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  • 1
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    Fuentes de arenas biogénicas de la playa Varadero, Matanzas, Cuba. II. Moluscos y foraminíferos (2018)
    Details
    Publication Date: 2021-05-19
    Description: Se realizó un estudio de las comunidades de moluscos y foraminíferos bentónicos como posibles productores de bioclastos, en la playa de Varadero y zonas aledañas en abril del 2001. Se inventariaron 106 especies de moluscos y 12 de foraminíferos. La riqueza de especies según el índice de Margalef (5,7 - 9,3) y la densidad (190,9-1228,6 ind.m-2) de moluscos fueron altas, mientras que la biomasa fue baja (0,6 - 66,2 g.m-2), debido al pequeño tamaño que tiene la mayoría de las especies recolectadas. La riqueza de especies de foraminíferos fue baja (0,2-0,8), pero las densidades altas (412,1 -16630,5 NFv.m2). No se observó ninguna tendencia espacial en cuanto a la distribución de ambos grupos en la zona de estudio. Se recomienda un estudio que integre las tasas de sedimentación, origen y la edad de los sedimentos para conocer si la tasa de producción actual de bioclastos en la playa Varadero es suficiente para equilibrar la pérdida de sedimento que se está produciendo.
    Description: A study about mollusk and foraminifera benthonic communities as possible bioclast producers in Varadero beach and surrounding areas was carried out in April 2001. One hundred and six species of mollusks and 12 of foraminifera were inventoried. Mollusk species richness according to Margalef index (5.7 – 9.3) and their density (190.9 – 1228.6 ind.m-2) were high, while their biomass was low (0.6 – 66.2 g.m-2), due to the small size of most collected species. Foraminifera species richness (0.2 – 0.8) was low, but their densities were high (412.1 -16630.5 NFv.m-2). No spatial tendency was found in the distribution of both groups in the study area. A study that integrates sedimentation rates, origin and age of sediments is recommended to determine if current bioclastic production rate in Varadero beach is sufficient to balance the sediment losses that are taking place.
    Description: Published
    Keywords: Moluscos ; foraminíferos ; bioclastos ; playa Varadero ; Matanzas ; Cuba
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp. 36-48
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  • 2
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    Fuentes de arenas biogénicas de la playa Varadero, Matanzas, Cuba. I. Macroalgas. (2018)
    Details
    Publication Date: 2021-05-19
    Description: La arena de la playa de Varadero está constituida mayormente por macroalgas calcáreas, moluscos y foraminíferos. El objetivo del presente trabajo fue evaluar la abundancia de las macroalgas productoras de bioclastos en los biotopos sublitorales de la zona. Se realizó la identificación específica de las algas, y se estimó su abundancia y contenido de carbonato de calcio. Se encontraron 45 taxones infragenéricos, 31 de las cuales fueron de los órdenes Corallinales, Nemaliales, Siphonocladales, Bryopsidales y Dasycladales. Predominó el género Halimeda, seguido de un césped formado por Jania spp. y Amphiroa spp. Los valores mayores de cobertura, biomasa y contenido de carbonato de calcio en las macroalgas calcáreas estaban en los fondos rocosos con una fina capa de sedimentos, desde la zona central hacia el extremo Norte; mientras que hacia el Sur del Hotel Oasis no se hallaron comunidades significativas. Al Norte de la Península Hicacos se observaron áreas con pastos marinos y una menor cobertura de macroalgas.
    Description: Sands of Varadero beach are constituted by calcareous macroalgae, mollusks and foraminifera. The objective of the present work was to assess the main characteristics of calcareous macroalgae associations in subtidal biotopes of the area. Calcareous algae were identified, and their abundance and calcium carbonate content were estimated. Forty-five infrageneric taxa of macroalgae were found, 31 of them being calcareous algae belonging to the orders Corallinales, Nemaliales, Siphonocladales, Bryopsidales, and Dasycladales. The genus Halimeda dominated, followed by a turf of Jania spp. and Amphiroa spp. Higher values of coverage, biomass and density of calcium carbonate in calcareous macroalgae were found in rocky bottoms with a thin layer of sediments, from the central zone of the peninsula up to the northern end; while no important quantity of calcareous macroalgae was found south of the Oasis Hotel. Northward of Hicacos peninsula, seagrass areas with a lower cover of macroalgae were observed.
    Description: Published
    Keywords: Macroalgas marinas ; carbonato de calcio ; playa Varadero ; Matanzas ; Cuba
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp. 22-35
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  • 3
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    Detección de los géneros de dinoflagelados potencialmente tóxicos Prorocentrum y OstreoPsis en el Banco puntalón, región surcentral de Cuba (2021)
    Details
    Publication Date: 2021-05-19
    Description: Varias especies de dinoflagelados bentónicos son productores de potentes toxinas que pueden tener impactos negativos en la economía y la salud de territorios costeros. En un estudio realizado en una zona de alto riesgo de ciguatera localizada al extremo este del golfo de Batabanó, se determinó la diversidad de especies de Gambierdiscus, organismo productor de ciguatoxinas, sin embargo no se evaluó la pre- sencia y abundancia de otros géneros de dinoflagelados bentónicos potencialmente tóxicos. En el presente estudio se re-analizaron las muestras obtenidas a partir de sustratos artificiales y naturales con el objetivo de estudiar la abundancia de otros géneros de dinoflagelados en el área. Se identificaron los géneros Prorocentrum y Ostreopsis en todos los puntos de muestreo. De forma general se encontró una alta variabilidad de la abundancia de estos géneros entre los sitios y fueron valores superiores con respecto a la abundancia reportada del género Gambierdiscus. Los resultados obtenidos mediante el uso de ambos tipos de sustratos fueron similares, lo cual justifica el uso de sustratos artificiales para la cuantificación de dinoflagelados bentónicos en futuros estudios. Este trabajo contribuye a la información existente sobre la presencia y abundancia de los dinoflagelados bentónicos potencialmente tóxicos en la región surcentral de Cuba y proporciona elementos básicos para la evaluación de riesgo relacionada con los eventos de floraciones tóxicas de estas microalgas.
    Description: Several species of benthic dinoflagellates produce potent toxins that have negative impacts on the economy and human health of coastal zones. In a previous study carried out in a zone known to be prone to ciguatera, located at the eastern end of the Gulf of Batabanó, the species diversity of ciguatoxin producer organism, Gambierdiscus, was deter- mined, however the presence and abundance of other potentially toxic benthic dinoflagellate genera was not considered. In present study, the samples obtained from artificial and natural substrates were re-analyzed to estimate the abundance of other genera of dinoflagellates in the area. The genera Proro- centrum and Ostreopsis were identified at all sampling points. In general, the abundance of these genera showed high variability between sites and were higher compared to the reported abundance of the genus Gambierdiscus. The results obtained by using both types of substrates were similar, which en- courages the use of artificial substrates for quantifying benthic dinoflagellates in future studies. This work contributes to the available information about the presence and abundance of potentially toxic benthic dinoflagellates in the southern central region of Cuba and provides basic elements for risk assessment related to toxic blooms of these microalgae.
    Description: Published
    Description: Refereed
    Keywords: Cuba ; Dinoflagelados bentónicos ; Sustratos artificiales ; Gambierdiscus ; Ostreopsis ; Prorocentrum ; Artificial substrates ; Benthic dinoflagellates
    Repository Name: AquaDocs
    Type: Journal Contribution
    Format: pp.1-10
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  • 4
    Electronic Resource
    Electronic Resource
    Middle-ear development: II. Morphometric changes in the conducting apparatus of the chick (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 212 (1992), S. 257-267 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ontogeny of various middle-ear structures was examined in 11 groups of chicks between 10 days embryonic and adult. Measurements of the tympanic membrane surface area and height, columella length, and that of the columella footplate, annular ligament, and oval window area were obtained using video micrographs and computer digitization techniques. The oval window matures first at 53 days post-hatching, whereas the columella achieves adult size at 74 days. The tympanic membrane surface area is the last middle-ear variable studied to reach adult size (79 days post-hatch). The columella increases its length from 0.63 mm (10 days embryonic) to 2.73 mm in the adult. The tympanic membrane area expands by 280% whereas the columellar footplate area increases by 11x. As a result, the pressure amplification of the middle ear due to the tympanic membrane/columellar footplate area ratio improves by over 400%. These data further contribute to our understanding of the functional development of the middle ear. © 1992 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052120305
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  • 5
    Electronic Resource
    Electronic Resource
    Structural evidence for contractile units in the giant smooth muscle cell of Beröe (1986)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 6 (1986), S. 153-158 
    Details
    ISSN: 0886-1544
    Keywords: giant smooth muscle fiber ; ctenophore ; myofilaments ; ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Bundles of giant smooth muscle fibers of the ctenophore Beröe have been stretched up to four times their initial length and then examined by transmission electron microscopy. Stretching induces the segregation of actin and thick (myosinlike) filaments into separate domains. The thick filaments domains are made of 20-30 filaments, with a regular spacing identical to that of nonstretched fibers. A moderate stretching permits the visualization of microtendons associating actin filament bundles to hyaluronidase-resistant condensations of the extracellular matrix. It is deduced from these observations that Beröe giant smooth muscle fibers possess myofibrils which attach at both ends upon the sarcolemmal membrane. Each myofibril is probably made of two long actin filament bundles (of approximately 150 filaments) and short (2-3 μm) myosinlike bundles (of approximately 30 filaments).
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970060213
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  • 6
    Electronic Resource
    Electronic Resource
    Mechanism-based isocoumarin inhibitors for serine proteases: Use of active site structure and substrate specificity in inhibitor design (1989)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 39 (1989), S. 33-46 
    Details
    ISSN: 0730-2312
    Keywords: anticoagulants ; blood coagulation enzymes ; elastase ; emphysema ; isocoumarins ; molecular modeling ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Isocoumarins are potent mechanism-based heterocyclic irreversible inhibitors for a variety of serine proteases. Most serine proteases are inhibited by the general serine protease inhibitor 3,4-dichloroisocoumarin, whereas isocoumarins containing hydrophobic 7-acylamino groups are potent inhibitors for human leukocyte elastase and those containing 7-alkylureidogroups are inhibitors for porcine pancreatic elastase. Isocoumarins containing basic side chains that resemble arginine are potent inhibitors for trypsin-like enzymes. A number of 3-alkoxy-4-chloro-7-guanidinoisocoumarins are potent inhibitors of bovine thrombin, human factor Xa, human factor XIa, human factor XIIa, human plasma kallikrein, porcine pancreatic kallikrein, and bovine trypsin. Another cathionic derivative, 4-chloro-3-(2-isothiureidoethoxy) isocoumarin, is less reactive toward many of these enzymes but is an extremely potent inhibitor of human plasma kallikrein. Several guanidinoisocoumarins have been tested as anticoagulants in human plasma and are effective at prolonging the prothrombin time. The mechanism of inhibition by this class of heterocyclic inactivators involves formation of an acyl enzyme by reaction of the active site serine with the isocoumarin carbonyl group. Isocoumarins with 7-amino or 7-guanidino groups will then decompose further to quinone imine methide intermediates, which react further with an active site residue (probably His-57) to form stable inhibited enzyme derivatives. Isocoumarins should be useful in further investigations of the physiological function of serine proteases and may have future therapeutic utility for the treatment of emphysema and coagulation disorders.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240390105
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  • 7
    Electronic Resource
    Electronic Resource
    Activation of phospholipase D by ras proteins is independent of protein kinase C (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 61 (1996), S. 599-608 
    Details
    ISSN: 0730-2312
    Keywords: ras proteins ; growth factors ; phospholipase D ; PKC ; phorbol esters ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Growth factors activate phospholipases, causing the generation of diverse lipid metabolites with second messenger function. Among them, the phosphatidylcholine-preferring phospholipase D (PLD) has attracted great interest, since in addition to the transient activation by growth factors stimulation, it is constitutively activated in some of the src- and ras-transformed cells investigated. To establish further the functional relationship of ras oncogenes with PLD, we have investigated its mechanism of regulation. Growth factors such as PDGF or FGF activate the PC-PLD enzyme by a common, PKC-dependent mechanism. By contrast, ras oncogenes activate the PC-PLD enzyme by a PKC-independent mechanism. These results suggest the existence of at least two mechanisms for PLD activation, and ras oncogenes contribute to one of them. © 1996 Wiley-Liss, Inc.
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  • 8
    Electronic Resource
    Electronic Resource
    Histochemical and ultrastructural study of the digestive tract of the tortoise Testudo graeca (Testudines) (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 204 (1990), S. 235-245 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The digestive tract of the tortoise Testudo graeca (Testudines) was investigated by means of light and electron microscopy. The esophagus of T. graeca was lined by two types of epithelium: non-keratinized stratified squamous in the upper portion and stratified columnar in the lower. The lamina propria of the esophagus contained tubular or tubuloacinar glands. The mucosa of the stomach showed similar characteristics to those of other reptiles. The small intestine exhibited longitudinal folds lined by absorptive and goblet cells. The large intestine was lined by columnar mucous cells. Within the lamina propria of the large intestine, masses of 10-15 epithelial cells connecting with the surface epithelium by means of slender cytoplasmic processes were observed. A battery of six lectins (Con-A, PNA, WGA, DBA, SBA, and LTA) was used to identify the epithelial mucins. WGA and DBA reacted with all types of mucous cells throughout the alimentary canal. PNA was only unreactive in the intestine, LTA in the esophagus, and SBA in the large intestine. These results indicate a similar lectin-binding pattern throughout the gut of T. graeca.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052040302
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  • 9
    Electronic Resource
    Electronic Resource
    F-actin in guinea pig spermatozoa: Its role in calmodulin translocation during acrosome reaction (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 33 (1992), S. 172-181 
    Details
    ISSN: 1040-452X
    Keywords: F-actin in guinea pig spermatozoa ; Calmodulin ; Cytochalasin D ; Phalloidin-rhodamine ; Acrosomal reaction ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The presence of actin has been determined in mammalian spermatozoa. However, its function in these cells is still almost unknown. Only in boar spermatozoa has evidence for F-actin and a possible function for it been presented. In this work, actin distribution and F-actin were determined in uncapacitated, capacitated, and acrosomal-reacted guinea pig spermatozoa, by means of monoclonal and polyclonal antibodies, using an indirect immunoperoxidase technique, and by the use of rhodamine-phalloidin. With the last probe we found filamentous actin in these cells. By both techniques, actin was detected in the acrosome and in the entire tail. In some cells with acrosomal reaction, actin was also detected in the equatorial and in the postacrosomal regions. SDS-PAGE and Western blots immunostained with monoclonal and polyclonal anti-actin antibodies confirmed the presence of actin in extracts of guinea pig spermatozoa. Actin was also detected in preparations of Percoll-purified spermatozoa. We have communicated that guinea pig spermatozoa show a change on calmodulin location during the acrosome reaction. They present it first in the equatorial region and later in the postacrosomal region. To determine if F-actin participates in this calmodulin translocation, we studied the effect of cytochalasin D. It was found that the number of cells with calmodulin in the equatorial region increased in the presence of cytochalasin D while the number of cells with calmodulin in the postacrosomal region decreased. We also found that after cytochalasin D treatment acrosome loss was increased and sperm motility was slightly inhibited. Our results suggest that actin participate in calmodulin translocation to the postacrosomal region during acrosome reaction, in maintaining the acrosome structure, and perhaps also in sperm motility. © 1992 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080330209
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  • 10
    Electronic Resource
    Electronic Resource
    Expression of bovine trophoblast interferons by in vitro-derived blastocysts is correlated with their morphological quality and stage of development (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 36 (1993), S. 1-6 
    Details
    ISSN: 1040-452X
    Keywords: Blastocyst ; Embryo ; Embryonic development ; In vitro fertilization ; Trophectoderm ; Trophoblast interferon ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Bovine embryos, whether produced naturally or by in vitro techniques, exhibit considerable variability in morphological quality and develop at different rates. Our objectives have been to determine whether initial expression of trophoblast interferon (IFN-τ) was a reflection of conceptus stage of development or age and whether there was an effect of embryo quality on the amount of IFN-τ produced. Early blastocysts (N =187) were selected at the onset of blastocoele formation and cultured individually. Embryo quality (excellent, good, or fair: E, G, or F) and developmental stage (early, expanded and hatched blastocysts: BL, EBL, and HBL, respectively) were used in a 3 x 3 factorial complete randomized block design, each block (n = 4) consisting of batches of embryos produced from oocytes in different collections. Quality and developmental stage of embryos and IFN-τ released into the medium were assessed every 24 h. Production of IFN-τ (units/embryo/24 h) was greater (P 〈 0.01) among hatched blastocysts (HBL; 0.91 ± 0.08) than expanded blastocysts (EBL; 0.23 ± 0.04) and early blastocysts (BL; 0.05 ± 0.08). Embryos of similar developmental stage but differing by 2 days in age released equal amounts of IFN-τ. Expression of antiviral activity increased (P 〈 0.05) from 27% to 57% to 100% as development proceeded from BL to EBL and to HBL respectively. More IFN-τ was produced by HBL graded G (1.0 ± 0.1) or E (1.3 ± 0.1) than by those of F quality (0.5 ± 0.1). All blastocysts, whatever their quality and developmental stage, contained IFN-± mRNA. Therefore, developmental stage and quality of the embryos significantly influence the expression of IFN-±. The amount produced may be a useful objective indicator of embryo quality. © 1993 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080360102
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