RESUMEN

The collective involvement of virulence markers of Escherichia coli as an emerging pathogen associated with periodontitis remains unexplained. This study aimed to implement an in vitro model of infection using a human epithelial cell line to determine the virulome expression related to the antibiotic and disinfectant resistance genotype and pulse field gel electrophoresis (PFGE) type in E. coli strains isolated from patients with periodontal diseases. We studied 100 strains of E. coli isolated from patients with gingivitis (n = 12), moderate periodontitis (n = 59), and chronic periodontitis (n = 29). The identification of E. coli and antibiotic and disinfectant resistance genes was performed through PCR. To promote the expression of virulence genes in the strains, an in vitro infection model was used in the human epithelial cell line A549. RNA was extracted using the QIAcube robotic equipment and reverse transcription to cDNA was performed using the QuantiTect reverse transcription kit (Qiagen). The determination of virulence gene expression was performed through real-time PCR. Overall, the most frequently expressed adhesion genes among the isolated strains of gingivitis, moderate periodontitis, and chronic periodontitis were fimH (48%), iha (37%), and papA (18%); those for toxins were usp (33%); those for iron acquisition were feoB (84%), fyuA (62%), irp-2 (61%), and iroN (35%); those for protectins were traT (50%), KpsMT (35%), and ompT (28%); and those for pathogenicity islands were malX (45%). The most common antibiotic and disinfectant resistance genes among gingivitis, moderate periodontitis, and chronic periodontitis strains were sul-2 (43%), blaSHV (47%), blaTEM (45%), tet(A) (41%), dfrA1 (32%), marR-marO (57%), and qacEA1 (79%). The findings revealed the existence of a wide distribution of virulome expression profiles related to the antibiotic and disinfectant resistance genotype and PFGE type in periodontal strains of E. coli. These findings may contribute toward improving the prevention and treatment measures for periodontal diseases associated with E. coli.

Asunto(s)

Antibacterianos , Desinfectantes , Farmacorresistencia Bacteriana , Infecciones por Escherichia coli , Escherichia coli , Factores de Virulencia , Humanos , Escherichia coli/genética , Escherichia coli/efectos de los fármacos , Escherichia coli/patogenicidad , Factores de Virulencia/genética , Antibacterianos/farmacología , Infecciones por Escherichia coli/microbiología , Farmacorresistencia Bacteriana/genética , Desinfectantes/farmacología , Periodontitis/microbiología , Virulencia/genética , Células A549 , Células Epiteliales/microbiología , Genotipo , Adulto , Femenino , Masculino , Persona de Mediana Edad , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Electroforesis en Gel de Campo Pulsado

RESUMEN

Less than 15-20% of patients who meet the criteria for hereditary breast and ovarian cancer (HBOC) carry pathogenic coding genetic mutations, implying that other molecular mechanisms may contribute to the increased risk of this condition. DNA methylation in peripheral blood has been suggested as a potential epigenetic marker for the risk of breast cancer (BC). We aimed to discover methylation marks in peripheral blood associated with BC in 231 pre-treatment BC patients meeting HBOC criteria, testing negative for coding pathogenic variants, and 156 healthy controls, through methylation analysis by targeted bisulfite sequencing on 18 tumor suppressor gene promoters (330 CpG sites). We found i) hypermethylation in EPCAM (17 CpG sites; p = 0.017) and RAD51C (27 CpG sites; p = 0.048); ii) hypermethylation in 36 CpG-specific sites (FDR q < 0.05) in the BC patients; iii) four specific CpG sites were associated with a higher risk of BC (FDR q < 0.01, Bonferroni p < 0.001): cg89786999-FANCI (OR = 1.65; 95% CI:1.2-2.2), cg23652916-PALB2 (OR = 2.83; 95% CI:1.7-4.7), cg47630224-MSH2 (OR = 4.17; 95% CI:2.1-8.5), and cg47596828-EPCAM (OR = 1.84; 95% CI:1.5-2.3). Validation of cg47630224-MSH2 methylation in one Australian cohort showed an association with 3-fold increased BC risk (AUC: 0.929; 95% CI: 0.904-0.955). Our findings suggest that four DNA methylation CpG sites may be associated with a higher risk of BC, potentially serving as biomarkers in patients without detectable coding mutations.

RESUMEN

Introduction: This work represents the first attempt to obtain evidence of the validity of an entrepreneurial intention questionnaire in the adolescent population of a Latin American or Caribbean country. The objectives are to study the factor structure, the reliability, the external validity and to test the gender invariance of the Entrepreneurial Intention Questionnaire, in its adaptation for adolescents. Method: The sample consisted of 708 adolescents from the Dominican Republic with a mean age of 15.49, 65.2% of whom were women and 35.8% were men. Analyses included confirmatory factor analysis, Cronbach's Alpha and Omega scores for reliability, correlations, and a gender invariance routine. Finally, latent means of females and males are compared. Results: The confirmatory factor analysis showed a good fit to the data and the reliability results were adequate. In addition, the correlations with the Entrepreneurial Attitudes Scale for Students were positive and statistically significant. Also, strict gender invariance was successfully verified. Although males presented a higher subjective norm, females showed higher entrepreneurial intentions. Conclusions: The Entrepreneurial Intention Questionnaire shows adequate psychometric properties and proves useful in conducting research on the promotion of entrepreneurship in early stages.

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Introducción: Este trabajo supone el primer intento de obtener evidencias de validez de un cuestionario de intención emprendedora en adolescentes en un país de Latinoamérica y el Caribe. Tiene como objetivos reportar la estructura interna, fiabilidad, validez externa y probar la invarianza de género del Cuestionario de Intención Emprendedora en su adaptación para adolescentes. Método: La muestra está formada por 708 adolescentes de República Dominicana con una media edad de 15.49, un 65.2% de mujeres y un 35.8% hombres. Los análisis incluyeron análisis factorial confirmatorio, resultados de Alfa de Cronbach y Omega para la fiabilidad, correlaciones y una rutina de invarianza por género. Finalmente se compararon las medias latentes de hombres y mujeres. Resultados: El análisis factorial mostró un buen ajuste a los datos y los resultados de fiabilidad fueron adecuados. Además, las correlaciones con la Escala de Actitudes Emprendedoras para Estudiantes fueron positivas y estadísticamente significativas. También, se comprobó satisfactoriamente la invarianza estricta por género. Aunque los hombres presentaron mayor norma subjetiva, las mujeres mostraron una mayor intención emprendedora. Conclusiones: El Cuestionario de Intención Emprendedora muestra adecuadas propiedades psicométricas para que sea de utilidad en las investigaciones sobre la promoción del emprendimiento en etapas tempranas.

RESUMEN

Background: The SARS-CoV-2 virus has caused unprecedented mortality since its emergence in late 2019. The continuous evolution of the viral genome through the concerted action of mutational forces has produced distinct variants that became dominant, challenging human immunity and vaccine development. Aim and methods: In this work, through an integrative genomic approach, we describe the molecular transition of SARS-CoV-2 by analyzing the viral whole genome sequences from 50 critical COVID-19 patients recruited during the first year of the pandemic in Mexico City. Results: Our results revealed differential levels of the evolutionary forces across the genome and specific mutational processes that have shaped the first two epidemiological waves of the pandemic in Mexico. Through phylogenetic analyses, we observed a genomic transition in the circulating SARS-CoV-2 genomes from several lineages prevalent in the first wave to a dominance of the B.1.1.519 variant (defined by T478K, P681H, and T732A mutations in the spike protein) in the second wave. Conclusion: This work contributes to a better understanding of the evolutionary dynamics and selective pressures that act at the genomic level, the prediction of more accurate variants of clinical significance, and a better comprehension of the molecular mechanisms driving the evolution of SARS-CoV-2 to improve vaccine and drug development.

Asunto(s)

COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , COVID-19/epidemiología , Pandemias , México/epidemiología , Filogenia , Genoma Viral , Mutación

RESUMEN

Background: Individuals of Ashkenazi Jewish ancestry have been identified as having higher prevalence of specific pathogenic variants associated with susceptibility to specific rare and chronic diseases. In Mexico, the prevalence and composition of rare cancer predisposing germline variants in Ashkenazi Jewish individuals has not been evaluated. Aim and methods: We aimed to evaluate the prevalence of pathogenic variants by massive parallel sequencing in a panel of 143 cancer-predisposing genes in 341 women from the Ashkenazi Jewish community of Mexico, who were contacted and invited to participate in the study through the ALMA Foundation for Cancer Reconstruction. Pre- and posttest genetic counseling was given and a questionnaire on personal, gyneco-obstetric, demographic and lifestyle variables was conducted. From peripheral blood DNA, the complete coding region, and splicing sites of a panel of 143 cancer susceptibility genes, including 21 clinically relevant genes, were sequenced. The Mexican founder mutation BRCA1 ex9-12del [NC_000017.10(NM_007294):c. (825+1-826-1)_(4,589+1-4,590-1)del] was also evaluated. Results: Among study participants (mean age ±standard deviation: 47 ± 14) 15% reported a personal history of cancer (50/341). Fourteen percent of participants (48/341) were carriers of pathogenic and likely pathogenic variants distributed among seven high-risk genes (APC, CHEK2, MSH2, BMPR1A, MEN1, MLH1, and MSH6), whereas 18.2% (62/341) had variants of uncertain clinical significance in genes associated with breast and ovarian cancer susceptibility (list of genes with VUS). Pathogenic and likely pathogenic variants in 16 susceptibility genes with ambiguous or non-well-established risk association for cancer were detected in 17.6% (60/341) of participants. Sixty four percent of participants reported current alcohol consumption compared with the 39 percent prevalence of alcohol consumption in Mexican women. None of the participants carried the recurrent Ashkenazi and Mexican founder mutations in BRCA1 or BRCA2, but 2% (7/341) had pathogenic Ashkenazi Jewish founder variants in BLM. Conclusion: Our findings show a diverse pathogenic variant composition among the recruited individuals of Ashkenazi Jewish ancestry in Mexico consistent with being a high-risk population for genetic diseases, which warrants further investigation to adequately assess the burden of hereditary breast cancer in this group and implement appropriate preventative programs.

RESUMEN

This study aims to empirically test how learning strategies would fit into an undergraduate entrepreneur's profile.The design is cross-sectional with a sample of 527 The tested structural model adequately fits the data. It provided helpful information on learning strategies and entrepreneurial attitudes accounting for up to 20 % of variance of entrepreneurship intention. The learning strategies most related to entrepreneurial attitudes are those related to creativity, transference, and assess-ment of one's own performance. This paper provides for the first time evidence about the predictive power of several learning strategies on the entrepreneurial attitudes in connection with entrepreneurship intention (willingness and likelihood). This work increases our understanding of entrepreneurs' learning strategies, so that we can improve the design and implementation of educational resources to promote entrepreneurs' careers in emerging markets.Peruvian undergraduate students. A structural equation model was specified, estimated, and tested in Mplus 8.4. The model hypothesized direct effects of the different learning strategies on a factor of entrepreneurial attitudes (considering proactivity, pro-fessional ethics, empathy, innovation, autonomy, and risktaking dimensions) which, in turn, explained two indicators of entrepreneurship intention as outcomes.

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Este estudio busca comprobar empíricamente cómo las estrategias de aprendizaje encajarían en el perfil de un emprendedor de pregrado. El diseño es transversal, con una muestra de 527 estudiantes peruanos de pregrado. Se especificó, estimó y probó un modelo de ecuaciones estructurales en M plus 8.4. El modelo hipotetizó efectos directos de las diferentes estrategias de aprendizaje sobre un factor de actitudes emprendedoras (considerando las dimensiones de proactividad, ética profesional, empatía, innovación, autonomía y asunción de riesgos) que, a su vez, explicaban dos indicadores de intención emprendedora como resultados. El modelo estructural probado se ajusta adecuadamente a los datos. Proporcionó información útil sobre las estrategias de aprendizaje y las actitudes emprendedoras que explican hasta el 20 % de la varianza de la intención emprende-dora. Las estrategias de aprendizaje más relacionadas con las actitudes emprendedoras son las relaciona-das con la creatividad, la transferencia y la evaluación del propio rendimiento. Esta investigación proporciona la primera evidencia acerca del poder predictivo de varias estrategias de aprendizaje sobre las actitudes emprendedoras, en relación con la intención emprendedora (voluntad y probabilidad). Asimismo, aumenta nuestra comprensión de las estrategias de aprendizaje de los emprendedores, de modo que podamos mejorar el diseño y la implementación de recursos educativos para promover las carreras de los emprendedores en los mercados emergentes.

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Este estudo teve como objetivo verificar empiricamente como as estratégias de aprendizagem se encaixariam no perfil de um empreendedor de graduação. O desenho é transversal com uma amostra de 527 estudantes de graduação peruanos. Um modelo de equação estrutural foi especificado, estimado e testado no Mplus 8.4. O modelo hipotetizou efeitos diretos das diferentes estratégias de aprendizagem sobre um fator de atitudes empreendedoras (considerando as dimensões de proatividade, ética profissional, empatia, inovação, autonomia e assunção de riscos) que, por sua vez, explicaram como resultados dois indicadores de intenção empreendedora. O modelo estrutural testado ajustase adequadamente aos dados. Forneceu informações úteis sobre estratégias de aprendizagem e atitudes empreendedoras que explicam até 20 % da variância da intenção empreendedora. As estratégias de aprendizagem mais relacionadas com as atitudes em-preendedoras são as relacionadas com a criatividade, a transferência e a avaliação do próprio desempenho. Este trabalho fornece a primeira evidência analisando o poder preditivo de várias estratégias de aprendizagem sobre as atitudes empreendedoras em relação à intenção empreendedora (vontade e probabilidade). Este trabalho aumenta nossa compreensão das estratégias de aprendizagem dos empreendedores para que possamos melhorar o desenho e a implementação de recursos educacionais para fomentar a carreira dos empreendedores em mercados emergentes.

Asunto(s)

Humanos , Modelos Educacionales , Distribución por Edad , Educación Interprofesional

RESUMEN

Epigenetics affects gene expression and contributes to disease development by alterations known as epimutations. Hypermethylation that results in transcriptional silencing of tumor suppressor genes has been described in patients with hereditary cancers and without pathogenic variants in the coding region of cancer susceptibility genes. Although somatic promoter hypermethylation of these genes can occur in later stages of the carcinogenic process, constitutional methylation can be a crucial event during the first steps of tumorigenesis, accelerating tumor development. Primary epimutations originate independently of changes in the DNA sequence, while secondary epimutations are a consequence of a mutation in a cis or trans-acting factor. Secondary epimutations have a genetic basis in cis of the promoter regions of genes involved in familial cancers. This highlights epimutations as a novel carcinogenic mechanism whose contribution to human diseases is underestimated by the scarcity of the variants described. In this review, we provide an overview of secondary epimutations and present evidence of their impact on cancer. We propose the necessity for genetic screening of loci associated with secondary epimutations in familial cancer as part of prevention programs to improve molecular diagnosis, secondary prevention, and reduce the mortality of these diseases.

RESUMEN

In triple-negative breast cancer (TNBC), only 30% of patients treated with neoadjuvant chemotherapy achieve a pathological complete response after treatment and more than 90% die due to metastasis formation. The diverse clinical responses and metastatic developments are attributed to extensive intrapatient genetic heterogeneity and tumor evolution acting on this neoplasm. In this work, we aimed to evaluate genomic alterations and tumor evolution in TNBC patients with aggressive disease. We sequenced the whole exome of 16 lesions from four patients who did not respond to therapy, and took several follow-up samples, including samples from tumors before and after treatment, as well as from the lymph nodes and skin metastases. We found substantial intrapatient genetic heterogeneity, with a variable tumor mutational composition. Early truncal events were MCL1 amplifications. Metastatic lesions had deletions in RB1 and PTEN, along with TERT, AKT2, and CCNE1 amplifications. Mutational signatures 06 and 12 were mainly detected in skin metastases and lymph nodes. According to phylogenetic analysis, the lymph node metastases occurred at an early stage of TNBC development. Finally, each patient had three to eight candidate driving mutations for targeted treatments. This study delves into the genomic complexity and the phylogenetic and evolutionary development of aggressive TNBC, supporting early metastatic development, and identifies specific genetic alterations associated with a response to targeted therapies.

RESUMEN

Resumen En los últimos años el estudio de los ácidos nucleicos circulantes ha tenido grandes avances en el campo de la oncología, lo que ha permitido avanzar de forma importante en las aplicaciones clínicas de la biopsia líquida en diferentes áreas como el pronóstico, la estadificación, la predicción de recurrencia, la selección y monitorización de tratamientos, entre otros. Lo anterior se debe en gran parte al desarrollo de nuevas y mejores tecnologías, algunas de las cuales incluso han sido autorizadas para el diagnóstico y seguimiento clínico de ciertos tipos de cáncer. No obstante, la utilización de la biopsia líquida como herramienta de apoyo clínico sigue siendo objeto de estudio. Debido a la importancia que ha cobrado este avance tecnológico a nivel mundial, se realizó una revisión de literatura con el fin de establecer el estado actual del uso de biopsia líquida en oncología, así como sus aplicaciones clínicas actuales, con un énfasis en Latinoamérica.

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Abstract In recent years, the study of circulating nucleic acids has made great progress in the field of oncology, allowing for significant advances in clinical applications of liquid biopsy in diverse areas such as prognosis, staging, recurrence prediction, selection and monitoring of treatments, among others. This advance is largely due to the development of new and better technologies, some of which have even been validated for the diagnosis and clinical follow-up of certain types of cancer. However, the use of liquid biopsy as an additional tool in clinical oncology remains under study. Given the worldwide importance of this technological advance, a literature review was conducted to establish the current status of the use of liquid biopsy in oncology, as well as its current clinical applications, with a particular focus on Latin America.

Asunto(s)

Ácidos Nucleicos Libres de Células , Biopsia Líquida , Tecnología , Terapéutica , Predicción

RESUMEN

Triple-negative breast cancer (TNBC) presents a marked diversity at the molecular level, which promotes a clinical heterogeneity that further complicates treatment. We performed a detailed whole exome sequencing profile of 29 Mexican patients with long follow-up TNBC to identify genomic alterations associated with overall survival (OS), disease-free survival (DFS), and pathologic complete response (PCR), with the aim to define their role as molecular predictive factors of treatment response and prognosis. We detected 31 driver genes with pathogenic mutations in TP53 (53%), BRCA1/2 (27%), CDKN1B (9%), PIK3CA (9%), and PTEN (9%), and 16 operative mutational signatures. Moreover, tumors with mutations in BRCA1/2 showed a trend of sensitivity to platinum salts. We found an association between deficiency in DNA repair and surveillance genes and DFS. Across all analyzed tumors we consistently found a heterogeneous molecular complexity in terms of allelic composition and operative mutational processes, which hampered the definition of molecular traits with clinical utility. This work contributes to the elucidation of the global molecular alterations of TNBC by providing accurate genomic data that may help forthcoming studies to improve treatment and survival. This is the first study that integrates genomic alterations with a long follow-up of clinical variables in a Latin American population that is an underrepresented ethnicity in most of the genomic studies.

Asunto(s)

Mutación , Neoplasias de la Mama Triple Negativas/genética , Neoplasias de la Mama Triple Negativas/mortalidad , Adulto , Anciano , Trastornos por Deficiencias en la Reparación del ADN/genética , Femenino , Humanos , Estimación de Kaplan-Meier , Linfocitos Infiltrantes de Tumor/patología , Persona de Mediana Edad , Neoplasias de la Mama Triple Negativas/tratamiento farmacológico , Neoplasias de la Mama Triple Negativas/patología , Secuenciación del Exoma

RESUMEN

BACKGROUND: Prostate cancer is the most incident and one of the deadliest male cancers in Latin America. Treatment for patients with metastatic castration-resistant prostate cancer (mCRPC) includes androgen receptor signaling inhibitors such as abiraterone and enzalutamide, for which androgen receptor splice variant 7 (AR-V7) has emerged as a biomarker for primary resistance. Our study sought to analyze the potential economic impact of the use of AR-V7 detection as a treatment indicator in patients with mCRPC in three Latin American countries. MATERIALS AND METHODS: A hypothetical cost prediction model for the use of noninvasive circulating tumor cell-based AR-V7 testing as a treatment indicator for patients eligible for treatment with abiraterone/enzalutamide was conducted using available information on treatment and testing costs from Mexico, Argentina, and Colombia. RESULTS: At an estimated prevalence of AR-V7 positivity of 20%, the use of upfront AR-V7 genetic testing resulted in annual net savings of $9,801,669.97, $6,390,055.75, and $3,096,780.91 in Mexico, Argentina, and Colombia, respectively. A direct relationship between AR-V7 positivity prevalence and net savings was found. CONCLUSION: The use of a noninvasive AR-V7 detection assay as a treatment indicator tool in patients eligible for treatment with abiraterone or enzalutamide in Latin America could be a cost-effective approach for the management of these patients. Additional efforts are needed to accurately determine the incidence of castration-resistant prostate cancer cases and the prevalence of AR-V7 positivity in Latin America in order to predict the potential economic benefit of its clinical use. IMPLICATIONS FOR PRACTICE: In Latin America, prostate cancer is the most frequently diagnosed cancer in men, and the burden of this disease is expected to double in this region by 2030. Noninvasive detection of androgen receptor splice variant 7 (AR-V7) is being currently validated as a predictive biomarker for benefit with androgen receptor signaling inhibitor therapy in patients with metastatic castration-resistant prostate cancer (mCRPC). This hypothetical cost-saving analysis shows that AR-V7 testing in peripheral blood of patients with CRPC eligible for treatment with abiraterone or enzalutamide might represent a cost-effective strategy to select patients who will benefit from AR-axis-directed treatment in three Latin American countries.

Asunto(s)

Neoplasias de la Próstata Resistentes a la Castración , Androstenos , Benzamidas , Biomarcadores , Colombia/epidemiología , Resistencia a Antineoplásicos , Humanos , América Latina/epidemiología , Masculino , México/epidemiología , Nitrilos , Feniltiohidantoína , Neoplasias de la Próstata Resistentes a la Castración/tratamiento farmacológico , Isoformas de Proteínas , Receptores Androgénicos/genética

RESUMEN

Hereditary breast and ovarian cancer syndrome (HBOC) represents 5⁻10% of all patients with breast cancer and is associated with high-risk pathogenic alleles in BRCA1/2 genes, but only for 25% of cases. We aimed to find new pathogenic alleles in a panel of 143 cancer-predisposing genes in 300 Mexican cancer patients with suspicion of HBOC and 27 high-risk patients with a severe family history of cancer, using massive parallel sequencing. We found pathogenic variants in 23 genes, including BRCA1/2. In the group of cancer patients 15% (46/300) had a pathogenic variant; 11% (33/300) harbored variants with unknown clinical significance (VUS) and 74% (221/300) were negative. The high-risk group had 22% (6/27) of patients with pathogenic variants, 4% (1/27) had VUS and 74% (20/27) were negative. The most recurrent mutations were the Mexican founder deletion of exons 9-12 and the variant p.G228fs in BRCA1, each found in 5 of 17 patients with alterations in this gene. Rare VUS with potential impact at the protein level were found in 21 genes. Our results show for the first time in the Mexican population a higher contribution of pathogenic alleles in other susceptibility cancer genes (54%) than in BRCA1/2 (46%), highlighting the high locus heterogeneity of HBOC and the necessity of expanding genetic tests for this disease to include broader gene panels.

RESUMEN

Perna viridis was used as biomonitor to assess heavy metal levels in the Chacopata-Bocaripo lagoon axis, Venezuela, during rain and drought seasons. The mussels were weighed and measured. The metal concentrations were determined by atomic absorption spectrophotometry. For rain period, the order of bioavailability was: Cu>Ni>Mn>Co>Cd>Pb, and for drought: Cu>Mn>Ni>Co>Pb>Cd. The concentrations of Ni, Co, Cd and Pb showed significant differences (P<0.05) in both periods. There was higher metal accumulation during drought season, possibly related to upwelling, since it produces an increase in primary productivity, which translates more food into organisms, making metals bioavailable for mussels. Only Cu and Mn showed significant relationships between the size and metal concentration, during drought period, it may be because of the organisms need for these essential metals in different physiological processes.

Asunto(s)

Monitoreo del Ambiente/estadística & datos numéricos , Contaminantes Ambientales/análisis , Metales Pesados/análisis , Perna/metabolismo , Animales , Sequías , Monitoreo del Ambiente/métodos , Lluvia , Estaciones del Año , Espectrofotometría Atómica , Venezuela

RESUMEN

Objetivo. Determinar la concentración de glucosa no activadora de la movilidad espermática como componente de futuros diluyentes para la crioconservación de semen de Prochilodus magdalenae. Materiales y métodos. Se analizó semen inactivo de tres machos obtenido por inducción hormonal. Una submuestra de 0.25 µL de semen de cada macho fue depositada sobre una cámara de Makler y evaluada usando diferentes concentraciones de glucosa (0, 1, 2, 3, 4, 5, 6, 7, 8, 9 y 10%) mediante la adición de 75 µL de cada solución sobre el semen (n=3). De cada solución se determinó la osmolaridad, siendo de 0, 62, 124, 186, 250, 310, 360, 410, 472, 536 y 620 mOsm/kg, respectivamente, así como la del plasma seminal (~250–300 mOsm/kg). Mediante el software Sperm Class Analyzer (SCA) se determinó la velocidad curvilínea (VCL) y recta (VSL) (µm/seg), movilidad rápida (%), media (%) y lenta (%) y el porcentaje de espermatozoides inmóviles. El tiempo de activación de la movilidad (segundos) se obtuvo por cronometraje y visualización bajo microscopio de campo claro. Resultados. Concentraciones de 0 a 5% de glucosa produjeron activación de la movilidad espermática, no obstante, a partir de glucosa al 6% no fue detectada activación visual; sin embargo, SCA detectó movilidad total (7.2%), VCL (5.1 µm/seg) y VSL (1.7 µm/seg). A partir de glucosa al 7% el SCA detectó 100% de inmovilidad, no adquirida posteriormente con agua destilada. Conclusiones. La concentración de glucosa tiene efecto determinante en la viabilidad y activación de semen fresco. Una concentración de 6% de glucosa puede ser utilizada como solución no activadora de la movilidad espermática en futuros diluyentes para la crioconservación de semen de esta especie.

Asunto(s)

Animales , Atención , Peces , Glucosa , Semen , Motilidad Espermática

RESUMEN

Heavy metal distribution in superficial sedimenta ta Saco, Gulf of Cariaco, Sucre, Venezuela. The Gulf of Cariaco is a marine ecosystem with high primary productivity, which gives it an ecological and socioeconomic importance. Nevertheless, anthropogenic activities around the Gulf produce wastes that are deposited directly or by runoff into the sediments, and consequently, increases concentrations of metals in this ecosystem. The objective of this study was to determine the distribution of cadmium, copper, lead, manganese, nickel and zinc in geochemical fractions of surface sediments, using modified BCR sequential extraction procedure. The concentrations were measured using flame atomic absorption spectroscopy. In addition, the contents of soluble and exchangeable metals associated to carbonate fractions, determined by BCR, were compared with those determined by the method of Campanella. Samples were collected in 12 stations during June 2007. The applied methodologies were evaluated with a certified reference material of marine sediments (HISS-1) and the results indicated that these methods provide adequate accuracy and precision for the extraction of metals. The total metal concentrations (μg g-1) were, Cd: < limit of detection (LD)-5.0; Pb: 1.79-60.41; Cu: no detected (ND)-42.18; Zn: 25.13-104.57; Mn: 66.31-80.29 and Ni: 3.29-24.58. Cd, Cu, Ni and Pb at several stations, exceeded the Canadian Sediment Quality Guidelines of the Lowest Effect Levels (LEL). Cadmium was identified as being the most mobile of the elements, having the highest concentrations in soluble and exchangeable cations and carbonates. However, Pb, Cu, Mn and Zn levels were found highly associated to organic matter and sulfide fractions. The methods did not show significant statistical differences for the extraction of soluble and exchangeable cations and the metals associated to carbonate fraction. There are several significant correlations between heavy metals, which suggest their common origin. Rev. Biol. Trop. 58 (Suppl. 3): 129-140. Epub 2010 October 01.

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El Golfo de Cariaco es un ecosistema marino con mucha productividad primaria, lo que le confiere especial importancia ecológica y socioeconómica. Sin embargo, los desechos de las actividades antropogénicas son descargados directamente o arrastradas por las escorrentías. El objetivo de este estudio fue determinar la distribución de cadmio, cobre, plomo, manganeso, níquel y zinc en las fracciones geoquímica de los sedimentos superficiales, usando el método modificado de extracción secuencial de la Comunidad Europea (BCR). Las concentraciones de los metales fueron medidas por espectroscopía de absorción atómica. Además, se compararon los contenidos de metales intercambiables y asociados a los carbonatos determinados por el procedimiento BCR modificado con los determinados por el método de Campanella. La recolección de muestras se hizo en 12 estaciones del sector oriental del Golfo de Cariaco, Estado Sucre, específicamente en el sector conocido como el Saco, en junio 2007. Las metodologías aplicadas fueron evaluadas usando un material de referencia certificado de sedimentos marino (HISS - 1). Los resultados indicaron que los métodos proveen exactitud y precisión adecuadas para la extracción de metales. Las concentraciones totales (μg g-1) fueron, Cd: < límite de detección (LD)-5.0; Pb: 1.79- 60.41; Cu: no detectado (ND)-42.18; Zn: 25.13-104.57; Mn: 66.31-80.29 y Ni: 3.29-24.58. Cd, Cu, Ni y Pb excedieron en varias estaciones los límites que pueden afectar la biota, establecidos por la Guía de Evaluación de la Calidad de los Sedimentos de Canadá. El cadmio fue el metal identificado como el más móvil, teniendo las más altas concentraciones como intercambiable y asociado a las fracciones de carbonatos. Sin embargo, Pb, Cu, Mn y Zn mostraron su mayor abundancia en la fracción asociada a materia orgánica y azufre. Los métodos no presentan diferencias significativas para extraer la primera fracción. Se encontraron significantes correlaciones entre los metales pesados que sugieren su origen común.

Asunto(s)

Monitoreo del Ambiente/métodos , Sedimentos Geológicos/química , Metales Pesados/análisis , Contaminantes Químicos del Agua/análisis , Venezuela

RESUMEN

The Gulf of Cariaco is a marine ecosystem with high primary productivity, which gives it an ecological and socioeconomic importance. Nevertheless, anthropogenic activities around the Gulf produce wastes that are deposited directly or by runoff into the sediments, and consequently, increases concentrations of metals in this ecosystem. The objective of this study was to determine the distribution of cadmium, copper, lead, manganese, nickel and zinc in geochemical fractions of surface sediments, using modified BCR sequential extraction procedure. The concentrations were measured using flame atomic absorption spectroscopy. In addition, the contents of soluble and exchangeable metals associated to carbonate fractions, determined by BCR, were compared with those determined by the method of Campanella. Samples were collected in 12 stations during June 2007. The applied methodologies were evaluated with a certified reference material of marine sediments (HISS-1) and the results indicated that these methods provide adequate accuracy and precision for the extraction of metals. The total metal concentrations (microg g(-1)) were, Cd: < limit of detection (LD)-5.0; Pb: 1.79-60.41; Cu: no detected (ND)-42.18; Zn: 25.13-104.57; Mn: 66.31-80.29 and Ni: 3.29-24.58. Cd, Cu, Ni and Pb at several stations, exceeded the Canadian Sediment Quality Guidelines of the Lowest Effect Levels (LEL). Cadmium was identified as being the most mobile of the elements, having the highest concentrations in soluble and exchangeable cations and carbonates. However, Pb, Cu, Mn and Zn levels were found highly associated to organic matter and sulfide fractions. The methods did not show significant statistical differences for the extraction of soluble and exchangeable cations and the metals associated to carbonate fraction. There are several significant correlations between heavy metals, which suggest their common origin.

Asunto(s)

Monitoreo del Ambiente/métodos , Sedimentos Geológicos/química , Metales Pesados/análisis , Contaminantes Químicos del Agua/análisis , Venezuela

RESUMEN

Se determinó la concentración de grasa y proteína en el tejido muscular de 40 peces de cada una de las especies Pygocentrus cariba, Prochilodus mariae, Plagioscion squamosissimus, Piractus brachypomus e Hypostomus plecostomus, capturados en una laguna de inundación del rio Orinoco de medio utilizando redes de enmalle. Los contenidos de proteína y grasa se determinaron por los métodos de la Asociación de Químicos Analíticos Oficiales (AOAC), estimándose un promedio en la concentración de grasa para P. cariba de 0.30 ± 0.01 por ciento; 0.60 ± 0.01 por ciento para H. plecostomus; 0.65 ± 0.01 por ciento para P. mariae; 0.90 ± 0.01 por ciento para P squamosissimus y 1.55 ± 0.01 por ciento para P brachypomus. El promedio en la concentración de proteína fue de 19.60 ± 0.10 por ciento para P. mariae; 19.70 ± 0.13 por ciento para P. squamosissimus; 19.70 ± 0.09 por ciento para H. plecostomus; 19.80 ± 0.15 por ciento para P. cariba y 19.80 ± 0.15 por ciento para P. brachypomus. Un análisis de varianza (ANOVA) y prueba a posteriori de Duncan demostró diferencias estadísticamente significativas en el contenido de grasa entre especies, con los mayores valores correspondientes a P. brachypomus y P. squamosissimus y los menores a P. cariba. Los contenidos de proteína no presentaron diferencias significativas. Aparentemente las especies P. cariba, P. mariae, P squamosissimus, P. brachypomus y H. plecostomus, en general tienen un bajo contenido en grasa y una alta concentración de proteína, dependiendo sus concentraciones principalmente de la alimentación, época de reproducción y migración. El trabajo constituye un aporte al conocimiento de la composición química de estas especies, algunas de importancia comercial como P. squamosissimus, P brachypomus y P. mariae y otras ecológicamente importantes como P. cariba y H plecostomus.

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It was determined the concentration of fat and protein in the muscular tissue of 40 fish of each one of the species Pygocentrus cariba, Prochilodus mariae, Plagioscion squamosissimus, Piaractus brachypomus and Hypostomus plecostomus; captured in a lagoon flood of the middle Orinoco river using gillnets. The protein content and fat were determined by the methods of the Association of Official Analytical Chemistry (AOAC), being considered an average in the concentration of fat for P. cariba of 0.30 ± 0.01%; 0.60 ± 0.01% for H. plecostomus; 0.65 ± 0.01% for P. mariae; 0.90 ± 0.01% for P. squamosissimus and 1.55 ± 0.01% for P. brachypomus. The average in the protein concentration was of 19.60 ± 0.10% for P. mariae; 19.70 ± 0.13% for P. squamosissimus 19.70 ± 0.09% for H. plecostomus; 19.80 ± 0.15% for P. cariba and 19.80 ± 0.15% for P. brachypomus. A variance analysis (ANOVA) and a later test of Duncan it demonstrated differences statistically significant in the content of fat among species, with the bigger values of fat corresponding to P. brachypomus and P. squamosissimus and the smallest to P. cariba. The protein contents did not present significant differences. Seemingly the species P. cariba, P. mariae, P. squamosissimus, P. brachypomus and H. plecostomus, in general have a low content of fat and a high protein concentration, depending their concentrations mainly of the food, reproduction time and migration. This work constitutes a contribution to the knowledge of the chemical composition of these species, some of commercial importance as P. squamosissimus, P. brachypomus and P. mariae and other ecologically important as P. cariba and H. plecostomus.

Asunto(s)

Animales , Grasas , Peces , Composición de Alimentos , Proteínas

RESUMEN

Con el propósito de detectar alteraciones en el productivo ecosistemade la Laguna de Castillero (Caicara del Orinoco, municipio Cedeño del estado Bolívar, Venezuela), se presentan resultados de mediciones granulométricas y de las concentraciones de los metales pesados: Fe, Mn, Zn, Pb y Co realizadas en junio 2001 sobre los sedimentos superficiales y del tejido muscular de varias especies autóctonas de peces (Plasgiosium squamossimos, Pigocentrus cariba, Pheudoplastyloma fascia-tum, e Hypostomus spp realizadas en junio 2001. Utilizando técnica de espectrofotometría de absorción atómica con llama de aire acetileno, se determinó que, las concentraciones de metales más altas están representadas por manganeso, zinc y plomo. En la parte más interna de la laguna, el tipo de sedimento predominante es el lodo, constituyendo entre 30 por ciento y un 65 por ciento del material colectado por estación. Se encuentra, que esos niveles decrecen hacia la boca de la laguna, producto de la interacción de las corrientes de flujo/reflujo que lavan el sedimento y que se refleja en la mayor presencia de arena fina. El análisis estadístico de ANOVA muestra diferencias significativas entre las concentraciones de los metales en las estaciones, tipificadas por la presencia de promedios discrepantes. Los niveles promedios para los sedimentos superficiales de la zona son los siguientes: Fe (3365,44 ± 261,61), Mn (132,17 ± 25,46), Zn (253,04 ±86,48), Pb (17,02 ± 2,21) y Co (4,65 ± 0,76) µg/g. Similarmente, en el tejido muscular de los peces se cuantificaron las siguientes concentraciones: Fe entre (31,26 ± 0,06) y (68,36 ± 0,05);Mn entre (2,02 ± 0,05) y (4,16 ±0,03); Zn entre (19,09 ± 0,01) y (28,89 ± 0,01); Pb entre (0,38 ± 0,01) y (0,47 ± 0,03) µg/g. El análisis refleja una notable asociación entre los altos valores de concentraciones de metales y el tipo de sedimento, con un gradiente creciente hacia el sedimento tipo lodo. Se encuentran valores elevados en la concentración de Pb y Zn...

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To detected alterations in the productive ecosystem of the Castillero Lagoon (Caicara of the Orinoco, Cedeño Municipality, Bolivar State, Venezuela), results are presented for granulometric measurements and heavy metals concentrations: Fe, Mn, Zn, Pb and Co made in June 2001 on superface sediments and of the muscular tissue of several native species of fish (Plasgiosium squamossimos, Pigocentrus cariba, Pheudoplastyloma fasciatum, and Hypostomus spp. By using atomic absorption spectrophotometry with an air-acetylene flame, it was determined that the highest concentrations of metals are represented by manganese, zinc and lead. It was determined that the highest concentrations of metals are represented by manganese, zinc and lead. In the most internal part in the lagoon the type of predominant sediments is the mud, constituting among 30% and 65% of the material collected by station. Is that those levels fall toward the mouth of the lagoon, product of the interaction of the flow / reflux currents that washes the sediment and that is reflected in the biggest presence of fine sand. The statistical analysis of ANOVA shows significant differences among the concentrations of the metals in the stations, tipificated for the presence of different averages. The averages levels for the superficial sediments of the area are the following ones: Fe (3365.44 ± 261.61), Mn (132.17 ± 25.46), Zn (253.04 ± 86.48), Pb (17.02 ± 2.21) y Co (4.65 ± 0.76) µg/g. In similarly way, in the muscular tissue of the fish the following concentrations were quantified: Fe between (31.26 ± 0.06) and (68.36 ± 0.05); Mn between (2.02 ± 0.05) and (4.16 ± 0.03); Zn between (19.09 ± 0.01) and (28.89 ± 0.01); Pb between (0.38 ± 0.01) and (0.47 ± 0.03) µg/g. The analysis reflects a remarkable association between the high securities of concentrations of metals and the sediments type, with a growing gradient toward the sediments type mud. These are alarming values in concentration of Pb and Zn...

Asunto(s)

Animales , Contaminación Ambiental , Peces , Laguna Costera/análisis , Metales Pesados , Sedimentos , Oceanografía

RESUMEN

Se analizó por Espectrofotometría de Absorcion Atomica de llama el contenido de Fe, Mn, Cu, Cr, Ni, Zn, Cd y Pb en tejidos musculares de peces y crustáceos de la laguna de Unare, estado Anzoátegui, Venezuela. Adicionalmente, se determinaron los niveles en el material en suspension del agua y en el sedimento para detectar posibles impactos en el ecosistema. En el agua, las concentraciones medias de metales fueron bajos (0,104-0,53 µmol/L Fe; 0,004-0,06 µmol/L Mn; 0,002-0,028 µmol/L Zn; 0,004-0,012 µmol/L Cr; no detectado-0,011 µmol/LNi y no detectado- 0,001 µmol/L Cd). En el sedimento se evidencia intervención antropogénica con valores medios que decrecen Mn (516,37)>Zn (127,49)>Ni (52,41)>Cr (51,69)>Cu (41,13)>Pb (29)>Cd (1,51 µg/g) y que superan los niveles establecidos para sedimentos no contaminados. En los tejidos de los organismos se detectó la presencia de metales tóxicos como el plomo y cadmio que superan los 0,16 y 0,04 µg/g, res-pectivamente, al igual que el zinc que alcanza niveles elevados que sobrepasan 17 µg/g en la mayoría de las especies. Las pruebas estadísticas de ANOVA (P<0,05) indican discrepancias en las concentraciones metales en los tejidos por los diferentes géneros y especies, al igual que en los valores de los individuos de la misma especie (Cathorops spixii) que habitan dentro y fuera de la laguna. Los niveles son mayores en los habitantes del interior de la laguna evidenciando fenómenos de bioacumulación. La investigación confirman un progresivo deterioro ambiental de la laguna y de las especies ícticas de este ecosistema que son comercializadas por las poblaciones aledañas a la laguna, las cuales sustentan su economía de su explotación pesquera.

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The content of Fe, Mn, Cu, Cr, Ni, Zn, Cd and Pb in muscle tissues of fish and crustaceans from the Unare lagoon (Laguna de Unare) in the state of Anzoátegui, Venezuela, was analyzed by flame Atomic Absorption Spectrometry. The levels of these metals present in suspended material of the water and in sediments were also determined in order to detect possible impact on the ecosystem. The mean concentrations in the water were low (0.104-0.53 µmol/L Fe; 0.004-0.06 µmol/L Mn; 0.002-0.028 µmol/L Zn; 0.004-0.012 µmol/L Cr; undetectable-0.011 µmol/L Ni and undectable-0.001 µmol/L Cd). In the sediments, evidence was found of anthropogenic intervention with mean values in decreasing order of Mn (516.37) > Zn (127.49) > Ni (52.41) > Cr (51.69) > Cu (41.13) > Pb (29) > Cd (1.51 µg/g), all of which are greater than established levels for uncontaminated sediments. Toxic metals were detected in the examined organisms, such as lead and cadmium with levels above 0.16 and 0.04 µg/g, respectively, and zinc with levels greater than 17 µg/g in the majority of the species. ANOVA statistical tests (P < 0.05) show discrepancies in the concentrations or the metals in the tissues of the different genera and species, as well as in the values for individuals of the same species (Cathorops spixii) which live inside and outside of the lagoon. The levels are higher in those which live within the lagoon, which indicates bioaccumulation processes. This study confirms that the lagoon and its biota have suffered a progressive and important deterioration inasmuch as the neighboring population relies on the commercialization of the fish and crustaceans for their economic stability.

Asunto(s)

Animales , Crustáceos , Laguna Costera/análisis , Metales Pesados/efectos adversos , Peces/anatomía & histología , Medicina Veterinaria

RESUMEN

Se realizó un análisis de la concentración de algunos minerales como potasio, sodio, calcio, magnesio y hierro en el tejido muscular del morocoto Piaractus brachypomus del Orinoco medio en Venezuela, capturado en algunas lagunas de inundación con redes de enmalle. La concentración de estos minerales fue analizada mediante Absorción Atómica con llama de aire-acetileno y corrección de fondo de deuterio, utilizando un equipo Perkin Elmer 3100 acoplado con un automuestreador Perkin-Elmer AS-51. Se determinó un promedio 45,32 ± 0,52 µg/g en la concentración de hierro, 3497,48 ± 107,06 µg/g en la concentración de calcio, 1528,95 ± 29,25 µg/g en la concentración de magnesio, 3529,66 ± 65,24 µg/g en la concentración de sodio y 16488,90 ± 264,69 µg/g en la concentración de potasio. Un análisis de varianza (ANOVA) y prueba posteriori de Duncan, demostró que estas concentraciones presentaron diferencias significativas, con una mayor concentración de potasio, seguido del sodio y el calcio, y luego el magnesio y el hierro. Entre estos minerales las concentraciones de calcio y potasio presentaron correlación estadísticamente significativa. Los resultados constituyen un aporte al conocimiento de la composición química de P. brachypomus, uno de los peces de agua dulce más importante en el país desde el punto de vista comercial y en la acuacultura.

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An analysis of the concentrations of some mineral as potassium, sodium, calcium, magnesium and iron was made in the muscular tissue of the morocoto Piaractus brachypomus from the middle Orinoco River in Venezuela, captured in some flood lagoons with gillnet. The concentration of these minerals was analyzed by Atomic Absorption with flame of air-acetylene and correction of deuterium, using a team Perkin Elmer 3100 coupled with an autosampler Perkin-Elmer ACE-51. An average of 45.32 ± 0.52 µg/g was determined in the iron concentration, 3497.48 ± 107.06 µg/g in the concentration of calcium, 1528.95 ± 29.25 µg/g in the concentration of magnesium, 3529.66 ± 65.24 µg/g in the concentration of sodium and 16488.90 ± 264.69 µg/g in the concentration of potassium. A variance analysis (ANOVA) and Duncan test later, demonstrated that these concentrations presented significant differences, with a bigger concentration of potassium, followed by the sodium and the calcium, and then the magnesium and the iron. Among these minerals the concentrations of calcium and potassium presented correlation statistically significant. The results constitute a contribution to the knowledge of the chemical composition of P. brachypomus, one of the freshwater fish most important in the country from the commercial point of view and in the aquaculture.

Asunto(s)

Animales , Espectrofotometría Atómica/métodos , Agua Dulce/análisis , Peces , Minerales/análisis , Minerales/síntesis química