Hidrobiológica (E-Journal)
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Screening for anticoagulant substances in some marine macroalgae
Get PDFThe coagulation disorders have increased in the last decades and no new substances had been discovered that could regulate this illness. This fact makes the discovery of new anticoagulant substances a priority issue in research. Forty nine seaweed species collected off shore of several localities of Gulf of Mexico and Mexican Caribbean sea were screened in order to detect anticoagulant activity in both intrinsic and extrinsic pathways of clot formation. Standardized plasma coagulation tests (thrombin and prothrombin time) were used. Heparin, a sulphated glycosaminoglycan wide used in oral anticoagulant therapy, was used as reference in both proofs. The results showed that four species presented potent anticoagulant activity same as heparin in the two pathways: Anadyomene stellata, Caulerpa cupressoides (Chlorophyta), Lobophora variegata (Phaeophyta) and Liagora farinosa (Rhodophyta). Caulerpa paspaloides (Chlorophyta) was active only in the thrombin time test. Other seven species presented a slightly anticoagulant activity. We considered that algal extracts have substances capable of inhibit clot formation in the last steps of the coagulation cascade. The extracts could act preventing the conversion of prothrombin to thrombin, also they could act stopping the transformation of fibrinogen to convert it to fibrin o even in the polymerization of this last molecule. This is the first report of anticoagulant activity in Anadyomene stellata, Lobophora variegata and Liagora farinosa. We can concluded that these species can be considered as potentially alternative source of anticoagulant molecules
Test of quality of shrimp postlarvae in commercial hatcheries: a case study
No full textThree characteristic of postlarvae of Litopenaeus vannamei Boone which are used as indicators of postlarvae quality, were evaluated and compared as tools for internal quality control at a commercial hatchery in Ecuador, using organisms of four successive ages from each of forty different larval cultures. The results indicated that Vibrio concentration and resistance to withstand osmotic stress at any given age were not relayed, and provided little or no information to evaluate future quality in terms of survival to the point of sale test of resitance to osmotic stress. Low size variability may be used as indicative of a probable better survival to the osmotic stress test but cannot be used quantitatively as a predictive tool
Sexual reproductive biology of Brachionus quadridentatus Hermanns (Rotifera: Monogononta)
Get PDFThis study examined important aspects of the sexual reproductive biology of the monogonont rotifer Brachionus quadridentatus Hermanns. Observations on the following was made: 1) Morphological description of the male, 2) An analysis of mating behavior, 3) An analysis of female and male life-span at 25o C, and 4) Morphometric characterization of the three types of eggs known in this species and determination of hatching percentages of sexual eggs at 20 and 25oC. SEM photographs of the male are included, the female and parthenogenetic and sexual eggs. Some complementary photographs with the light microscope are also included. The mating behavior of B. quadridentatus is similar to those of other brachionids. Attempted copulations lasted on average 12.4 s, and completed copulations lasted on average 71.4 s. B. quadridentatus is the Brachionus species with the longest duration of copulation recorded so far. Photographs showing episodes of mating attempts and copulations are included. Mating attempts and copulations are similar to those of other members of Brachionus. A comparison of the mating of B. quadridentatus with that of other brachionids is also included
Zooplancton de los sistemas estuarinos de Chantuto y Panzacola, Chiapas, en época de secas y lluvias
Get PDFZooplankton composition and abundance study from Chantuto and Panzacola estuarine systems, Chiapas, in dry (May of 1997) and rainy seasons (July of 1997) is presented. Zooplankton samples were taken using a standard net with 30 cm in mouth diameter and a mesh opening of 250 µm. Temperature, salinity, pH, and dissolved oxygen were measured in the water. The differences of the physical-chemical parameters among the dry and rainy seasons were found in the salinity averages, 23 to 13 psu respectively and in the percentages of oxygen saturation , 90 to 50 % respectively. Twenty species of zooplankton were identified, a genus of the Phylum Chaetognatha, 11 larval forms and several non identified species of fish eggs. In the dry season the copepods Canthocalanus pauper and Pseudodiaptomus culebrensis were dominant while in rainy season the dominant species was Oithona nana. None of the mentioned copepods had been considered before as dominants in Mexican estuarine systems.Se presenta un estudio sobre la composición y abundancia del zooplancton de los sistemas estuarinos de Chantuto y Panzacola, Chiapas, en época de secas (mayo de 1997) y de lluvias (julio de 1997). Las muestras de zooplancton fueron tomadas utilizando una red estándar con diámetro de la boca de 30 cm y abertura de malla de 250 µm. Se midieron temperatura, salinidad, pH y el oxígeno disuelto del agua. Las diferencias de los parámetros físico-químicos entre la época de secas y lluvias se encontraron en los promedios de salinidad (23 a 13 ups, respectivamente) y los porcentajes de saturación de oxígeno (90 a 50%, respectivamente). Se identificaron 20 especies zooplanctónicas, un género del Phylum Chaetognatha, 11 formas larvarias y varios huevos de peces de especies no identificadas. En la época de secas dominaron los copépodos Canthocalanus pauper y Pseudodiaptomus culebrensis, mientras que en la de lluvias la dominancia fue para la especie Oithona nana. Hasta el momento ninguno de los copépodos mencionados había sido considerado como dominante en un sistema estuarino mexicano
Nuevos registros de Acetabularia schenckii y Acetabularia farlowii (Chlorophyta) para la costa del Pacífico de México
Get PDFThe occurrence of Acetabularia schenckii Möbius (Polyphysaceae, Chlorophyta) is reported for the first time in the Mexican Pacific coast, out of its common distribution range along the Atlantic coast (Caribbean and Gulf of Mexico). Likewise, new distribution localities are reported for Acetabularia farlowii Solms-Laubach in the Mexican Pacific coast. Specimens were sampled from the intertidal zone to the 2 m depth in coastal lagoons from Sinaloa State, Mexico, during 2004 and 2005. A revision of specimens deposited in herbaria was carried out to determinate the geographic distribution of both species in the Mexican Pacific coast. The scarce records of Acetabularia could be related with inaccurate identifications, the small sizes of these species and to the lack of floristic studies in the study area.Se reporta la presencia de Acetabularia schenckii Möbius (Polyphysaceae, Chlorophyta) para la costa Pacífico de México, siendo éste es el primer registro fuera de su área de distribución en la costa del Atlántico (Caribe y Golfo de México). Así mismo, se reportan nuevas localidades de distribución para Acetabularia farlowii Solms-Laubach en la costa Pacífico de México. Los ejemplares fueron recolectados desde la zona intermareal hasta los 2 m de profundidad en las Lagunas costeras de Sinaloa, México, durante 2004 y 2005. Se realizó una revisión de ejemplares depositados en herbarios para obtener la distribución geográfica de ambas especies en la costa Pacífico de México. Los escasos registros de Acetabularia, puede ser debido a las identificaciones inadecuadas, a las tallas pequeñas de éstas especies y a la escasez de estudios florísticos en el área de estudio
El género Dictyopteris J. V. Lamouroux (Dictyotales, Phaeophyceae) en las costas de México
Get PDFAn extensive bibliographic revision of the genus Dictyopteris (Dictyotales, Phaeophyceae) previously recorded in the Mexicos shores was realizated. We checked herbariums specimens that are housed in different herbaria for getting the information on this genus. Also, some samples of Dictyopteris were carried out in sixty localities from Ensenada, Baja California to Bahia San Agustin, Oaxaca in the Pacific coast and from Ciudad Madero, Tamaulipas to Banco Chinchorro, Quintana Roo at Atlantic coast of Mexico from 1988 to 2003. Analysis of this information showed us that this genus contains eight species; moreover, D. delicatula J.V. Lamouroux and D. polypodioides (De Candolle) J.V. Lamouroux are distributed for both coasts at the Pacific and Atlantic shores of Mexico. Reproductive structures of Dictyopteris jamaicensis W. Taylor are described for first time and Dictyopteris jolyana Oliveira and Furtado is a new record from the Mexican Caribbean. Morphological descriptions, cytology, reproductive stage, drawings, keys for determination, specimens examinated and distinctive characteristics of each taxon are includedSe llevó a cabo una extensa revisión bibliográfica y de ejemplares de herbario de las especies asignadas al género Dictyopteris (Dictyotales, Phaeophyceae) que han sido registradas para las costas de México, así como treinta campañas de recolección de material biológico de 1988 a 2003 en 60 localidades comprendidas desde Ensenada, Baja California a Bahía de San Agustín, Oaxaca en la costa del Pacífico y de Ciudad Madero, Tamaulipas hasta Banco Chinchorro, Quintana Roo, en la costa del Atlántico de México. Los resultados obtenidos indican que el género Dictyopteris se encuentra representado por ocho especies: D. delicatula J.V. Lamouroux y D. polypodioides (De Candolle) J.V. Lamouroux, se distribuyen en ambas costas de México. Se registran por primera vez estructuras reproductoras de Dictyopteris jamaicencis W. Taylor y se cita por primera vez a Dictyopteris jolyana Oliveira y Furtado, para las costas del Caribe de México. Cada especie se acompaña con datos sobre su morfología, citología, estado reproductivo, esquemas en cámara clara, claves dicotómicas para su determinación, ejemplares representativos examinados y características distintivas para cada taxa
Composición de hidrocarburos alifáticos en sedimentos de la laguna Sontecomapan, Ver., México
Get PDFIn this study the concentrations of 15 saturated hydrocarbons (SH) were determined, both from surface sediments and sediment core samples in Sontecomapan Lagoon, Veracruz, which were analyzed by gas chromatography using capillary columns and flame ionization detection (GC-FID). Total concentrations of SH in surface sediments were in an interval of 0.21 to 12.75 µgg-1 and in cores of 1.33 to 32.01 µgg-1; even carbon chains predominant in almost all samples. In surface sediments outstand the n-alkanes C20, C23, C22, C18 and C21, whereas the higher concentrations in the cores were for C30, C32, C21, C28, C20, C25, C23; basically with a preponderance of even carbons, which demonstrates biogenic origin and anthropogenic for SH, this differs with other studies carried out in lagoons of the Gulf of Mexico, in which is exclusively reported the presence of biogenic hydrocarbonsEn este estudio se determinaron las concentraciones de 15 hidrocarburos saturados (HS), tanto en sedimentos superficiales como en núcleos sedimentarios en la Laguna Sontecomapan, Veracruz, los cuales fueron analizados por cromatografía de gases de alta resolución con detector de ionización de flama (CG-DIF). Las concentraciones de HS totales en sedimentos superficiales estuvieron en un intervalo de 0.21 a 12.75 µgg-1 y en los núcleos fue de 1.33 hasta 32.01 µgg-1; en casi todas las muestras predominaron las cadenas de carbonos pares. En los sedimentos superficiales destacaron los n-alcanos C20, C23, C22, C18 y C21, mientras que en los núcleos las mayores concentraciones fueron de C30, C32, C21, C28, C20, C25, C23; básicamente con una preponderancia de cadenas de carbonos pares, lo que demuestra un origen de los hidrocarburos saturados tanto biológico como antropogénico, lo cual difiere con otros estudios llevados a cabo en lagunas del Golfo de México, en las que exclusivamente se reporta la presencia de hidrocarburos biogénicos
Variación nictímera y estacional de la abundancia, riqueza y especies dominantes de peces, en un ambiente salobre de sustrato blando
Get PDFThe diel and seasonal changes of a fish community in Pueblo Viejo coastal lagoon, Veracruz, Mexico, were analyzed through six two-monthly 24-h cycles. A total of 17,660 individuals corresponding to 54 species were captured using a seine beach net. The dominant species were: Anchoa mitchilli, Cathorops melanopus, Membras martinica and Bairdiella chrysoura. The most important families were: Sciaenidae, Ariidae, Engraulidae, Gerreidae and Gobiidae. Five species, Prionotus tribulus, Eucinostomus gula, Centropomus mexicanus, Cynoscion nothus and Lupinoblennius nicholsi represent new records for this ecosystem. The environmental variables did not show significant differences among hours (Ps> 0.9), whereas the number and weight of captured individuals showed a regular pattern with a maximum peak at dusk, high values during the night, eventual smaller pulses at dawn and low values during the day. The abundance was significantly greater during the night in four of the six cycles analyzed (Ps< 0.05). Species richness was always greater during the night. In contrast, the number of dominant species was regularly greater during the day. The dominant species during the night was A. mitchilli, while M. martinica and A. mitchilli predominated during the day. Total fish capture, species richness and dominant species index were not significantly correlated (Ps>0.05) with tide, salinity or temperature. Therefore the diel variation of community structure seems to be mainly influenced by the light-darkness cycle (day and night), and this can be related with feeding and predation avoidance strategies. Although monthly means of the environmental variables did not show significant correlation with the community parameters (Ps>0.2), the behavior of the fish community structure seems to be mainly determined by production processes, rainfall and salinity.A través de seis ciclos bimestrales de 24-h, se evaluaron los cambios temporales en una comunidad de peces de la laguna de Pueblo Viejo, Veracruz. Utilizando un chichorro playero, se capturó un total de 17,660 individuos, registrándose 54 especies, siendo las dominantes Anchoa mitchilli, Cathorops melanopus, Membras martinica y Bairdiella chrysoura. Las familias mejor representadas fueron Sciaenidae, Ariidae, Engraulidae, Gerreidae y Gobiidae, existiendo nuevos registros para el sistema, Prionotus tribulus, Eucinostomus gula, Centropomus mexicanus, Cynoscion nothus y Lupinoblennius nicholsi. Las variables ambientales no mostraron diferencias significativas entre horas (Ps>0.9), mientras que el patrón nictímero del número y peso de individuos capturados fue consistente en todos los ciclos, presentando regularmente un máximo al anochecer, valores altos durante la noche, pulsos eventuales más pequeños al amanecer y bajas abundancias durante el día. Así, en cuatro de los seis ciclos, la abundancia fue significativamente mayor durante la noche (Ps<0.05). La riqueza de especies siempre fue mayor durante la noche, mientras que el número de especies dominantes fue regularmente mayor durante el día. La especie que predominó durante la noche fue A. mitchilli, mientras que durante el día, predominaron M. martinica y A. mitchilli. La abundancia, riqueza y número de especies dominantes no se correlacionaron (Ps>0.05) con la marea, salinidad y temperatura, por lo que la variabilidad nictímera de la estructura de la comunidad parece estar influenciada principalmente por el ciclo luz-oscuridad (día y noche), lo que a su vez se puede relacionar con estrategias de alimentación y de protección contra la depredación. Estacionalmente, aunque los promedios mensuales de las variables ambientales no se correlacionaron con los parámetros de la comunidad (Ps>0.2), los procesos de producción, precipitación y salinidad, parecen determinar en mayor grado el comportamiento de la estructura de la comunidad