quienes acudieron a revisión médica durante su ciclo menstrual. Para el análisis de los datos se utilizó estadística descriptiva. RESULTADOS: Se registraron 30 pacientes. Las clasificaciones más frecuentes de neoplasia cervical fueron: NIC-1 (n = 15), NIC-2 (n = 9) y NIC-3 (n = 6). Todas las pacientes analizadas tuvieron, al menos, un serotipo de VPH de alto riesgo. Los serotipos identificados con mayor frecuencia fueron el 31 y 33 (n = 18). En 18 pacientes se encontraron 6 o más serotipos de VPH. De 15 pacientes con lesiones de alto grado, 8 tuvieron la asociación de serotipos 31 y 33, y en 6 se identificó un serotipo aislado (16 y 51). CONCLUSIONES: Los serotipos identificados con mayor frecuencia fueron el 31 y 33. Desafortunadamente, la vacuna nonavalente que protege contra los serotipos más frecuentes de VPH no se encuentra disponible en Latinoamérica.

Abstract: OBJECTIVE: To identify the most frequent serotypes of human papillomavirus through random testing of patients previously diagnosed with cervical cancer. MATERIALS AND METHODS: A prospective, observational study carried out in patients with cervical dysplasia, treated at the High Specialty Regional Maternal and Child Hospital of Nuevo León, Monterrey. Inclusion criteria: patients over 18 years of age, who attended the Dysplasia Clinic of the High Specialty Regional Maternal and Child Hospital for gynecological follow-up and control, with an abnormal result in the Papanicolaou test, confirmed by histopathology, by means of colposcopy-directed biopsy. Before the procedures (cervical cytology), Exclusion criteria: women with total hysterectomy due to indications of benign disease, without a history of intracervical neoplasia; older than 70 years after 3 negative cervical cytology in the previous decade; patients who received chemotherapy, radiotherapy or other pharmacological treatments and who received medical check-ups during their menstrual cycle. Descriptive statistics were used for data analysis. RESULTS: 30 patients were registered. The most frequent classification of cervical neoplasia was: CIN1 (n = 15), CIN2 (n = 9) and CIN3 (n = 6). All the patients analyzed had at least one high-risk HPV serotype. The most frequently identified serotypes were 31 and 33 (n = 18 of 30). 6 or more HPV serotypes were found in 18 patients. Of 15 patients with high-grade lesions, 8 had the association of serotypes 31 and 33, and in 6 an isolated serotype was identified (16 and 51). CONCLUSIONS: The most frequently identified serotypes were 31 and 33. Unfortunately, the nonavalent vaccine that protects against the most frequent serotypes of HPV is not available in Latin America.

Factores de riesgo modificables del cáncer de mama: una comparación entre mujeres menores y mayores de 40 años / Modifiable risk factors for breast cancer: a comparison between women younger and older than 40 years-old

Resumen OBJETIVO: Analizar la repercusión diferencial de los principales factores de riesgo modificables asociados con el cáncer de mama en pacientes menores y mayores de 40 años. MATERIALES Y MÉTODOS: Estudio de cohorte, retrospectivo, observacional y descriptivo. Se reunió la información de las pacientes con diagnóstico o tratamiento de cáncer de mama atendidas en un centro hospitalario del Noreste de México entre enero de 2016 y diciembre de 2017. La asociación entre las distintas variables y los grupos etarios se determinó con la prueba de la χ2 de Pearson y se consideraron estadísticamente significativos los valores con p < 0.05. RESULTADOS: Se revisaron 524 expedientes clínicos de pacientes con cáncer de mama, con límites de edad entre 22 y 99 y se seleccionaron las menores de 40 años (n = 75) que representaron 14.31% del total de las pacientes atendidas, porcentaje que coincide con la prevalencia de cáncer de mama en mujeres jóvenes reportada en la bibliografía mexicana. Se encontró un efecto similar en el riesgo de padecer cáncer de mama entre ambos grupos con los siguientes factores de riesgo modificables: nuliparidad, tabaquismo, consumo de alcohol, sedentarismo y anticoncepción hormonal. La obesidad (IMC superior a 30) tuvo mayor repercusión en mujeres de más de 40 años. CONCLUSIÓN: La prevalencia de cáncer de mama en las pacientes jóvenes fue del doble de lo reportado en el ámbito internacional. Es necesario el control de peso en mujeres menores de 40 años, que permita reducir la incidencia del cáncer de mama triple negativo en esta población. Asimismo, se recomienda el control de los otros factores de riesgo modificables porque, aunque no parecen afectar significativamente a las mujeres jóvenes, su control tiene una repercusión positiva en la prevención del cáncer de mama en todos los grupos etarios.

Abstract OBJECTIVE: To analyze the differential impact of the main modifiable risk factors associated with breast cancer among patients younger than 40 years of age. MATERIALS AND METHODS: Cohort, retrospective, observational and descriptive study. The information of the patients with diagnosis or treatment of breast cancer treated in a hospital in Northeast Mexico between January 2016 and December 2017 was collected. The association between the different variables and the age groups was determined with the test of Pearson's χ2 and the values p < 0.05 were considered statistically significant. RESULTS: 524 clinical records of patients with breast cancer were reviewed, with age limits between 22 and 99 years. From this group, patients under 40 years of age (n = 75) were selected, representing 14.31% of the total number of patients treated, a percentage that coincides with the prevalence of breast cancer in young women reported in the Mexican literature. A similar impact was found on the risk of breast cancer between both groups with the following modifiable risk factors: nulliparity, smoking, alcohol consumption, sedentary lifestyle and hormonal contraception. Obesity (BMI ≥ 30) had a greater impact on women ≥ 40 years. CONCLUSION: The prevalence of breast cancer in young patients was double what was reported internationally. Weight control is necessary in women under 40 years of age, which allows reducing the incidence of triple negative breast cancer in this population. Likewise, the control of the other modifiable risk factors is recommended because, although they do not seem to significantly affect young women, their control has a positive impact on the prevention of breast cancer in all age groups.

Prevalence of high-grade perineal tear during labor in Mexican adolescents / Prevalencia de desgarro de alto grado en parto de adolescentes mexicanas

Abstract Introduction: There is a high rate of deliveries in adolescents in Mexico. This age group is vulnerable to obstetric complications, including lacerations of the anal sphincter. Objective: To determine the prevalence of third and fourth degree perineal tears in adolescents during childbirth, and to evaluate risk factors in comparison with deliveries with lacerations of adult women. Methods: All obstetric care episodes were reviewed from a public tertiary hospital data in Monterrey, Mexico in 2014. Age, primiparity, delivery instrumentation, episiotomy, body mass index, product weight and tear´s degree were documented at the deliveries with tears of third and fourth degree. Results: The prevalence of third and fourth degree tears of 2.0% was found in the general population, being adolescents the most affected with 2.5%. The unadjusted odds ratio of high-grade tears in adolescent females at delivery, compared to adult females, was 1.36 (95% CI = 0.99-1.86, p= 0.05). No difference was found when comparing risk factors among high-grade tear deliveries in adolescents versus adults. Conclusions: A higher prevalence than previous reported for high grade tears during delivery was found. The data suggest adolescence as a risk factor for high-grade tears during delivery.

Resumen Introducción: En México hay una elevada tasa de partos en adolescentes. Este grupo es vulnerable para complicaciones obstétricas, entre ellas laceración del esfínter anal. Objetivo: Conocer la prevalencia de desgarros perineales de tercer y cuarto grado en adolescentes durante el parto y evaluar factores de riesgo en comparación con partos con laceración de mujeres adultas. Métodos: Se revisaron todas las atenciones obstétricas en un hospital publico de tercer nivel en Monterrey, Nuevo León, México en el año 2014. Se documentó edad, primiparidad, instrumentación del parto, realización de episiotomía, índice de masa corporal, peso del producto y grado del desgarro en los partos que presentaron desgarros de tercer y cuarto grado Resultados: Se encontró una prevalencia general de 2.0% de desgarros de tercer y cuarto grado y en adolescentes de 2.5%. La razón de momios sin ajustar de desgarros de alto grado en mujeres adolescentes en comparación con mujeres adultas fue de 1.36 (IC 95%= 0.99-1.86, p= 0.05). No se encontró diferencia al comparar factores de riesgo entre los partos con desgarro de alto grado en adolescentes contra adultas. Conclusiones: Se encontró una prevalencia mayor a lo reportado de desgarros de alto grado durante el parto. Los datos sugieren a la adolescencia como factor de riesgo para desgarros de alto grado.

Prevalence of high-grade perineal tear during labor in Mexican adolescents.

INTRODUCTION: There is a high rate of deliveries in adolescents in Mexico. This age group is vulnerable to obstetric complications, including lacerations of the anal sphincter. OBJECTIVE: To determine the prevalence of third and fourth degree perineal tears in adolescents during childbirth, and to evaluate risk factors in comparison with deliveries with lacerations of adult women. METHODS: All obstetric care episodes were reviewed from a public tertiary hospital data in Monterrey, Mexico in 2014. Age, primiparity, delivery instrumentation, episiotomy, body mass index, product weight and tear´s degree were documented at the deliveries with tears of third and fourth degree. RESULTS: The prevalence of third and fourth degree tears of 2.0% was found in the general population, being adolescents the most affected with 2.5%. The unadjusted odds ratio of high-grade tears in adolescent females at delivery, compared to adult females, was 1.36 (95% CI = 0.99-1.86, p= 0.05). No difference was found when comparing risk factors among high-grade tear deliveries in adolescents versus adults. CONCLUSIONS: A higher prevalence than previous reported for high grade tears during delivery was found. The data suggest adolescence as a risk factor for high-grade tears during delivery.

INTRODUCCIÓN: En México hay una elevada tasa de partos en adolescentes. Este grupo es vulnerable para complicaciones obstétricas, entre ellas laceración del esfínter anal. OBJETIVO: Conocer la prevalencia de desgarros perineales de tercer y cuarto grado en adolescentes durante el parto y evaluar factores de riesgo en comparación con partos con laceración de mujeres adultas. MÉTODOS: Se revisaron todas las atenciones obstétricas en un hospital publico de tercer nivel en Monterrey, Nuevo León, México en el año 2014. Se documentó edad, primiparidad, instrumentación del parto, realización de episiotomía, índice de masa corporal, peso del producto y grado del desgarro en los partos que presentaron desgarros de tercer y cuarto grado. RESULTADOS: Se encontró una prevalencia general de 2.0% de desgarros de tercer y cuarto grado y en adolescentes de 2.5%. La razón de momios sin ajustar de desgarros de alto grado en mujeres adolescentes en comparación con mujeres adultas fue de 1.36 (IC 95%= 0.99-1.86, p= 0.05). No se encontró diferencia al comparar factores de riesgo entre los partos con desgarro de alto grado en adolescentes contra adultas. CONCLUSIONES: Se encontró una prevalencia mayor a lo reportado de desgarros de alto grado durante el parto. Los datos sugieren a la adolescencia como factor de riesgo para desgarros de alto grado.

[Factors associated with successful vaginal birth in women with a cesarean section history]. / Factores asociados con éxito en el parto de mujeres con antecedente de cesárea.

UNLABELLED: BAKCGROUND: Caesarean section is the main proceedings for ending of pregnancy in the world, and currently represents a public health problem. Some factors that benefit the likelihood of vaginal birth after a previous C-section have been described in literature, with scoring tools designed to predict success for trial of labor after a previous cesarean. There are few studies that identify predictors of success for vaginal delivery in Latin-American patients. OBJECTIVE: To identify predictive factors associated to vaginal delivery success in patients with a prior cesarean delivery. MATERIAL AND METHOD: Case-control study. We included patients with one previous cesarean delivery admitted at our hospital. The variables analyzed with a logistic regression system to predict vaginal delivery success probabilities. RESULTS: A total of 11 60 patients were included, 668 underwent C-section (considered control group), and 492 patients had a vaginal delivery (considered study group). The Factors associated to vaginal birth after cesarean delivery were maternal age (25.1±5.4 vs 24.7±5.5 years old, OR 0.967, p<0.05), fetal weight (3,253±389 vs 3,383±452 g, OR 0.99, p<0.05), previous vaginal delivery (49 vs 1 8.4%, OR 2.97, p<0.05) and spontaneous labor (90.8 vs 74.1%, OR 3.68, p<0.05, respectively). CONCLUSION: Maternal age, fetal weight, previous vaginal delivery and spontaneous labor were associated with vaginal delivery success in patients with a previous cesarean delivery.

Next-generation transcriptome characterization in three Nacella species (Patellogastropoda: Nacellidae) from South America and Antarctica.

The southern tip of South America and Antarctica are particularly interesting due to many genera and also species currently sharing between both areas. The genus Nacella (Patellogastropoda: Nacellidae) is distributed in different regions of South America and Antarctica living preferentially on rocks and boulders and grazing on algae, diatoms and bacterial films. We described the transcriptomes of three Nacella species, Nacella concinna (Strebel, 1908), inhabiting the Antarctic Peninsula; Nacella magallanica (Gmelin, 1791), from Patagonia and Nacella clypeater (Lesson, 1831), from central Chile. In total, we obtained over 20,000 contigs with an average length of 583bp. Homologous protein coding genes (PCGs) for mitochondrial genome of the three species were characterized and a database of molecular markers was also generated. This study represents the first publicly available report on pyrosequencing data for patellogastropod species, and provides an important comparative resource for studies in ecophysiology and evolutionary adaptation in marine invertebrate species.

Transcriptome analysis in Concholepas concholepas (Gastropoda, Muricidae): mining and characterization of new genomic and molecular markers.

The marine gastropod Concholepas concholepas, locally known as the "loco", is the main target species of the benthonic Chilean fisheries. Genetic and genomic tools are necessary to study the genome of this species in order to understand the molecular basis of its development, growth, and other key traits to improve the management strategies and to identify local adaptation to prevent loss of biodiversity. Here, we use pyrosequencing technologies to generate the first transcriptomic database from adult specimens of the loco. After trimming, a total of 140,756 Expressed Sequence Tag sequences were achieved. Clustering and assembly analysis identified 19,219 contigs and 105,435 singleton sequences. BlastN analysis showed a significant identity with Expressed Sequence Tags of different gastropod species available in public databases. Similarly, BlastX results showed that only 895 out of the total 124,654 had significant hits and may represent novel genes for marine gastropods. From this database, simple sequence repeat motifs were also identified and a total of 38 primer pairs were designed and tested to assess their potential as informative markers and to investigate their cross-species amplification in different related gastropod species. This dataset represents the first publicly available 454 data for a marine gastropod endemic to the southeastern Pacific coast, providing a valuable transcriptomic resource for future efforts of gene discovery and development of functional markers in other marine gastropods.