Impacto del COVID-19 en la esperanza de vida en los municipios de los estados del noreste de México / COVID-19 impact on life expectancy among municipalities of Northeastern states of Mexico

RESUMEN La mortalidad causada por COVID-19 en México se ha situado entre las más altas del mundo, por lo que es de interés epidemiológico estudiar su impacto respecto a la esperanza de vida (EV). El objetivo del presente trabajo fue analizar el impacto de la pandemia por COVID-19 en la esperanza de vida, comparando datos de 2019 y 2020, y evaluando su efecto por densidad poblacional de los municipios de los estados del noreste de México. La información sobre mortalidad para 2019 y 2020 se obtuvo de la Secretaría de Salud, y la demográfica del Consejo Nacional de Población. Se construyeron tablas de vida mediante el método actuarial estándar; se calcularon percentiles ≤ 25 y ≥ 75 de la diferencia en la EV; se evaluó la relación entre el tamaño de la población de los municipios y la magnitud de la diferencia en la pérdida de años en la EV. La pandemia por COVID-19 impactó en la EV en los estados del noreste de México, con gran heterogeneidad al interior en cada uno de ellos. La pérdida en años en promedio fue, para Coahuila de 5.4, Nuevo León 4.1 y Tamaulipas 4.9. Los municipios del percentil ≥ 75 mostraron una pérdida promedio de 9.2 años y los del percentil ≤ 25 de -0.35 años. La diferencia en la pérdida en años de EV, entre 2019 y 2020, se vio influenciada por el tamaño de la población, tendiendo a ser mayor en aquellos con mayor densidad demográfica, sin ser el único factor determinante.

ABSTRACT COVID-19 mortality in Mexico is among the highest in the world. Therefore, it is of epidemiologic interest to study its impact on life expectancy. The aim of the present paper was to analyze the impact of the COVID-19 pandemic on life expectancy through a comparison of data from 2019 and 2020. Specifically, the effect of population density in municipalities of Northeastern Mexican states. Information regarding 2019 and 2020 mortality rates for was obtained from the Ministry of Health, and demographics from the National Population Council. Life tables were constructed using the standard actuarial method. Percentiles ≤ 25 and ≥ 75 of the difference in life expectancy in the period were calculated. The relationship between the size of the population of the municipalities and the magnitude of the difference in life expectancy loss of years was evaluated. COVID-19 pandemic impacted on life expectancy with great heterogeneity in each of the northeastern states of Mexico. The loss in years in average life expectancy was 5.4 for Coahuila, 4.1 for Nuevo Leon and 4.9 for Tamaulipas. Municipalities above the ≥ 75th percentile showed an average loss of 9.2 years. Those in the lower than ≤ 25th percentile showed a decrease, of -0.35 years. The difference in the loss of life expectancy during 2019 and 2020 was influenced by population size, tending to be greater in those municipalities with higher population density, but was not the only determining factor.

Effect of COVID-19 mortality on life expectancy in municipalities of Mexico. Comparison between 2019 and 2020.

BACKGROUND: Life expectancy (LE) is an indicator related to medical, demographic, social and geographic conditions. OBJECTIVES: To analyze the effect of the COVID-19 pandemic on LE and of its distribution according to sociodemographic variables in municipalities of Mexico. METHODS: Information on mortality was collected from data published by the Ministry of Health, and demographic information, from the 2020 Population and Housing Census. LE was calculated according to the standard actuarial method. A risk analysis was carried out between expected years of life lost and the size of the economically active population, years of education and indigenous-speaking population. RESULTS: In 2020, there was a nation-wide average drop of 4.7 years in LE, but its distribution was heterogeneous at the municipal level, with extreme values of -2.8 years and 12.6 years. The risk analysis showed an inverse relationship between sociodemographic variables and expected years of life lost, except for the indigenous-speaking population. CONCLUSIONS: The impact of the COVID-19 pandemic on LE in Mexico was significant and was influenced by the analyzed sociodemographic variables, particularly by the municipalities' population size.

ANTECEDENTES: La esperanza de vida es un indicador relacionado con condiciones médicas, demográficas, sociales y geográficas. OBJETIVOS: Analizar el efecto de la pandemia de COVID-19 en la esperanza de vida y de su distribución según variables sociodemográficas en municipios de México. MATERIAL Y MÉTODOS: Se recabó información sobre mortalidad de la Secretaría de Salud, así como información demográfica del Censo de Población y Vivienda de 2020. La esperanza de vida se calculó conforme el método actuarial estándar. Se realizó análisis de riesgo entre la pérdida de la esperanza de vida en años y el tamaño de la población, población económicamente activa, años de escolaridad y población de habla indígena. RESULTADOS: En 2020 se registró una caída promedio de 4.7 años en la esperanza de vida a nivel nacional, pero su distribución fue heterogénea en los municipios, con valores extremos de −2.8 años y 12.6 años. El análisis de riesgo mostró una relación inversa entre las variables sociodemográficas y la pérdida de años de esperanza de vida, con excepción de la población de habla indígena. CONCLUSIONES: El impacto de la pandemia de COVID-19 en la esperanza de vida en México fue significativo, matizado por las variables sociodemográficas analizadas, particularmente por el tamaño de la población de los municipios.

Efecto de la mortalidad por COVID-19 en la esperanza de vida en los municipios de México. Comparación 2019 y 2020 / Effect of COVID-19 mortality on life expectancy in municipalities of Mexico. Comparison between 2019 and 2020

Resumen Antecedentes: La esperanza de vida es un indicador relacionado con condiciones médicas, demográficas, sociales y geográficas. Objetivos: Analizar el efecto de la pandemia de COVID-19 en la esperanza de vida y de su distribución según variables sociodemográficas en municipios de México. Material y métodos: Se recabó información sobre mortalidad de la Secretaría de Salud, así como información demográfica del Censo de Población y Vivienda de 2020. La esperanza de vida se calculó conforme el método actuarial estándar. Se realizó análisis de riesgo entre la pérdida de la esperanza de vida en años y el tamaño de la población, población económicamente activa, años de escolaridad y población de habla indígena. Resultados: En 2020 se registró una caída promedio de 4.7 años en la esperanza de vida a nivel nacional, pero su distribución fue heterogénea en los municipios, con valores extremos de −2.8 años y 12.6 años. El análisis de riesgo mostró una relación inversa entre las variables sociodemográficas y la pérdida de años de esperanza de vida, con excepción de la población de habla indígena. Conclusiones: El impacto de la pandemia de COVID-19 en la esperanza de vida en México fue significativo, matizado por las variables sociodemográficas analizadas, particularmente por el tamaño de la población de los municipios.

Abstract Background: Life expectancy (LE) is an indicator related to medical, demographic, social and geographic conditions. Objectives: To analyze the effect of the COVID-19 pandemic on LE and of its distribution according to sociodemographic variables in municipalities of Mexico. Methods: Information on mortality was collected from data published by the Ministry of Health, and demographic information from the 2020 Population and Housing Census. LE was calculated according to the standard actuarial method. A risk analysis was carried out between expected years of life lost and the size of the population, economically active population, years of education and indigenous-speaking population. Results: In 2020, there was a nation-wide average drop of 4.7 years in LE, but its distribution was heterogeneous at the municipal level, with extreme values of -2.8 years and 12.6 years. The risk analysis showed an inverse relationship between sociodemographic variables and expected years of life lost, except for the indigenous-speaking population. Conclusions: The impact of the COVID-19 pandemic on LE in Mexico was significant, and was influenced by the analyzed sociodemographic variables, particularly by the municipalities' population size.

Modelación espacial bayesiana de la estructura de los hogares y la fecundidad en municipios de México

El trabajo busca modelar el efecto de diferentes patrones de composición de hogares sobre los niveles observados de fecundidad en los municipios de México al año 2020, se trata de una investigación de tipo cuantitativo de cohorte transversal basada en la aplicación de métodos bayesianos espaciales. La hipótesis sostiene que la presencia de un mayor porcentaje de hogares familiares debería impactar en mayores tasas de fecundidad municipales. La metodología comprende la implementación de dos modelos gaussianos latentes. Un modelo nulo busca determinar si los patrones observados de fecundidad se asocian a algún mecanismo sociodemográfico o, al contrario, surgieron aleatoriamente, y otro modelo con covariables, cuyo objetivo es replicar el comportamiento de la fecundidad evaluando las consecuencias de la proporción de hogares nucleares, ampliados y compuestos presentes en los municipios. Los resultados obtenidos a partir de la estimación del modelo nulo confirmaron la existencia de una relación directa entre el aumento del índice de hogares nucleares y ampliados y el de la fecundidad municipal. Sin embargo, se puede concluir que el nivel alcanzado de fecundidad de reemplazo es producto de marcadas diferencias entre municipios, originadas por la presencia de una tipología heterogénea de hogares inmersos en contextos geográficos, sociales y culturales dispares.

This paper seeks to model the effect that different patterns of household composition have on the observed levels of fertility in the municipalities of Mexico in the year 2020; it is a quantitative cross-sectional cohort research based on the application of spatial Bayesian methods. The hypothesis is that the presence of a higher percentage of family households should have an impact on higher municipal fertility rates. The methodology involves the implementation of two latent Gaussian models. One null model, which seeks to determine whether the observed fertility patterns were generated by some socio-demographic mechanism or, on the contrary, arose randomly, and two, a model with covariates whose objective is to replicate the behavior of fertility by evaluating the effect of the proportion of nuclear, extended and compound households present in municipalities. The results obtained from estimation of null model confirm the existence of a direct relationship between increase in the proportion of nuclear and extended households and the increase of municipal fertility. However, it can be concluded that the level of replacement fertility reached by Mexico in the year 2020 is the product of marked differences between municipalities; differences originated by the presence of a heterogeneous typology of households immersed in disparate geographic, social and cultural contexts.

Bayesian spatial modelling of contraception effects on fertility in Mexican municipalities in 2020.

The prevalence and use of contraceptive methods is an essential element to explain the behaviour of fertility and population growth. The objective of this study was to analyse the spatial correlation between the use of contraceptive methods in women of childbearing age and fertility levels observed in Mexico's municipalities in 2020. Data on contraceptive use are from the National Survey of Demographic Dynamics (ENADID) 2018, while fertility rates were estimated from vital statistics and population census data. Three Bayesian spatial models including fixed effects, random effects and spatial effects were employed. The models were estimated using the integral nested Laplace approximation (INLA) package available in the R language. The results reveal the existence of important regional inequalities associated with the use and prevalence of contraceptive methods, which generate marked differences in observed levels of fertility between municipalities.

Phylogeography of the neotropical epiphytic orchid, genus Dracula.

The tropical Andes constitute a natural barrier between the Pacific Ocean and the Atlantic; in these mountains, are a great variety of Ecosystems, defined by factors such as orography, winds, humidity, temperature, among others. Some of these Ecosystems have different environmental conditions from tropical ones. In them, there is a great Biodiversity, in some cases endemic and associated with relatively small geographic areas. An example of this biodiversity is the orchids of the genus Dracula, about which discussions are currently generated due to the difficulty in classifying their members. The present work shows a study where DNA was isolated and sequenced from plant samples obtained from 52 species of orchids of the genus Dracula, which were analyzed using the MEGA7 software. Phylogenetic analysis of the DNA sequences showed a well-resolved topology that reflects a geographical pattern of several major clades of the Pacific and Atlantic watersheds. Geophysical conditions of the Andes have generated greater biodiversity of the genus Dracula on the side of the Pacific. Although the species Dracula cordobae and alessandroi reported on both sides of the study site belong to the same clade and show limited mobility through the drier area to the South of the mountain range.

Disfunción tiroidea en pacientes con diabetes mellitus tipo 2 / Thyroid Dysfunction in Patients with Type 2 Diabetes Mellitus

RESUMEN Fundamento la disfunción tiroidea se encuentra con frecuencia entre los pacientes con diabetes mellitus tipo 2, esa proporción aumenta y es el hipotiroidismo la disfunción más frecuente. Objetivo determinar el comportamiento de la disfunción tiroidea en pacientes con diabetes mellitus tipo 2 en el Hospital General Universitario Dr. Gustavo Aldereguía Lima de Cienfuegos. Método: se realizó un estudio de corte transversal, entre el 1 de enero y el 31 de diciembre de 2018, en el Servicio Ambulatorio de personas con diabetes mellitus del Hospital General Universitario Dr. Gustavo Aldereguía Lima de Cienfuegos. Se estudiaron un total de 210 pacientes. Las variables analizadas fueron: edad, sexo, antecedentes patológicos personales, antecedentes patológicos familiares, tiempo de diagnóstico, presencia de disfunción tiroidea y tipo de disfuncióntiroidea. Se calculó el intervalo de confianza del 95 %. Para efectuar las comparaciones entre las frecuencias, se utilizó el test de Fisher. Resultados el 32,4% de los pacientes estudiados presentaron disfunción tiroidea, de ellos un 23,3 % fueron del sexo femenino en las cuales predominó el hipotiroidismo subclínico lo que representó el 42,6 %. El grupo de edad entre 40 y 49 años fue el más representativo en el 9,1% de los pacientes. La presencia de antecedentes patológicos familiares de diabetes mellitus tipo 2 y de disfunción tiroidea fue del 30 y el 19,5% respectivamente. Conclusión: la prevalencia de disfunción tiroidea es similar a la encontrada en algunos estudios previos, siendo más representativa en la quinta década de la vida, es más frecuente en el sexo femenino y el hipotiroidismo subclínico fue el que más predominó.

ABSTRACT Background: thyroid dysfunction is frequently found among patients with type 2 diabetes mellitus, this proportion increases, being hypothyroidism the most frequent. Objective: to determine the behavior of thyroid dysfunction in patients with type 2 diabetes mellitus at the Dr. Gustavo Aldereguía Lima University General Hospital in Cienfuegos. Method: a cross-sectional study was carried out between January the 1st and December the 31st, 2018, in the Outpatient Service of people with diabetes mellitus in the Dr. Gustavo Aldereguía Lima General University Hospital of Cienfuegos. A total of 210 patients were studied. The variables analyzed were: age, sex, personal pathological history, family pathological history, time of diagnosis, presence of thyroid dysfunction and type of thyroid dysfunction. The 95 % confidence interval was calculated. The Fisher's test was used to compare between frequencies. Results: the 32.4 % of the patients studied had thyroid dysfunction, from which 23.3 % were female, in which subclinical hypothyroidism predominated, representing the 42.6 %. The age group between 40 and 49 years was the most representative with the 9.1% of the patients. The presence of a family pathological history of type 2 diabetes mellitus and thyroid dysfunction was the 30 % and the 19.5 %, respectively. Conclusion: the prevalence of thyroid dysfunction is similar to that found in some previous studies, being more representative in the 5th decade of life, it is more frequent in the female sex and the subclinical hypothyroidism was the most predominant.

Inspection of real and imputed genotypes reveled 76 SNPs associated to rear udder height in Holstein cattle.

OBJECTIVE: This paper presents the obtained result of a study that realizes to associate a set of real and imputed single nucleotide polymorphisms (SNP) genotypes to the rear udder height in Holstein cows. MATERIALS AND METHODS: Forty-six Holstein cows from an arid zone of Mexico were phenotyped and genotyped for this study. Blood samples were used for DNA extraction, genotyping was performed with the Illumina BovineLD Bead chip which interrogates 6,912 SNPs genome-wide, and imputation was performed using the Findhap software. After QC filters, a total of 22,251 high quality and informative SNPs were inspected. RESULTS: The results showed the detection of 76 significant SNPs throughout the complete genome. Significant SNPs fall inside 111 Quantitative Loci Traits related to protein percentage, milk yield, and fat, among others, in chromosomes 1, 2, 3, 5, 6, 9, 10, 11, 12, 13, 19, 20, 21, 23, 26, 27, and 29. Similarly, results confirm that a genotype imputation is a convenient option for genome-wide covering when selecting economic traits with low-density real SNP panels. CONCLUSION: This study contributes to establishing a low-cost and profitable strategy for applying genomic selection in developing countries.

Benefit of oxytocin released by cervix stimulation in Mexican Holstein cattle.

OBJECTIVE: The aim of this research is to investigate the relationship level of oxytocin released and the tactile stimulation of the cervix in Holstein cattle from the northwestern arid regions in México. MATERIALS AND METHODS: The cervixes of 10 Holstein Friesian dairy cows in mid-lactation were manually stimulated for 60 sec. Oxytocin released in the blood was analyzed before and after stimulation. The enzyme-linked immunosorbent assay was used in the analysis to make oxytocin detectable by spectrometry techniques and by converting the luminescence absorbance of each sample into pg per mol. RESULTS: The study revealed that tactile stimulation of the cervix increased oxytocin levels. The highest increase in oxytocin level was 10,940.8222 pg/mol, while the lowest increase in oxytocin level was 1,830.94254 pg/mol. Besides, the milk production by tactile stimulation of the cervix had a higher milk yield and a p-value of 9.4 × 10-4 (p < 0.05) in comparison to the monthly average without tactile stimulation. CONCLUSION: Tactile stimulation of the cervix activates the Ferguson reflex and increases the oxytocin released in the blood and increases the milk released from the alveolar glands.

Modelación espacial bayesiana del riesgo de embarazo adolescente a través de la aproximación anidada integrada de Laplace en Chiapas, 2015 / Bayesian spatial modeling of adolescent pregnancy risk through integrated nested Laplace approximation in Chiapas, 2015

Resumen El objetivo del trabajo es analizar la distribución espacial de la fecundidad adolescente municipal en Chiapas durante 2015. Método: a partir de la utilización de modelos aditivos estructurales estimados mediante la aproximación anidada integrada de Laplace. Resultados: Un primer modelo identifica los patrones espaciales no aleatorios de la fecundidad, mientras un segundo modelo analiza el efecto que ejercen cofactores como: pobreza, marginación y analfabetismo, sobre la distribución espacial de la fecundidad adolescente. Discusión: Los resultados parecen confirmar que los espacios donde se registran mayores índices de marginación, analfabetismo y pobreza incrementan el riesgo de configurar un clúster donde las tasas de fecundidad adolescente observadas son en promedio mayores que las presentadas por los municipios vecinos.

Abstract The objective of the study is to analyze the spatial distribution of adolescent municipal fertility in Chiapas during 2015. Method: from the use of estimated structural additive models through the integrated nested approach of Laplace. Results: A first model identifies the non-random spatial patterns of fertility, while a second model analyzes the effect of cofactors such as poverty, marginalization and illiteracy on the spatial distribution of adolescent fertility. Discussion: The results seem to confirm that the spaces where higher rates of marginalization, illiteracy and poverty are registered increase the risk of setting up a cluster where the adolescent fertility rates observed are on average higher than those presented by neighboring municipalities.

Larval development of Evermannia zosterura (Perciformes: Gobiidae).

Gobiidae is the most specious fish family in the world with almost 2 000 species, however only 11% of them have been described for their larval stages. The entire life cycle information is essential to understand the biology and ecology of this important fish group. Previous studies on zooplankton samples from Ensenada de La Paz, México, have shown the presence of several Gobiidae larvae and juveniles which were identified as Evermania zosterura. The main objective of this work was to describe the larval stages of this species, widely distributed in the Eastern tropical Pacific. The development of E. zosterura larvae was described based on 66 specimens. A total of 53 specimens were used to describe morphometrics and pigmentation patterns, while 13 specimens were cleared and stained, to obtain meristic characteristics. Cleared specimens had 30 to 31 total vertebrae; dorsal-fin elements: IV; 1, 13-14, anal-fin elements: 1, 13-14, and most had pterygiophore formula 4-111100. The combination of these characteristics confirmed these specimens as E. zosterura. The pigment pattern is similar throughout ontogeny. Larvae are characterized by having three to five dendritic melanophores along the post-anal ventral margin, four to nine smaller melanophores along the ventral margin between the isthmus and anus, and one on the midpoint of the dorsal margin of the tail. There is one small pigment spot on the angle of the jaw, and other on the tip of lower lip. There is an elongated internal pigment under the notochord, between the head and gas bladder. Notochord flexion starts near 3.5mm BL and ends at 4.6mm BL; transformalion to the juvenile stage is at about 13.6mm BL. Our conclusion is that the most useful characters to distinguish this species early-larval stages from those of similar species in the area, are the number of myomeres, the large melanophores (approximately uniformly in size) on the post anal ventral margin, and the elongate internal pigment under the notochord, anterior to the gas bladder.

Larval development of Evermannia zosterura (Perciformes: Gobiidae)

Gobiidae is the most specious fish family in the world with almost 2 000 species, however only 11% of them have been described for their larval stages. The entire life cycle information is essential to understand the biology and ecology of this important fish group. Previous studies on zooplankton samples from Ensenada de La Paz, México, have shown the presence of several Gobiidae larvae and juveniles which were identified as Evermania zosterura. The main objective of this work was to describe the larval stages of this species, widely distributed in the Eastern tropical Pacific. The development of E. zosterura larvae was described based on 66 specimens. A total of 53 specimens were used to describe morphometrics and pigmentation patterns, while 13 specimens were cleared and stained, to obtain meristic characteristics. Cleared specimens had 30 to 31 total vertebrae; dorsal-fin elements: IV; I, 13-14, anal-fin elements: I, 13-14, and most had pterygiophore formula 4-111100. The combination of these characteristics confirmed these specimens as E. zosterura. The pigment pattern is similar throughout ontogeny. Larvae are characterized by having three to five dendritic melanophores along the post-anal ventral margin, four to nine smaller melanophores along the ventral margin between the isthmus and anus, and one on the midpoint of the dorsal margin of the tail. There is one small pigment spot on the angle of the jaw, and other on the tip of lower lip. There is an elongated internal pigment under the notochord, between the head and gas bladder. Notochord flexion starts near 3.5mm BL and ends at 4.6mm BL; transformation to the juvenile stage is at about 13.6mm BL. Our conclusion is that the most useful characters to distinguish this species early-larval stages from those of similar species in the area, are the number of myomeres, the large melanophores (approximately uniformly in size) on the post anal ventral margin, and the elongate internal pigment under the notochord, anterior to the gas bladder. Rev. Biol. Trop. 62 (2): 603-610. Epub 2014 June 01.

La familia Gobiidae es la más diversa de los peces en el mundo con casi 2 000 especies, sin embargo solo el 11% de ellos han sido descritos en sus estadios larvarios. El conocimiento del ciclo de vida completo es esencial para entender la biología y ecología de este importante grupo de peces. Muestras de zooplancton obtenidas de la Ensenada de La Paz, México, mostraron la presencia de varias larvas y juveniles de Gobiidae, las cuales fueron identificadas como Evermania zosterura. El principal objetivo de este trabajo fue describir los estadios larvarios de esta especie ampliamente distribuida en el Pacífico tropical Oriental. Se describió el desarrollo larvario de E. zosterura con base en 66 especímenes recolectados en la Ensenada de La Paz, México. Sólo 53 especímenes se usaron para describir la morfometría y el patrón de pigmentación, mientras que 13 ejemplares transparentados y teñidos se utilizaron para obtener las características merísticas. Los especímenes transparentados tuvieron de 30 a 31 vertebras totales; los elementos de las aletas dorsales fueron IV; I, 13-14, los de la aleta anal I, 13-14 y la mayoría tuvo una formula pterigiofórica de 4-111100. La combinación de estas características, confirmó que pertenecen a E. zosterura. El patrón de pigmentación es muy similar a lo largo del desarrollo. Las larvas se caracterizan por tener de tres a cinco melanóforos de tipo dendrítico sobre el borde ventral post-anal, de cuatro a nueve melanóforos más pequeños sobre el borde ventral pre-anal, entre el istmo y el ano, otro melanóforo se presenta a la mitad del margen dorsal de la cola. Hay una pequeña mancha de pigmento en el ángulo de la maxila y otra en la punta del labio inferior. Hay un pigmento interno alargado por debajo de la notocorda, entre la cabeza y la vejiga natatoria. La flexión de la notocorda se inicia a los 3.5mm BL y termina a los 4.6mm BL; la transformación al estadio juvenil es cercana a los 13.6mm BL. Nuestra conclusión es que los caracteres más importantes para distinguir las larvas de esta especie de aquellas similares en el área son el número de miómeros, los melanóforos grandes (aproximadamente iguales en tamaño) en el margen ventral post-anal y el pigmento interno alargado debajo de la notocorda, anterior a la vejiga gaseosa.

Actividad antibacteriana y antifúngica de extractos de algas marinas venezolanas / Antibacterial and antifungal activity from extracts of Venezuelan marine algae

En este trabajo se evaluaron las propiedades bioactivas antibacterianas y antimicóticas de 33 extractos (etanol, diclorometano, hexano) obtenidos de 11 especies de algas marinas recolectadas en las localidades de San Juan de Los Cayos y Chichiriviche, Estado Falcón, Venezuela. La actividad antibiótica y antimicótica de los extractos se evaluó mediante la aparición de halos de inhibición contra bacterias Gram positivas (Staphylococcus aureus), Gram negativas (Pseudomona aeruginosa, Klebsiella pneumoniae, Escherichia coli) y el hongo Candida albicans. De los 33 extractos ensayados sólo 17 presentaron actividad antibacteriana (5 con etanol, 6 con diclorometano y 6 con hexano), resultando activos 14 frente a las especies Gram(-) y 4 contra la especie Gram(+). Las especies algales que mostraron actividad antibacteriana fueron: Acanthophora sp., Bryothamnion triquetrum, Gracilaria sp., Gelidium sp., Caulerpa mexicana, Caulerpa sp., Caulerpa spp., Halimeda incrassata, Ulva sp., Codium decorticatum, Sargassum sp. Ninguno de los extractos de algas ensayados presentó actividad antimicótica sobre Cándida albicans. Los resultados obtenidos permiten concluir que las algas de la costa occidental de Venezuela, presentan compuestos bioactivos con actividad antibacteriana.

This study assessed the antibacterial and antifungal properties of 33 extracts (ethanol, dichloromethane, hexane) from 11 species of marine algae collected in the villages of San Juan de Los Cayos and Chichiriviche, Estado Falcon, Venezuela. The antibiotics and antifungal activity of extracts was evaluated by the appearance of halos of inhibition against gram-positive bacteria (Staphylococcus aureus), Gram negative (Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli) and the fungus Candida albicans. Of the 33 tested extracts showed antibacterial activity only 17 (5 with ethanol, 6 and 6 with dichloromethane-hexane), resulting assets compared to 14 species Gram(-) and 4 against the kind Gram(+). The algae species that showed antibacterial activity were: Acanthophora sp., Bryothamnion triquetrum, Gracilaria sp., Gelidium sp., Caulerpa mexicana, Caulerpa sp., Caulerpa spp., Halimeda incrassata, Ulva sp., Codium decorticatum, Sargassum sp.. None of the tested extracts from algae introduced antifungal activity on Candida albicans. The findings suggest that the algae on the west coast in Venezuela have bioactive compounds with antibacterial activity.

Producción de biomasa de Saccharomyces cerevisiae y Candida utilis usando residuos de pulpa de Coffea arabica L

Los avances en biotecnología industrial ofrecen oportunidades potenciales para la utilización económica de residuos agro-industriales tales como la pulpa de café, material mucilaginoso, fibroso (producto secundario) obtenido durante el proceso húmedo o seco del beneficio de las cerezas de café. El propósito de este trabajo fue utilizar los residuos de la pulpa de café, rico en materia orgánica, como sustrato para la producción de biomasa de levaduras por procesos de fermentación aeróbica. Los residuos de café se sometieron a hidrólisis con una solución de ácido sulfúrico al 2%, en una relación 10:1 (líquido:sólido), con un tamaño de partícula ≤ 2 mm., operando a presión atmosférica, ebullición a reflujo, durante 4 horas. El extracto ácido se filtró y se ajustó a pH 4,5 y luego se esterilizó a 120 ºC por 15 minutos. La fermentación se realizó con Saccharomyces cerevisiae y Candida utilis, medio de producción extracto de café enriquecido con sales nutritivas. Se formularon diferentes medios de producción (1,2,3 y 4), siendo el N°3, enriquecido con extracto de café hidrolizado, 1L; urea, 3g/L; fosfato ácido de potasio, 2g/L; extracto de malta, 1,3g/L y melaza, 30g/L, el cual aportó los mejores resultados. El tiempo total de fermentación fue de 8 horas. Se obtuvo 10g/L de biomasa con un incremento proteico de 7,39 a 42,5%. Se puede concluir que la pulpa de café constituye un sustrato adecuado para obtener biomasa o proteína unicelular, que podría ser destinada como suplemento en formulaciones para alimentación animal.

The advances in industrial biotechnology offer potential opportunities for the economic use of agro-industrial remainders such as the coffee pulp, mucilagenous, fibrous material (secondary product) obtained during the humid or dry process of the benefit of the coffee cherries. The intention of this work was to use the remainders of the pulp of coffee, rich in organic matter, like substrate for the production of biomass of leavenings by processes of aerobic fermentation. The coffee remainders were put under hydrolysis with a sulfuric acid solution to 2%, in a 10:1 relation (liquid: solid), with a size of particle ≤ 2 mm, operating to atmospheric pressure, boiling to ebb tide, during 4 hours. The acid extract filtered and it adjusted to pH 4,5 and then it sterilize to 120 ºC by 15 minutes. The fermentation was made with Saccharomyces cerevisiae and Candida utilis, the production means: extract of coffee enriched with nutritious salts. Different means from production were formulated (1,2,3 and 4), being the N°3, enriched with extract of hydrolyzed coffee, 1L; urea, 3g/L; acid potassium phosphate, 2g/L; extract of Malta, 1,3g/L and molasses, 30g/L, which contributed the best results. The total time of fermentation was of 8 hours. 10g/L of biomass with a protein increase from 7.39 to 42.5% was obtained. It is possible to be concluded that the coffee pulp constitutes an suitable substrate to obtain biomass or unicellular protein, that could be destined like supplement in formulations for feeding animal.

Expression of cholera toxin under non-AKI conditions in Vibrio cholerae El Tor induced by increasing the exposed surface of cultures.

The regulatory systems controlling expression of the ctxAB genes encoding cholera toxin (CT) in the classical and El Tor biotypes of pathogenic Vibrio cholerae have been characterized and found to be almost identical. Notwithstanding this, special in vitro conditions, called AKI conditions, are required for El Tor bacteria to produce CT. The AKI conditions involve biphasic cultures. In phase 1 the organism is grown in a still tube for 4 h. In phase 2 the medium is poured into a flask to continue growth with shaking. Virtually no expression of CT occurs if this protocol is not followed. Here we demonstrated that CT expression takes place in single-phase still cultures if the volume-to-surface-area ratio is decreased, both under air and under an inert atmosphere. The expression of key genes involved in the regulation of CT production was analyzed, and we found that the expression pattern closely resembles the in vivo expression pattern.

Transcriptional regulation of Pseudomonas aeruginosa rhlR, encoding a quorum-sensing regulatory protein.

The Pseudomonas aeruginosa rhlR gene encodes the transcriptional regulator RhlR which has a central role in the quorum-sensing response. Different gene products involved in bacterial pathogenesis are regulated at the transcriptional level by two quorum-sensing response systems, Las and Rhl. The expression of rhlR has been reported to be under the control of the Las system, but its transcriptional regulation has not been studied in detail. Here, the rhlR promoter region has been characterized and shown to present four different transcription start sites, two of which are included in the upstream gene (rhlB) coding region. It was found that rhlR expression is not only dependent on LasR but also on different regulatory proteins such as Vfr and RhlR itself, and also on the alternative sigma factor sigma(54). It is reported that rhlR expression is partially LasR-independent under certain culture conditions and is strongly influenced by environmental factors.

Distribution and abundance of Syacium ovale larvae (Pleuronectiformes: Paralichthyidae) in the Gulf of California

The spawning season of the tonguefish Syacium ovale (Günter 1864) was determined by an analysis of the distribution of preflexion stage larvae in the Gulf of California. The larvae were collected during eight oceanographic surveys between 1984 and 1987. The spawning of this species starts in early summer and ends at the beginning of fall, with the highest reproductive activity in mid summer. The central and southern regions of the Gulf are the most important reproductive area. Spawning is associated with high sea surface temperatures and low plankton biomass, both of which are characteristics of the tropical current that invades the study area during summer.

The Pseudomonas aeruginosa rhlAB operon is not expressed during the logarithmic phase of growth even in the presence of its activator RhlR and the autoinducer N-butyryl-homoserine lactone.

The Pseudomonas aeruginosa rhlAB operon encodes the enzyme rhamnosyltransferase 1, which produces the biosurfactant mono-rhamnolipid; rhlAB induction is dependent on the quorum-sensing transcription activator RhlR complexed with the autoinducer N-butyryl-homoserine lactone (C(4)-HSL). In this work we studied rhlAB induction in a P. aeruginosa and Escherichia coli background. We found that, in both bacteria, its expression is not induced during the logarithmic phase of growth even in the presence of RhlR and C(4)-HSL. Additionally, we found that rhlAB expression is partially sigma(s) dependent.

Distribution and abundance of Syacium ovale larvae (Pleuronectiformes: Paralichthyidae) in the Gulf of California.

The spawning season of the tonguefish Syacium ovale (Günter 1864) was determined by an analysis of the distribution of preflexion stage larvae in the Gulf of California. The larvae were collected during eight oceanographic surveys between 1984 and 1987. The spawning of this species starts in early summer and ends at the beginning of fall, with the highest reproductive activity in mid summer. The central and southern regions of the Gulf are the most important reproductive area. Spawning is associated with high sea surface temperatures and low plankton biomass, both of which are characteristics of the tropical current that invades the study area during summer.