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Sample records for brachionus rotundiformis tschugunoff

  1. PENYIMPANAN ROTIFERA INSTAN (Brachionus rotundiformis PADA SUHU YANG BERBEDA DENGAN PEMBERIAN PAKAN MIKROALGA KONSENTRAT

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    Erlania Erlania

    2016-11-01

    Full Text Available Keberhasilan kegiatan budidaya perikanan harus ditunjang dengan ketersediaan benih yang berkesinambungan. Oleh karena itu, diperlukan juga ketersediaan pakan alami larva berupa rotifera (Brachionus rotundiformis. Desain percobaan berupa rancangan faktorial dengan dua faktor dan lima ulangan diaplikasikan dalam penelitian ini. Sebagai perlakuan berupa suhu ruang penyimpanan (suhu kamar, suhu ruang AC, dan suhu refrigerator/lemari es dan pakan mikroalga konsentrat (monospesies dan multispesies. Bakteri probiotik juga digunakan sebagai pengontrol kualitas air. Spesies mikroalga yang digunakan adalah Nannochloropsis sp., Dunaliella sp., Isochrysis sp., dan Pavlova sp. Parameter yang diukur adalah kelimpahan rotifera dan parameter kualitas air media kultur (pH, salinitas, DO, dan NH3. Analisis data terdiri atas analisis regresi, analisis ragam, dan uji keparalelan. Hasil pengukuran parameter kualitas air selama penyimpanan menunjukkan kondisi media yang relatif stabil dan merupakan kisaran optimum bagi pertumbuhan B. rotundiformis. Kelimpahan maksimum tertinggi dari B. rotundiformis baik pada perlakuan pakan monospesies maupun multispesies alga adalah pada suhu kamar. Dari interaksi kedua perlakuan, diperoleh kelimpahan akhir tertinggi pada suhu ruang AC–pakan multispesies. Hal ini menunjukkan bahwa rotifera dapat disimpan lebih lama pada suhu ruang AC dengan pemberian pakan multispesies alga. The success of any aquaculture practices should be supported by sustainable supply of fish fry. Therefore, the availability of rotifers (Brachionus rotundiformis as natural feed for fish larvae is required. The research was arranged in factorial design with two treatments and five replications. Treatments consisted of different room storage temperatures (refrigerator, room temperature, and room with air conditioner/AC and microalgae concentrate added as rotifer feed (monospecies and multispecies algae. Probiotic bacteria was used to control water quality

  2. PENAMBAHAN TAURIN MELALUI ROTIFER Brachionus rotundiformis UNTUK PERBAIKAN PERTUMBUHAN LARVA DAN PENINGKATAN PRODUKSI BENIH KERAPU SUNU, Plectropomus leopardus

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    Regina Melianawati; Ni Wayan Widya Astuti

    2012-01-01

    Ikan kerapu sunu Plectropomus leopardus merupakan komoditas perikanan laut yang bernilai ekonomis tinggi, sehingga perlu dikembangkan dalam skala budidaya. Untuk meningkatkan keberhasilan pembenihan maka kualitas rotifer Brachionus rotundiformis sebagai pakan alami bagi larva perlu ditingkatkan. Uji coba penggunaan taurin sebagai salah satu bahan pengkaya rotifer perlu dilakukan, mengingat taurin merupakan asam amino bebas yang diharapkan dapat diabsorbsi dengan mudah dan cepat oleh larva. Pe...

  3. PENAMBAHAN TAURIN MELALUI ROTIFER Brachionus rotundiformis UNTUK PERBAIKAN PERTUMBUHAN LARVA DAN PENINGKATAN PRODUKSI BENIH KERAPU SUNU, Plectropomus leopardus

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    Regina Melianawati

    2012-12-01

    nyata pada kedua perlakuan (P<0,05. Sintasan benih kerapu sunu pada perlakuan A lebih tinggi (1,45% dibandingkan pada perlakuan B (0,01% (P<0,01. Dengan demikian maka penambahan taurin dapat meningkatkan pertumbuhan dan sintasan larva kerapu sunu.

  4. Lagenidium callinectes INFECTION ON ROTIFERS Brachionus sp.

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    Des Roza

    2007-06-01

    Full Text Available Milkfish, Chanos chanos and humpback grouper, Cromileptes altivelis hatcheries have developed at Gondol, Bali since 1995 and until now still rely on rotifers, the main natural food, supply. Recent problem on mass culture of rotifer, Brachionus sp. is harvest failure caused by fungus infection. Under light microscope, infected eggs and bodies of the rotifers was filled with numerous aseptate hyphae. Two isolates of fungi were isolated from rotifer eggs and carcass on June 21st, 2004 and on June 25th, 2004 obtained from milkfish and humpback grouper hatcheries at Gondol. Based on its morphological characteristics, the pathogenic fungus was identified as Lagenidium callinectes which grows optimally at 25°C and survives in 1.0%, 2.5%, and 5.0% NaCl as well as in 1.0% and 2.5% KCl. Both of the present isolates utilize only 8 out of 26 carbohydrates and derivatives tested as carbon, nutrition and energy sources. This finding is the first report on rotifer, Brachionus sp. infected with L. callinectes causing up to 100% mortality.

  5. Culture of the freshwater rotifer, Brachionus calyciflorus , and its ...

    African Journals Online (AJOL)

    This paper attempts to review the principles and procedures involved in the culture of the freshwater rotifer, Brachionus calyciflorus as starter food for most freshwater fish fry. There are several strains of different sizes of this rotifer, thus making them suitable for fry of a variety of sizes. This rotifer can be isolated, continuously ...

  6. Ecological differentiation in cryptic rotifer species: what we can learn from the Brachionus plicatilis complex.

    Czech Academy of Sciences Publication Activity Database

    Gabaldón, Carmen; Fontaneto, D.; Carmona, M.J.; Montero-Pau, J.; Serra, M.

    2017-01-01

    Roč. 796, č. 1 (2017), s. 7-18 ISSN 0018-8158 Institutional support: RVO:60077344 Keywords : Brachionus plicatilis * coexistence * ecological differentiation * molecular taxonomy Subject RIV: DA - Hydrology ; Limnology Impact factor: 2.056, year: 2016

  7. Two Circular Chromosomes of Unequal Copy Number Make Up the Mitochondrial Genome of the Rotifer Brachionus plicatilis

    National Research Council Canada - National Science Library

    Suga, Koushirou; Mark Welch, David B; Tanaka, Yukari; Sakakura, Yoshitaka; Hagiwara, Atsushi

    2008-01-01

    The monogonont rotifer Brachionus plicatilis is an emerging model system for a diverse array of questions in limnological ecosystem dynamics, the evolution of sexual recombination, cryptic speciation...

  8. Ingestion of Brachionus plicatilis under different microalgae conditions

    Science.gov (United States)

    Zhou, Wenli; Tang, Xuexi; Qiao, Xiuting; Wang, You; Wang, Renjun; Feng, Lei

    2009-09-01

    The effects of four microalgae, Chlorella vulgaris, Platymonas helgolandicavar, Isochrysis galbana, and Nitzschia closterium on the grazing and filtering rates of the marine rotifer, Brachionus plicatilis, were evaluated under laboratory conditions. The grazing rates in separate cultures of the four microalga were as follows: C. vulgaris > P. helgolandicavar > I. galbana > N. closterium. However, the filtering rates occurred in the following order: P. helgolandicavar > N. closterium > C. vulgaris > I. galbana. A mixed diets experiment revealed that P. helgolandicavar was the preferred diet of B. plicatilis. In addition, the grazing rate of B. plicatilis increased gradually as the density of the microalgae increased, until concentrations of 2.5×106 cells mL-1 for C. vulgaris and 1.5×106 cells mL-1 for I. galbana were obtained. Furthermore, the filtering rate increased slightly when the density of the microalgae was low, after which it declined as the microalgal density increased. The grazing rates of B. plicatilis were as follows during the different growth phases: stationary phase > exponential phase > lag phase > decline phase. Additionally, the filtering rates during the growth phases were: exponential phase > lag phase > stationary phase > decline phase. The results of this study provide foundational information that can be used to explore the optimal culture conditions for rotifers and to promote the development of aquaculture.

  9. Infochemical-mediated trophic interactions between the rotifer Brachionus calyciflorus and its food algae

    NARCIS (Netherlands)

    Verschoor, A.M.; Zadereev, Y.S.; Mooij, W.M.

    2007-01-01

    We studied how chemicals obtained as filtrates from algal monocultures (algal chemicals) and from rotifer cultures with or without algae (rotifer chemicals) affected feeding rates of the rotifer Brachionus calyciflorus on its food algae, both directly and indirectly (through chemical-induced changes

  10. Genetic determinants of mate recognition in Brachionus manjavacas (Rotifera).

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    Snell, Terry W; Shearer, Tonya L; Smith, Hilary A; Kubanek, Julia; Gribble, Kristin E; Welch, David B Mark

    2009-09-09

    repeats are kept nearly identical through a process of concerted evolution. Information-rich molecules like surface glycoproteins are well adapted for chemical communication and aquatic animals may have evolved signaling systems based on these compounds, whereas insects use cuticular hydrocarbons. Owing to its critical role in mating, the mate recognition pheromone gene will be a useful molecular marker for exploring the mechanisms and rates of selection and the evolution of reproductive isolation and speciation using rotifers as a model system. The phylogenetic variation in the mate recognition pheromone gene can now be studied in conjunction with the large amount of ecological and population genetic data being gathered for the Brachionus plicatilis species complex to understand better the evolutionary drivers of cryptic speciation.

  11. Genetic determinants of mate recognition in Brachionus manjavacas (Rotifera

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    Kubanek Julia

    2009-09-01

    , even at synonymous positions, suggests that the repeats are kept nearly identical through a process of concerted evolution. Information-rich molecules like surface glycoproteins are well adapted for chemical communication and aquatic animals may have evolved signaling systems based on these compounds, whereas insects use cuticular hydrocarbons. Conclusion Owing to its critical role in mating, the mate recognition pheromone gene will be a useful molecular marker for exploring the mechanisms and rates of selection and the evolution of reproductive isolation and speciation using rotifers as a model system. The phylogenetic variation in the mate recognition pheromone gene can now be studied in conjunction with the large amount of ecological and population genetic data being gathered for the Brachionus plicatilis species complex to understand better the evolutionary drivers of cryptic speciation.

  12. Population density, sexual reproduction and diapause in monogonont rotifers: new data for Brachionus and a review

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    John J. GILBERT

    2004-09-01

    Full Text Available Diapausing, fertilized eggs in monogonont rotifers typically are formed after an environmental signal induces amictic females to produce mictic daughters. Mictic females lay haploid eggs that may develop parthenogenetically into males, or that may be fertilized and develop into diapausing, female embryos called resting eggs. Laboratory experiments demonstrate that crowding is the signal for production of mictic females in strains of Brachionus calyciflorus from Texas, Spain and Germany, and in a strain of Brachionus variabilis from Spain. In these experiments, newborn amictic females were cultured singly in large and small volumes to give lowand high-density treatments. Therefore, the induction of mictic females is due exclusively to population density and cannot be attributed to a grouping effect involving some interaction among individuals. B. variabilis is very sensitive to population density; females had to be cultured in 30 ml to prevent appreciable production of mictic daughters. Crowding is now known to be the signal for initiation of sexuality and diapause in four species of Brachionus, two species of Epiphanes, and Rhinoglena frontalis. The chemical that mediates this response somehow influences oocytes in the maternal body cavity to differentiate into mictic females. Aggregation of individuals in natural systems may facilitate the production of mictic females. In some of these rotifers, the response to crowding is suppressed in early generations from the resting egg, assuring that clonal populations will attain higher population densities before committing to sexual reproduction. Fitness benefits of the mictic-female response to crowding, and to other environmental signals in other rotifers (dietary tocopherol, long photoperiod, are discussed.

  13. Germ cell specification and ovary structure in the rotifer Brachionus plicatilis

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    Smith James M

    2010-08-01

    Full Text Available Abstract Background The segregation of the germline from somatic tissues is an essential process in the development of all animals. Specification of the primordial germ cells (PGCs takes place via different strategies across animal phyla; either specified early in embryogenesis by the inheritance of maternal determinants in the cytoplasm of the oocyte ('preformation' or selected later in embryonic development from undifferentiated precursors by a localized inductive signal ('epigenesis'. Here we investigate the specification and development of the germ cells in the rotifer Brachionus plicatilis, a member of the poorly-characterized superphyla Lophotrochozoa, by isolating the Brachionus homologues of the conserved germ cell markers vasa and nanos, and examining their expression using in situ hybridization. Results Bpvasa and Bpnos RNA expression have very similar distributions in the Brachionus ovary, showing ubiquitous expression in the vitellarium, with higher levels in the putative germ cell cluster. Bpvas RNA expression is present in freshly laid eggs, remaining ubiquitous in embryos until at least the 96 cell stage after which expression narrows to a small cluster of cells at the putative posterior of the embryo, consistent with the developing ovary. Bpnos RNA expression is also present in just-laid eggs but expression is much reduced by the four-cell stage and absent by the 16-cell stage. Shortly before hatching of the juvenile rotifer from the egg, Bpnos RNA expression is re-activated, located in a subset of posterior cells similar to those expressing Bpvas at the same stage. Conclusions The observed expression of vasa and nanos in the developing B. plicatilis embryo implies an epigenetic origin of primordial germ cells in Rotifer.

  14. Effect of aldrin on life history characteristics of rotifer Brachionus calyciflorus pallas.

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    Huang, L; Xi, Y-L; Zha, C-W; Zhao, L-L

    2007-11-01

    The organochlorine insecticide aldrin is commonly used in intensive agriculture, and demonstrates estrogenic activity. Rotifers such as Brachionus calyciflorus are favored test animals in aquatic toxicology because of their more sensitivity to most toxicants. In the tested concentration range of 0.04-1.28 mg/L, aldrin shortened significantly the durations of embryonic development. Lower concentrations of aldrin had an intriguing effect on the reproduction of the rotifers and are beneficial to their survival. Different endpoints of both development and reproduction had different sensitivity to aldrin. The reproductive endpoint of the rotifers is more sensitive to aldrin than the developmental endpoint.

  15. Cholinergic neuromuscular junctions in Brachionus calyciflorus and Lecane quadridentata (Rotifera: Monogononta

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    Ignacio Alejandro Pérez-Legaspi

    2014-05-01

    Full Text Available Objective: To identify the presence of joint muscular and cholinergic systems in two freshwater rotifer species, Brachionus calyciflorus and Lecane quadridentata. Methods: The muscle actin fibers were stained with phalloidin-linked fluorescent dye, and acetylcholine was detected with Amplex Red Acetylcholine/Acetylcholinesterase Assay Kit, and then confocal scanning laser microscopy was used. Results: The musculature of Brachionus calyciflorus showed a pattern similar to other species of the same genus, while that of Lecane quadridentata was different from other rotifer genera described previously. The cholinergic system was determined by co-localization of both muscles and acetylcholine labels in the whole rotifer, suggesting the presence of neuromuscular junctions. Conclusions: The distribution pattern of muscular and acetylcholine systems showed considerable differences between the two species that might be related to different adaptations to particular ecological niches. The confirmation of a cholinergic system in rotifers contributes to the development of potential neuro-pharmacological and toxicological studies using rotifers as model organism.

  16. Effect of different densities of live and dead Chlorella vulgaris on the population growth of rotifers Brachionus calyciflorus and Brachionus patulus (Rotifera

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    E. Lucía-Pavón

    2001-12-01

    Full Text Available In order to maintain rotifer populations during periods of low algal production, it is necessary to offer alternate diets, some of which include forms of preserved algae. The present work is based on the effect of live and dead Chlorella vulgaris on the population growth of Brachionus calyciflorus and Brachionus patulus. The experimental design consisted of 3 algal levels (0.5x10(6, 1.5x10(6 and 4.5x10(6 cells ml-1 offered in 3 forms (living, frozen and heat-killed. The maximal population density values for B. calyciflorus ranged from 55±1 ind. ml-1 (at 0.5x10(6 cells ml-1 to 471±72 ind. ml-1 (at 4.5x10(6 cells ml-1 with live Chlorella, but was much lower (6±1 to 26±6 ind. ml-1 with frozen or heat-killed alga under comparable food levels. However, the maximum population density of B. patulus under live or or heat-killed Chlorella was similar at comparable algal levels but when offered frozen algae it was four times less. The highest mean peak population density was 1227±83 ind. ml-1 under 4.5x10(6 cells ml-1. The rate of population increase for B. calyciflorus varied from 0.50 to 0.79 using live Chlorella, but under comparable conditions, this range was lower (0.21 to 0.31 for B. patulus. Results have been discussed in light of possible application for aquaculturePara mantener poblaciones de rotíferos durante periodos con escasez de microalgas, es necesario ofrecer dietas alternativas, incluyendo algunas formas de microalgas preservadas. El presente trabajo analiza el efecto de Chlorella vulgaris viva y muerta sobre el crecimiento poblacional de Brachionus calyciflorus y Brachonus patulus. El diseño experimental consistió en tres niveles de algas (0.5x10(6, 1.5x10(6 y 4.5x10(6 células ml-1 ofrecidas en tres formas (viva, congelada y muerta con agua caliente. Las abundancias máximas de población de B. calyciflorus variaron desde 55±1 ind. ml-1 (en 0.5x10(6 células ml-1 a 471±72 ind. ml-1 (en 4.5x10(6 células ml-1 con Chlorella viva

  17. Bioconcentration and localization of lead in the freshwater rotifer Brachionus calyciflorus Pallas 1677 (Rotifera: Monogononta)

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado-Flores, Jesus, E-mail: jalvaflo@hotmail.com [Universidad Autonoma de Aguascalientes, Centro de Ciencias Basicas, Departamento de Quimica, Avenida Universidad 940, Aguascalientes, Ags., CP 20131 (Mexico); Rico-Martinez, Roberto, E-mail: rrico@correo.uaa.mx [Universidad Autonoma de Aguascalientes, Centro de Ciencias Basicas, Departamento de Quimica, Avenida Universidad 940, Aguascalientes, Ags., CP 20131 (Mexico); Ventura-Juarez, Javier, E-mail: jventur@correo.uaa.mx [Universidad Autonoma de Aguascalientes, Centro de Ciencias Basicas, Departamento de Morfologia, Avenida Universidad 940, Aguascalientes, Ags., CP 20131 (Mexico); Silva-Briano, Marcelo, E-mail: msilva@correo.uaa.mx [Universidad Autonoma de Aguascalientes, Centro de Ciencias Basicas, Departamento de Biologia, Avenida Universidad 940, Aguascalientes, Ags., CP 20131 (Mexico); Rubio-Franchini, Isidoro, E-mail: rubio_reyes@hotmail.com [Instituto de Servicios de Salud del Estado de Aguascalientes, Laboratorio Estatal de Salud Publica, Av. Siglo XXI 105, Ciudad Satelite Morelos, C.P. 20270, Aguascalientes, Ags. (Mexico)

    2012-03-15

    We studied how lead is bioconcentrated and distributed in the rotifer Brachionus calyciflorus using metal histochemistry to locate lead granules, Leadmium Green{sup Registered-Sign} analysis to establish the route of uptake, atomic absorption to determined the bioconcentration factor (BCF), and detected the presence of microelements in the cuticle by X-ray microanalysis with scanning electron microscopy. Our results indicate: (a) the digestive system is the main route of lead uptake in the rotifer B. calyciflorus, (b) after 24-h lead is deposited in granules in the mastax and vitellarium, (c) our energy-dispersive X-ray microanalysis indicates decalcification taking place in the cuticle of the rotifer after a 24-h lead exposure, and (d) we determined a BCF = 115 for lead after a 24 h exposure. However, the route of mobilization and storage of intracellular lead are still not fully understood in B. calyciflorus.

  18. [Effects of glyphosate on life histroy characteristics of freshwater rotifer Brachionus calyciflorus].

    Science.gov (United States)

    Chu, Zhaoxia; Yi, Yilong; Xu, Xiaoping; Ge, Yali; Dong, Lili; Chen, Fang

    2005-06-01

    The life table study on the life history characteristics of freshwater rotifer Brachionus calyciflorus under effects of different concentrations glyphosate showed that glyphosate had significant effects on the embryonic developmental time, duration of juvenile and reproductive periods, average lifespan, net reproductive rate, and intrinsic population increasing rate of the rotifer. The embryonic developmental time was significantly lengthened when exposed to 3 and 8 mg x L(-1) glyphosate, the juvenile period began to be lengthened significantly when exposed to 3 mg x L(-1) glyphosate, while the net reproductive rate and intrinsic population increasing rate decreased significantly when the rotifer was exposed to 8.00 and 10.50 mg x L(-1) glyphosate, respectively. Among all the parameters, intrinsic population increasing rate was the most sensitive parameter which could be used in monitoring the effects of glyphosate on the life history characteristics of B. calyciflorus.

  19. Methods for culturing saltwater rotifers (Brachionus plicatilis) for rearing larval zebrafish.

    Science.gov (United States)

    Lawrence, Christian; Sanders, Erik; Henry, Eric

    2012-09-01

    The saltwater rotifer, Brachionus plicatilis, is widely used in the aquaculture industry as a prey item for first-feeding fishes due to its ease of culture, small size, rapid reproductive rate, and amenability to enrichment with nutrients. Despite the distinct advantages of this approach, rotifers have only been sporadically utilized for rearing larval zebrafish, primarily because of the common misconception that maintaining cultures of rotifers is difficult and excessively time-consuming. Here we present simple methods for maintaining continuous cultures of rotifers capable of supporting even the very largest zebrafish aquaculture facility, with minimal investments in materials, time, labor, and space. Examples of the methods' application in one large, existing facility is provided, and troubleshooting of common problems is discussed.

  20. A Novel Method for Rearing Zebrafish by Using Freshwater Rotifers (Brachionus calyciflorus).

    Science.gov (United States)

    Aoyama, Yuta; Moriya, Natsumi; Tanaka, Shingo; Taniguchi, Tomoko; Hosokawa, Hiroshi; Maegawa, Shingo

    2015-08-01

    The zebrafish (Danio rerio) has become a powerful model organism for studying developmental processes and genetic diseases. However, there remain several problems in previous rearing methods. In this study, we demonstrate a novel method for rearing zebrafish larvae by using a new first food, freshwater rotifers (Brachionus calyciflorus). Feeding experiments indicated that freshwater rotifers are suitable as the first food for newly hatched larval fish. In addition, we revisited and improved a feeding schedule from 5 to 40 days postfertilization. Our feeding method using freshwater rotifers accelerated larval growth. At 49 dpf, one pair out of 10 pairs successfully produced six fertilized eggs. At 56, 63, and 71 dpf, 6 out of the 10 pairs constantly produced normal embryos. Our method will improve the husbandry of the zebrafish.

  1. Measurement of Survival Time in Brachionus Rotifers: Synchronization of Maternal Conditions.

    Science.gov (United States)

    Kaneko, Gen; Yoshinaga, Tatsuki; Gribble, Kristin E; Welch, David M; Ushio, Hideki

    2016-07-22

    Rotifers are microscopic cosmopolitan zooplankton used as models in ecotoxicological and aging studies due to their several advantages such as short lifespan, ease of culture, and parthenogenesis that enables clonal culture. However, caution is required when measuring their survival time as it is affected by maternal age and maternal feeding conditions. Here we provide a protocol for powerful and reproducible measurement of the survival time in Brachionus rotifers following a careful synchronization of culture conditions over several generations. Empirically, poor synchronization results in early mortality and a gradual decrease in survival rate, thus resulting in weak statistical power. Indeed, under such conditions, calorie restriction (CR) failed to significantly extend the lifespan of B. plicatilis although CR-induced longevity has been demonstrated with well-synchronized rotifer samples in past and present studies. This protocol is probably useful for other invertebrate models, including the fruitfly Drosophila melanogaster and the nematode Caenorhabditis elegans, because maternal age effects have also been reported in these species.

  2. Pastas de Rhodomonas salina (Cryptophyta como alimento para Brachionus plicatilis (Rotifera

    Directory of Open Access Journals (Sweden)

    Miguel Guevara

    2011-12-01

    Full Text Available Pastas de Rhodomonas salina, obtenidas mediante centrifugación y floculación con quitosano y preservadas con o sin vitamina C, a -20°C fueron evaluadas bioquímicamente y proporcionadas como alimento al rotífero Brachionus plicatilis. Las pastas microalgales: (1 centrifugada y con vitamina C (CV, (2 centrifugada y sin vitamina C (C, (3 floculada y con vitamina C (FV y (4 floculada y sin adición de vitamina C (F; mantuvieron sus contenidos de proteínas y lípidos totales similares al cultivo control, con valores de 40.0±2.32% y 12.0±1.45%, respectivamente. La relación feofitina a/clorofila a fue similar (0.09-0.11 entre las pastas centrifugadas y el cultivo control, pero mayor en las pastas floculadas (1.28-1.48. Las pastas centrifugadas presentaron porcentajes de PUFAs totales, EPA y DHA similares al cultivo control (PUFAs: 47%, EPA: 4% y DHA: 4.7% y superiores al de las pastas floculadas. Las pastas obtenidas por centrifugación indujeron un crecimiento del rotífero igual al obtenido con el alimento control (densidad máxima: 320rotíferos/mL; tasa instantánea de crecimiento: 0.23rotíferos/día, fecundidad: 1.49huevos/ hembra y productividad: 43x103rotíferos/L/día. Se concluye que la pasta de R. salina centrifugada y congelada a -20°C, durante cuatro semanas, sin adición de vitamina C, mantiene su calidad nutricional similar a la del alga fresca y puede ser usada como alimento de Brachionus plicatilis.

  3. Pastas de Rhodomonas salina (Cryptophyta como alimento para Brachionus plicatilis (Rotifera

    Directory of Open Access Journals (Sweden)

    Miguel Guevara

    2011-12-01

    Full Text Available Pastas de Rhodomonas salina, obtenidas mediante centrifugación y floculación con quitosano y preservadas con o sin vitamina C, a -20°C fueron evaluadas bioquímicamente y proporcionadas como alimento al rotífero Brachionus plicatilis. Las pastas microalgales: (1 centrifugada y con vitamina C (CV, (2 centrifugada y sin vitamina C (C, (3 floculada y con vitamina C (FV y (4 floculada y sin adición de vitamina C (F; mantuvieron sus contenidos de proteínas y lípidos totales similares al cultivo control, con valores de 40.0±2.32% y 12.0±1.45%, respectivamente. La relación feofitina a/clorofila a fue similar (0.09-0.11 entre las pastas centrifugadas y el cultivo control, pero mayor en las pastas floculadas (1.28-1.48. Las pastas centrifugadas presentaron porcentajes de PUFAs totales, EPA y DHA similares al cultivo control (PUFAs: 47%, EPA: 4% y DHA: 4.7% y superiores al de las pastas floculadas. Las pastas obtenidas por centrifugación indujeron un crecimiento del rotífero igual al obtenido con el alimento control (densidad máxima: 320rotíferos/mL; tasa instantánea de crecimiento: 0.23rotíferos/día, fecundidad: 1.49huevos/ hembra y productividad: 43x103rotíferos/L/día. Se concluye que la pasta de R. salina centrifugada y congelada a -20°C, durante cuatro semanas, sin adición de vitamina C, mantiene su calidad nutricional similar a la del alga fresca y puede ser usada como alimento de Brachionus plicatilis.Rhodomonas salina (Cryptophyta pastes as feed for Brachionus plicatilis (Rotifera. Rotifers are an important live feed for first feeding larvae of many fish species. The use of concentrated algae cells in the mass culture of the rotifer Brachionus plicatilis (Brachionidae has opened new horizons for research on this organism. Pastes of Rhodomonas salina (Pyrenomonadaceae obtained either by centrifugation or flocculation with chitosan were preserved, with or without vitamin C, at -20°C for four weeks and were evaluated

  4. Genome size evolution at the speciation level: The cryptic species complex Brachionus plicatilis (Rotifera)

    OpenAIRE

    Riss Simone; Stelzer Claus-Peter; Stadler Peter

    2011-01-01

    Abstract Background Studies on genome size variation in animals are rarely done at lower taxonomic levels, e.g., slightly above/below the species level. Yet, such variation might provide important clues on the tempo and mode of genome size evolution. In this study we used the flow-cytometry method to study the evolution of genome size in the rotifer Brachionus plicatilis, a cryptic species complex consisting of at least 14 closely related species. Results We found an unexpectedly high variati...

  5. Whole-mount in situ hybridization in the Rotifer Brachionus plicatilis representing a basal branch of lophotrochozoans

    OpenAIRE

    Boell, Louis; Bucher, Gregor

    2008-01-01

    In order to broaden the comparative scope of evolutionary developmental biology and to refine our picture of animal macroevolution, it is necessary to establish new model organisms, especially from previously underrepresented groups, like the Lophotrochozoa. We have established the culture and protocols for molecular developmental biology in the rotifer species Brachionus plicatilis M?ller (Rotifera, Monogononta). Rotifers are nonsegmented animals with enigmatic basal position within the loph...

  6. Speciation in ancient cryptic species complexes: evidence from the molecular phylogeny of Brachionus plicatilis (Rotifera).

    Science.gov (United States)

    Gómez, Africa; Serra, Manuel; Carvalho, Gary R; Lunt, David H

    2002-07-01

    Continental lake-dwelling zooplanktonic organisms have long been considered cosmopolitan species with little geographic variation in spite of the isolation of their habitats. Evidence of morphological cohesiveness and high dispersal capabilities support this interpretation. However, this view has been challenged recently as many such species have been shown either to comprise cryptic species complexes or to exhibit marked population genetic differentiation and strong phylogeographic structuring at a regional scale. Here we investigate the molecular phylogeny of the cosmopolitan passively dispersing rotifer Brachionus plicatilis (Rotifera: Monogononta) species complex using nucleotide sequence variation from both nuclear (ribosomal internal transcribed spacer 1, ITS1) and mitochondrial (cytochrome c oxidase subunit I, COI) genes. Analysis of rotifer resting eggs from 27 salt lakes in the Iberian Peninsula plus lakes from four continents revealed nine genetically divergent lineages. The high level of sequence divergence, absence of hybridization, and extensive sympatry observed support the specific status of these lineages. Sequence divergence estimates indicate that the B. plicatilis complex began diversifying many millions of years ago, yet has showed relatively high levels of morphological stasis. We discuss these results in relation to the ecology and genetics of aquatic invertebrates possessing dispersive resting propagules and address the apparent contradiction between zooplanktonic population structure and their morphological stasis.

  7. Reduced expression of exocytotic proteins caused by anti-cholinesterase pesticides in Brachionus calyciflorus (Rotifera: Monogononta).

    Science.gov (United States)

    Pérez-Legaspi, I A; Rico-Martínez, R; Quintanar, J L

    2015-08-01

    The organophosphate and carbamate pesticides methyl-parathion and carbaryl have a common action mechanism: they inhibit acetylcholinesterase enzyme by blocking the transmission of nerve impulses. However, they can alter the expression of exocytotic membrane proteins (SNARE), by modifying release of neurotransmitters and other substances. This study evaluated the adverse effects of the pesticides methyl-parathion and carbaryl on expression of SNARE proteins: Syntaxin-1, Syntaxin-4 and SNAP-23 in freshwater rotifer Brachionus calyciflorus. Protein expression of these three proteins was analyzed before and after exposure to these two pesticides by Western Blot. The expression of Syntaxin-1, Syntaxin-4 and SNAP-23 proteins in B. calyciflorussignificantly decreases with increasing concentration of either pesticides. This suggests that organophosphates and carbamates have adverse effects on expression of membrane proteins of exocytosis by altering the recognition, docking and fusion of presynaptic and vesicular membranes involved in exocytosis of neurotransmitters. Our results demonstrate that the neurotoxic effect of anticholinesterase pesticides influences the interaction of syntaxins and SNAP-25 and the proper assembly of the SNARE complex.

  8. Reduced expression of exocytotic proteins caused by anti-cholinesterase pesticides in Brachionus calyciflorus (Rotifera: Monogononta

    Directory of Open Access Journals (Sweden)

    IA Pérez-Legaspi

    Full Text Available AbstractThe organophosphate and carbamate pesticides methyl-parathion and carbaryl have a common action mechanism: they inhibit acetylcholinesterase enzyme by blocking the transmission of nerve impulses. However, they can alter the expression of exocytotic membrane proteins (SNARE, by modifying release of neurotransmitters and other substances. This study evaluated the adverse effects of the pesticides methyl-parathion and carbaryl on expression of SNARE proteins: Syntaxin-1, Syntaxin-4 and SNAP-23 in freshwater rotifer Brachionus calyciflorus. Protein expression of these three proteins was analyzed before and after exposure to these two pesticides by Western Blot. The expression of Syntaxin-1, Syntaxin-4 and SNAP-23 proteins in B. calyciflorussignificantly decreases with increasing concentration of either pesticides. This suggests that organophosphates and carbamates have adverse effects on expression of membrane proteins of exocytosis by altering the recognition, docking and fusion of presynaptic and vesicular membranes involved in exocytosis of neurotransmitters. Our results demonstrate that the neurotoxic effect of anticholinesterase pesticides influences the interaction of syntaxins and SNAP-25 and the proper assembly of the SNARE complex.

  9. Spermatozoon of the freshwater rotifer Brachionus calyciflorus (Rotifera, Monogononta): Advances in morphological and ultrastructural studies.

    Science.gov (United States)

    Gu, Shuyu; Li, Lian; Liang, Luxiaoxue; Liu, Xuezhou; Ouyang, Kai; Li, Jing; Yang, Jiaxin

    2015-09-01

    The morphological and ultrastructural features of the spermatozoon in Brachionus calyciflorus are described using light, fluorescence and transmission electron microscopy (TEM). The mature spermatozoon, which appears to be thread-like, is composed of a slightly expanded anterior of cell body region and a flagellum region without acrosome. The cell body region and flagellum region are respectively 16-27μm and 20-33μm in length (n=60). The spermatozoon is characterized by a mass of dense tubular materials, which occupy most of the cell. Some mitochondria are distributed around the nuclear region in the anterior of the cell body region, while in the posterior portion of cell body, the chromatin often contains a single lobated nucleus arranged at the center of cell. The flagellum contains the classic axoneme (9×2+2) and possesses lateral undulating membrane. Mature B. calyciflorus males have no germ cell stages earlier than the spermatids in the testis. TEM examination reveals rigid rods as well as predominant typical spermatozoon in the testis. Observations, based on successive photographs and videos, enabled a first-time recording of the unique inverted movement of the spermatozoon, which indicated that the movement of the spermatozoon is driven by the flagellum. Our study also provides further supplementary insights into the phylogenetic systematics of the Rotifera. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Differentiation between activity of digestive enzymes of Brachionus calyciflorus and extracellular enzymes of its epizooic bacteria

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    Wilko H. AHLRICHS

    2009-08-01

    Full Text Available The rotifer Brachionus calyciflorus was examined by scanning electron microscopy (SEM for surface-attached, i.e. epizootic, bacteria to ascertain their specific localization and thus find out if we could discern between rotifer and bacterial enzyme activity. The lorica of B. calyciflorus was colonized by one distinct type of bacteria, which originated from the algal culture used for rotifer feeding. The corona, posterior epidermis and foot of all inspected individuals were always without attached bacteria. The density of the attached bacteria was higher with the increasing age of B. calyciflorus: while young individuals were colonized by ~ tens of bacterial cells, older ones had on average hundreds to thousands of attached bacteria. We hypothesize that epizooic bacteria may produce the ectoenzymes phosphatases and β-N-acetylhexosaminidases on the lorica, but not on the corona of B. calyciflorus. Since enzyme activities of epizooic bacteria may influence the values and interpretation of bulk rotifer enzyme activities, we should take the bacterial contribution into account.

  11. Toxic effects of combined effects of anthracene and UV radiation on Brachionus plicatilis

    Science.gov (United States)

    Gao, Ceng; Zhang, Xinxin; Xu, Ningning; Tang, Xuexi

    2017-05-01

    Anthracene is a typical polycyclic aromatic hydrocarbon, with photo activity, can absorb ultraviolet light a series of chemical reactions, aquatic organisms in the ecosystem has a potential light induced toxicity. In this paper, the effects of anthracene and UV radiation on the light-induced toxicity of Brachionus plicatilis were studied. The main methods and experimental results were as follows: (1) The semi-lethal concentration of anthracene in UV light was much lower than that in normal light, The rotifers have significant light-induced acute toxicity. (2) Under UV irradiation, anthracene could induce the increase of ROS and MDA content in B. plicatilis, and the activity of antioxidant enzymes in B. plicatilis significantly changed, Where SOD, GPx activity was induced within 24 hours of the beginning of the experiment. And the content of GPX and CAT was inhibited after 48 hours. Therefore, the anthracite stress induced by UV radiation could more strongly interfere with the ant oxidative metabolism of B. plicatilis, and more seriously cause oxidative damage, significant light-induced toxicity.

  12. Application of rotifer Brachionus plicatilis in detecting the toxicity of harmful algae

    Science.gov (United States)

    Yan, Tian; Wang, Yunfeng; Wang, Liping; Chen, Yang; Han, Gang; Zhou, Mingjiang

    2009-05-01

    The toxicity of seven major HAB (harmful algal bloom) species/strains, Prorocentrum donghaiense, Phaeocystis globosa, Prorocentrum micans, Alexandrium tamarense (AT-6, non-PSP producer), Alexandrium lusitanicum, Alexandrum tamarense (ATHK) and Heterosigma akashiwo were studied against rotifer Brachionus plicatilis under laboratory conditions. The results show that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6), or A. lusitanicum could maintain the individual survival and reproduction, as well as the population increase of the rotifer, but the individual reproduction would decrease when exposed to these five algae at higher densities for nine days; H. akashiwo could decrease the individual survival and reproduction, as well as population increase of the rotifer, which is similar to that of the starvation group, indicating that starvation might be its one lethal factor except for the algal toxins; A. tamarense (ATHK) has strong lethal effect on the rotifer with 48h LC50 at 800 cells/mL. The experiment on ingestion ability indicated by gut pigment change shows that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6) and A. lusitanicum can be taken by the rotifers as food, but A. tamarense (ATHK) or H. akashiwo can be ingested by the rotifers. The results indicate that all the indexes of individual survival and reproduction, population increase, gut pigment change of the rotifers are good and convenient to be used to reflect the toxicities of HAB species. Therefore, rotifer is suggested as one of the toxicity testing organisms in detecting the toxicity of harmful algae.

  13. Estimating the toxicity of ambient fine aerosols using freshwater rotifer Brachionus calyciflorus (Rotifera: Monogononta).

    Science.gov (United States)

    Verma, Vishal; Rico-Martinez, Roberto; Kotra, Neel; Rennolds, Corey; Liu, Jiumeng; Snell, Terry W; Weber, Rodney J

    2013-11-01

    The toxicity of atmospheric fine particulate matter (PM2.5) in Atlanta is assessed using freshwater rotifers (Brachionus calyciflorus). The PM-laden quartz filters were extracted in both water and methanol. Aerosol extracts were passed through a C-18 column to separate the PM components into hydrophobic and hydrophilic fractions. Toxicity data reported in the units of LC50 (concentration that kills 50% of the test population in 24 h) shows that ambient particles are toxic to the rotifers with LC50 values ranging from 5 to 400 μg of PM. The methanol extract of the aerosols was substantially more toxic (8 ± 6 times) to the rotifers compared to the water extracts. A sizeable fraction (>70%) of toxicity was found to be associated with the hydrophobic fraction of PM. However, none of the bulk aerosol species was strongly correlated with the LC50 values suggesting a complicated mechanism of toxicity probably involving synergistic interactions of various PM components. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Morphology and ultrastructure of the freshwater rotifer Brachionus bidentatus (Monogononta: Brachionidae) using scanning and transmission electron microscopy.

    Science.gov (United States)

    Guerrero-Jiménez, Gerardo; Zavala-Padilla, Guadalupe; Silva-Briano, Marcelo; Rico-Martínez, Roberto

    2013-12-01

    The study of sexual reproductive behavior supported by ultrastructural evidence is important in rotifers to describe differences among potential cryptic species. In this research, the morphology of the rotifer Brachionus bidentatus is described at the ultrastructural level, using electronic microscopy, together with a brief description and discussion of its sexual reproductive behavior. The characteristics of the (a) male, (b) the female, (c) the sexual egg or cyst, (d) the partenogenic egg, (e) the no-fecundated sexual egg (male egg), and (f) the trophi, were described. Another part of this research is dedicated to the ultrastructure of the sex cells of the male rotifer B. bidentatus. Samples were obtained from La Punta pond in Cosio, Aguascalientes, Mexico (22 degrees 08' N - 102 degrees 24' W), and a culture was maintained in the laboratory. Fifty organisms, from different stages of the rotifer Brachionus bidentatus, were fixed in Formol at 4% and then prepared; besides, for the trophi, 25 female rotifer Brachionus bidentatus were prepared for observation in a JEOL 5900 LV scanning electronic microscope. In addition, for the observation of male sex cells, 500 males of Brachionus bidentatus were isolated, fixed and observed in a JEOL 1010 transmission microscope. Females of B. bidentatus in laboratory cultures had a lifespan of five days (mean+one SD = 4.69 +/- 0.48; N=13), and produced 4.5 +/- 3.67 (N=6) parthenogenetic eggs during such lifespan. In the case of non-fertilized sexual eggs, they produced up to 18 eggs (mean+one SD = 13 +/- 4.93; N=7). Sexual females produced a single cyst on average (mean +/- one SD = I +/- 0; N=20). For the sexual cycle, the time of copulation between male and female ranged from 10 to 40 seconds (mean +/- one SD = 17.33 +/- 10.55, N=7). The spermatozoa are composed of a celular body and a flagellum, the size of the body is of 300 nm while the flagellum measures 1 700nm. The rods have a double membrane. Their mean length is almost

  15. Analysis of expressed sequence tags of the cyclically parthenogenetic rotifer Brachionus plicatilis.

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    Koushirou Suga

    Full Text Available BACKGROUND: Rotifers are among the most common non-arthropod animals and are the most experimentally tractable members of the basal assemblage of metazoan phyla known as Gnathifera. The monogonont rotifer Brachionus plicatilis is a developing model system for ecotoxicology, aquatic ecology, cryptic speciation, and the evolution of sex, and is an important food source for finfish aquaculture. However, basic knowledge of the genome and transcriptome of any rotifer species has been lacking. METHODOLOGY/PRINCIPAL FINDINGS: We generated and partially sequenced a cDNA library from B. plicatilis and constructed a database of over 2300 expressed sequence tags corresponding to more than 450 transcripts. About 20% of the transcripts had no significant similarity to database sequences by BLAST; most of these contained open reading frames of significant length but few had recognized Pfam motifs. Sixteen transcripts accounted for 25% of the ESTs; four of these had no significant similarity to BLAST or Pfam databases. Putative up- and downstream untranslated regions are relatively short and AT rich. In contrast to bdelloid rotifers, there was no evidence of a conserved trans-spliced leader sequence among the transcripts and most genes were single-copy. CONCLUSIONS/SIGNIFICANCE: Despite the small size of this EST project it revealed several important features of the rotifer transcriptome and of individual monogonont genes. Because there is little genomic data for Gnathifera, the transcripts we found with no known function may represent genes that are species-, class-, phylum- or even superphylum-specific; the fact that some are among the most highly expressed indicates their importance. The absence of trans-spliced leader exons in this monogonont species contrasts with their abundance in bdelloid rotifers and indicates that the presence of this phenomenon can vary at the subphylum level. Our EST database provides a relatively large quantity of transcript

  16. Genome size evolution at the speciation level: the cryptic species complex Brachionus plicatilis (Rotifera).

    Science.gov (United States)

    Stelzer, Claus-Peter; Riss, Simone; Stadler, Peter

    2011-04-07

    Studies on genome size variation in animals are rarely done at lower taxonomic levels, e.g., slightly above/below the species level. Yet, such variation might provide important clues on the tempo and mode of genome size evolution. In this study we used the flow-cytometry method to study the evolution of genome size in the rotifer Brachionus plicatilis, a cryptic species complex consisting of at least 14 closely related species. We found an unexpectedly high variation in this species complex, with genome sizes ranging approximately seven-fold (haploid '1C' genome sizes: 0.056-0.416 pg). Most of this variation (67%) could be ascribed to the major clades of the species complex, i.e. clades that are well separated according to most species definitions. However, we also found substantial variation (32%) at lower taxonomic levels--within and among genealogical species--and, interestingly, among species pairs that are not completely reproductively isolated. In one genealogical species, called B. 'Austria', we found greatly enlarged genome sizes that could roughly be approximated as multiples of the genomes of its closest relatives, which suggests that whole-genome duplications have occurred early during separation of this lineage. Overall, genome size was significantly correlated to egg size and body size, even though the latter became non-significant after controlling for phylogenetic non-independence. Our study suggests that substantial genome size variation can build up early during speciation, potentially even among isolated populations. An alternative, but not mutually exclusive interpretation might be that reproductive isolation tends to build up unusually slow in this species complex.

  17. Genome size evolution at the speciation level: The cryptic species complex Brachionus plicatilis (Rotifera

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    Riss Simone

    2011-04-01

    Full Text Available Abstract Background Studies on genome size variation in animals are rarely done at lower taxonomic levels, e.g., slightly above/below the species level. Yet, such variation might provide important clues on the tempo and mode of genome size evolution. In this study we used the flow-cytometry method to study the evolution of genome size in the rotifer Brachionus plicatilis, a cryptic species complex consisting of at least 14 closely related species. Results We found an unexpectedly high variation in this species complex, with genome sizes ranging approximately seven-fold (haploid '1C' genome sizes: 0.056-0.416 pg. Most of this variation (67% could be ascribed to the major clades of the species complex, i.e. clades that are well separated according to most species definitions. However, we also found substantial variation (32% at lower taxonomic levels - within and among genealogical species - and, interestingly, among species pairs that are not completely reproductively isolated. In one genealogical species, called B. 'Austria', we found greatly enlarged genome sizes that could roughly be approximated as multiples of the genomes of its closest relatives, which suggests that whole-genome duplications have occurred early during separation of this lineage. Overall, genome size was significantly correlated to egg size and body size, even though the latter became non-significant after controlling for phylogenetic non-independence. Conclusions Our study suggests that substantial genome size variation can build up early during speciation, potentially even among isolated populations. An alternative, but not mutually exclusive interpretation might be that reproductive isolation tends to build up unusually slow in this species complex.

  18. Optofluidic technology for monitoring rotifer Brachionus calyciflorus responses to regular light pulses

    Science.gov (United States)

    Cartlidge, Rhys; Campana, Olivia; Nugegoda, Dayanthi; Wlodkowic, Donald

    2016-12-01

    Behavioural alterations can occur as a result of a toxicant exposure at concentrations significantly lower than lethal effects that are commonly measured in acute toxicity testing. The use of alternating light and dark photoperiods to test phototactic responses of aquatic invertebrates in the presence of environmental contaminants provides an attractive analytical avenue. Quantification of phototactic responses represents a sublethal endpoint that can be employed as an early warning signal. Despite the benefits associated with the assessment of these endpoints, there is currently a lack of automated and miniaturized bioanalytical technologies to implement the development of toxicity testing with small aquatic species. In this study we present a proof-of-concept microfluidic Lab-on-a-Chip (LOC) platform for the assessment of rotifer swimming behavior in the presence of the toxicant copper sulfate. The device was designed to assess impact of toxicants at sub-lethal concentrations on freshwater crustacean Brachionus calyciflorus, testing behavioral endpoints such as animal swimming distance, speed and acceleration. The LOC device presented in this work enabled straightforward caging of microscopic crustaceans as well as non-invasive analysis of rapidly swimming animals in a focal plane of a video-microscopy system. The chip-based technology was fabricated using a new photolithography method that enabled formation of thick photoresist layers with minimal distortion. Photoresist molds were then employed for replica molding of LOC devices with poly(dimethylsiloxane) (PDMS) elastomer. The complete bioanalytical system consisted of: (i) microfluidic PDMS chip-based device; (ii) peristaltic microperfusion pumping manifold; (iii) miniaturized CMOS camera for video data acquisition; and (iv) video analysis software algorithms for quantification of changes in swimming behaviour of B. calyciflorus in response to reference toxicants.

  19. Efficacy of a commercial probiotic relative to oxytetracycline as Gram-negative bacterial control agents in a rotifer (Brachionus plicatilis) batch culture

    Science.gov (United States)

    Two trials were conducted to evaluate two gram-negative bacterial control strategies in batch cultures of the rotifer Brachionus plicatilis. In the first trial, rotifers at an initial density of 47/mL were cultured for 5 d and dosed with a 10-mg/L solution of either oxytetracycline or a commercial p...

  20. Whole-mount in situ hybridization in the Rotifer Brachionus plicatilis representing a basal branch of lophotrochozoans

    Science.gov (United States)

    Boell, Louis A.

    2008-01-01

    In order to broaden the comparative scope of evolutionary developmental biology and to refine our picture of animal macroevolution, it is necessary to establish new model organisms, especially from previously underrepresented groups, like the Lophotrochozoa. We have established the culture and protocols for molecular developmental biology in the rotifer species Brachionus plicatilis Müller (Rotifera, Monogononta). Rotifers are nonsegmented animals with enigmatic basal position within the lophotrochozoans and marked by several evolutionary novelties like the wheel organ (corona), the median eye, and the nonpaired posterior foot. The expression of Bp-Pax-6 is shown using whole-mount in situ hybridization. The inexpensive easy culture and experimental tractability of Brachionus as well as the range of interesting questions to which it holds the key make it a promising addition to the “zoo” of evo-devo model organisms. Electronic supplementary material The online version of this article (doi:10.1007/s00427-008-0234-z) contains supplementary material, which is available to authorized users. PMID:18594859

  1. Comparative ecotoxicity of interstitial waters in littoral ecosystems using Microtox{reg_sign} and the rotifer Brachionus plicatilis

    Energy Technology Data Exchange (ETDEWEB)

    Valls, T.A. Del; Forja, J.M. [Univ. de Cadiz (Spain). Dpto. de Quimica Fisica; Lubian, L.M.; Gomez-Parra, A. [C.S.I.C., Cadiz (Spain). Inst. de Ciencias Marinas de Andalucia

    1997-11-01

    The toxic effects of sediment interstitial waters collected from seven littoral sites in the Gulf of Cadiz were tested with the Microtox assay and a 7-d Brachionus plicatilis (Rotifera) decline test. Dissolved organic carbon (DOC), nutrients (ammonia, phosphate, nitrate, nitrite, and silicate), the heavy metals (Fe, Mn, Zn, Cu, Pb, Cr, and Cd), and the linear alkylbenzensulfonate (LAS) concentrations in the interstitial water were measured. The results of assays were compared in a dose-response relationship between sites. This comparison has demonstrated a general agreement between toxicity values determined by Brachionus plicatilis and Photobacterium phosphoreum, except in the case of interstitial water toxicity from mixtures of heavy metals. Data derived from interstitial water chemistry and bioassays were assembled by multivariate statistical techniques (principal components analysis). Positive prevalence of these components in cases studied was used to establish those ranges in chemical concentrations associated with adverse effects. The interstitial water guidelines, in terms of concentrations at or below which biological effects have been shown to be minimal (mg/L), are: DOC, 12.8; phosphate, 0.28; LAS, 80.4; ammonia, 12.1: chromium, 0.0045.

  2. Discovering genes associated with dormancy in the monogonont rotifer Brachionus plicatilis

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    Kube Michael

    2009-03-01

    Full Text Available Abstract Background Microscopic monogonont rotifers, including the euryhaline species Brachionus plicatilis, are typically found in water bodies where environmental factors restrict population growth to short periods lasting days or months. The survival of the population is ensured via the production of resting eggs that show a remarkable tolerance to unfavorable conditions and remain viable for decades. The aim of this study was to generate Expressed Sequence Tags (ESTs for molecular characterisation of processes associated with the formation of resting eggs, their survival during dormancy and hatching. Results Four normalized and four subtractive libraries were constructed to provide a resource for rotifer transcriptomics associated with resting-egg formation, storage and hatching. A total of 47,926 sequences were assembled into 18,000 putative transcripts and analyzed using both Blast and GO annotation. About 28–55% (depending on the library of the clones produced significant matches against the Swissprot and Trembl databases. Genes known to be associated with desiccation tolerance during dormancy in other organisms were identified in the EST libraries. These included genes associated with antioxidant activity, low molecular weight heat shock proteins and Late Embryonic Abundant (LEA proteins. Real-time PCR confirmed that LEA transcripts, small heat-shock proteins and some antioxidant genes were upregulated in resting eggs, therefore suggesting that desiccation tolerance is a characteristic feature of resting eggs even though they do not necessarily fully desiccate during dormancy. The role of trehalose in resting-egg formation and survival remains unclear since there was no significant difference between resting-egg producing females and amictic females in the expression of the tps-1 gene. In view of the absence of vitellogenin transcripts, matches to lipoprotein lipase proteins suggest that, similar to the situation in dipterans, these

  3. Moderately lower temperatures greatly extend the lifespan of Brachionus manjavacas (Rotifera): Thermodynamics or gene regulation?

    Science.gov (United States)

    Johnston, Rachel K; Snell, Terry W

    2016-06-01

    Environmental temperature greatly affects lifespan in a wide variety of animals, but the exact mechanisms underlying this effect are still largely unknown. A moderate temperature decrease from 22°C to 16°C extends the lifespan of the monogonont rotifer Brachionus manjavacas by up to 163%. Thermodynamic effects on metabolism contribute to this increase in longevity, but are not the only cause. When rotifers are exposed to 16°C for four days and then transfered to 22°C, they survive until day 13 at nearly identical rates as rotifers maintained at 16°C continuously. This persistence of the higher survival for nine days after transfer to 22°C suggests that low temperature exposure alters the expression of genes that affect the rate of aging. The relative persistence of the gene regulation effect suggests that it may play an even larger role in slowing aging than the thermodynamic effects. The life extending effects of these short-term low temperature treatments are largest when the exposure happens early in the life cycle, demonstrating the importance of early development. There is no advantage to lowering the temperature below 16°C to 11° or 5°C. Rotifers exposed to 16°C also displayed increased resistance to heat, starvation, oxidative and osmotic stress. Reproductive rates at 16°C were lower than those at 22°C, but because they reproduce longer, there is no significant change in the lifetime fecundity of females. To investigate which genes contribute to these effects, the expression of specific temperature sensing genes was knocked down using RNAi. Of 12 genes tested, RNAi knockdown of four eliminated the survival enhancing effects of the four-day cold treatment: TRP7, forkhead box C, Y-box factor, and ribosomal protein S6. This demonstrates that active gene regulation is an important factor in temperature mediated life extension, and that these particular genes play an integral role in these pathways. As a thermoresponsive sensor, TRP7 may be

  4. Use of Copper to Selectively Inhibit Brachionus calyciflorus (Predator) Growth in Chlorella kessleri (Prey) Mass Cultures for Algae Biodiesel Production.

    Science.gov (United States)

    Pradeep, Vishnupriya; Van Ginkel, Steven W; Park, Sichoon; Igou, Thomas; Yi, Christine; Fu, Hao; Johnston, Rachel; Snell, Terry; Chen, Yongsheng

    2015-08-31

    A single Brachionus rotifer can consume thousands of algae cells per hour causing an algae pond to crash within days of infection. Thus, there is a great need to reduce rotifers in order for algal biofuel production to become reality. Copper can selectively inhibit rotifers in algae ponds, thereby protecting the algae crop. Differential toxicity tests were conducted to compare the copper sensitivity of a model rotifer-B. calyciflorus and an alga, C. kessleri. The rotifer LC50 was <0.1 ppm while the alga was not affected up to 5 ppm Cu(II). The low pH of the rotifer stomach may make it more sensitive to copper. However, when these cultures were combined, a copper concentration of 1.5 ppm was needed to inhibit the rotifer as the alga bound the copper, decreasing its bioavailability. Copper (X ppm) had no effect on downstream fatty acid methyl ester extraction.

  5. Use of Copper to Selectively Inhibit Brachionus calyciflorus (Predator Growth in Chlorella kessleri (Prey Mass Cultures for Algae Biodiesel Production

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    Vishnupriya Pradeep

    2015-08-01

    Full Text Available A single Brachionus rotifer can consume thousands of algae cells per hour causing an algae pond to crash within days of infection. Thus, there is a great need to reduce rotifers in order for algal biofuel production to become reality. Copper can selectively inhibit rotifers in algae ponds, thereby protecting the algae crop. Differential toxicity tests were conducted to compare the copper sensitivity of a model rotifer—B. calyciflorus and an alga, C. kessleri. The rotifer LC50 was <0.1 ppm while the alga was not affected up to 5 ppm Cu(II. The low pH of the rotifer stomach may make it more sensitive to copper. However, when these cultures were combined, a copper concentration of 1.5 ppm was needed to inhibit the rotifer as the alga bound the copper, decreasing its bioavailability. Copper (X ppm had no effect on downstream fatty acid methyl ester extraction.

  6. Morphology and ultrastructure of the freshwater rotifer Brachionus bidentatus (Monogononta: Brachionidae using scanning and transmission electron microscopy

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    Gerardo Guerrero-Jiménez

    2013-12-01

    Full Text Available The study of sexual reproductive behavior supported by ultrastructural evidence is important in rotifers to describe differences among potential cryptic species. In this research, the morphology of the rotifer Brachionus bidentatus is described at the ultrastructural level, using electronic microscopy, together with a brief description and discussion of its sexual reproductive behavior. The characteristics of the (a male,(b the female, (c the sexual egg or cyst, (d the partenogenic egg, (e the no-fecundated sexual egg (male egg, and (f the trophi, were described. Another part of this research is dedicated to the ultrastructure of the sex cells of the male rotifer B. bidentatus. Samples were obtained from La Punta pond in Cosio, Aguascalientes, Mexico (22°08’ N - 102°24’ W, and a culture was maintained in the laboratory. Fifty organisms, from different stages of the rotifer Brachionus bidentatus, were fixed in Formol at 4% and then prepared; besides, for the trophi, 25 female rotifer Brachionus bidentatus were prepared for observation in a JEOL 5900 LV scanning electronic microscope. In addition, for the observation of male sex cells, 500 males of Brachionus bidentatus were isolated, fixed and observed in a JEOL 1010 transmission microscope. Females of B. bidentatus in laboratory cultures had a lifespan of five days (mean±one SD=4.69±0.48; N=13, and produced 4.5+3.67 (N=6 parthenogenetic eggs during such lifespan. In the case of non-fertilized sexual eggs, they produced up to 18 eggs (mean±one SD=13±4.93; N=7. Sexual females produced a single cyst on average (mean±one SD=1±0; N=20. For the sexual cycle, the time of copulation between male and female ranged from 10 to 40 seconds (mean±one SD=17.33±10.55, N=7. The spermatozoa are composed of a celular body and a flagellum, the size of the body is of 300nm while the flagellum measures 1 700nm. The rods have a double membrane. Their mean length is almost 2.45µm±0.74, N=6; and their

  7. Bacterial diversity associated with the rotifer Brachionus plicatilis sp. complex determined by culture-dependent and -independent methods.

    Science.gov (United States)

    Ishino, Ryota; Iehata, Shunpei; Nakano, Miyo; Tanaka, Reiji; Yoshimatsu, Takao; Maeda, Hiroto

    2012-03-01

    The bacterial communities associated with rotifers (Brachionus plicatilis sp. complex) and their culture water were determined using culture-dependent and -independent methods (16S rRNA gene clone library). The bacterial communities determined by the culture-independent method were more diverse than those determined by the culture-dependent method. Although the culture-dependent method indicated the bacterial community of rotifers was relatively similar to that of the culture water, 16S rRNA gene clone library analyses revealed a great difference between the two microbiotas. Our results suggest that most bacteria associated with rotifers are not easily cultured using conventional methods, and that the microbiota of rotifers do not correspond with that of the culture water completely.

  8. Two circular chromosomes of unequal copy number make up the mitochondrial genome of the rotifer Brachionus plicatilis.

    Science.gov (United States)

    Suga, Koushirou; Mark Welch, David B; Tanaka, Yukari; Sakakura, Yoshitaka; Hagiwara, Atsushi

    2008-06-01

    The monogonont rotifer Brachionus plicatilis is an emerging model system for a diverse array of questions in limnological ecosystem dynamics, the evolution of sexual recombination, cryptic speciation, and the phylogeny of basal metazoans. We sequenced the complete mitochondrial genome of B. plicatilis sensu strictu NH1L and found that it is composed of 2 circular chromosomes, designated mtDNA-I (11,153 bp) and mtDNA-II (12,672 bp). Hybridization to DNA isolated from mitochondria demonstrated that mtDNA-I is present at 4 times the copy number of mtDNA-II. The only nucleotide similarity between the 2 chromosomes is a 4.9-kbp region of 99.5% identity including a transfer RNA (tRNA) gene and an extensive noncoding region that contains putative D-loop and control sequence. The mtDNA-I chromosome encodes 4 proteins (ATP6, COB, NAD1, and NAD2), 13 tRNAs, and the large and small subunit ribosomal RNAs; mtDNA-II encodes 8 proteins (COX1-3, NAD3-6, and NAD4L) and 9 tRNAs. Gene order is not conserved between B. plicatilis and its closest relative with a sequenced mitochondrial genome, the acanthocephalan Leptorhynchoides thecatus, or other sequenced mitochondrial genomes. Polymerase chain reaction assays and Southern hybridization to DNA from 18 strains of Brachionus suggest that the 2-chromosome structure has been stable for millions of years. The novel organization of the B. plicatilis mitochondrial genome into 2 nearly equal chromosomes of 4-fold different copy number may provide insight into the evolution of metazoan mitochondria and the phylogenetics of rotifers and other basal animal phyla.

  9. Sublethal gamma irradiation affects reproductive impairment and elevates antioxidant enzyme and DNA repair activities in the monogonont rotifer Brachionus koreanus

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jeonghoon; Won, Eun-Ji [Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Il-Chan; Yim, Joung Han [Division of Life Sciences, Korea Polar Research Institute, Incheon 406-840 (Korea, Republic of); Lee, Su-Jae [Department of Life Science, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Lee, Jae-Seong, E-mail: jslee2@skku.edu [Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2014-10-15

    Highlights: • No mortality within 96 h even at a high intensity (1200 Gy). • A reduced fecundity of Brachionus koreanus at over 150 Gy with a decrease in lifespan. • Dose-dependent ROS increase with GST enzyme activity at sub-lethal doses. • Significant impact on life table parameters, particularly fecundity. • Significant up-regulation of DNA repair-associated genes at sublethal doses. - Abstract: To examine the effects of gamma radiation on marine organisms, we irradiated several doses of gamma ray to the microzooplankton Brachionus koreanus, and measured in vivo and in vitro endpoints including the survival rate, lifespan, fecundity, population growth, gamma ray-induced oxidative stress, and modulated patterns of enzyme activities and gene expressions after DNA damage. After gamma radiation, no individuals showed any mortality within 96 h even at a high intensity (1200 Gy). However, a reduced fecundity (e.g. cumulated number of offspring) of B. koreanus at over 150 Gy was observed along with a slight decrease in lifespan. At 150 Gy and 200 Gy, the reduced fecundity of the rotifers led to a significant decrease in population growth, although in the second generation the population growth pattern was not affected even at 200 Gy when compared to the control group. At sub-lethal doses, reactive oxygen species (ROS) levels dose-dependently increased with GST enzyme activity. In addition, up-regulations of the antioxidant and chaperoning genes in response to gamma radiation were able to recover cellular damages, and life table parameters were significantly influenced, particularly with regard to fecundity. DNA repair-associated genes showed significantly up-regulated expression patterns in response to sublethal doses (150 and 200 Gy), as shown in the expression of the gamma-irradiated B. koreanus p53 gene, suggesting that these sublethal doses were not significantly fatal to B. koreanus but induced DNA damages leading to a decrease of the population size.

  10. Short-term harmful effects of unionised ammonia on natural populations of Moina micrura and Brachionus rubens in a deep waste treatment pond.

    Science.gov (United States)

    Arauzo, M; Valladolid, M

    2003-06-01

    Populations of Moina micrura and Brachionus rubens in a deep waste treatment pond were exposed to the natural short-term fluctuations of unionised ammonia (90-min intervals of monitoring) that occur in the course of a day during a summer algal bloom. Under natural conditions, three replicate experiments were conducted in which water temperature, pH, dissolved oxygen, total ammonia, unionised ammonia, phytoplankton biomass and zooplankton (number of living and dead organisms, mortality rate and instant mortality) were studied. The time-course of unionised ammonia concentration was consistent with those shown by temperature, pH, phytoplankton biomass, dissolved oxygen, Moina micrura mortality and Brachionus rubens mortality. On the other hand, temperature, pH and dissolved oxygen never exceeded the tolerance ranges described for Moina and Brachionus, which led us to attribute the cause of zooplankton mortality to unionised ammonia toxicity. Mortality rates of 63%, 27% and 34% were recorded for Moina in each replicate experiment. Brachionus was less affected, with mortalities of 7.3%, 6.2% and 6.0%. These results confirm previous field observations (Water Res. 34(14) (2000) 3666; Water Res. 37(5) (2003) 1048) that attributed a reduction in zooplankton biomass during certain periods of summer (algal blooms) to a harmful side-effect of an excessive increase in phytoplankton biomass: high photosynthetic activity during these periods of proliferation of algae gives rise to an increased pH (>/=8) and, subsequently, leads to production of unionised ammonia (toxic for aquatic organisms) from its ionised fraction.

  11. Population dynamics of Brachionus calyciflorus (Rotifera: Brachionidae in waste water from food-processing industry in Mexico

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    Raymundo Alfredo Arévalo Stevenson

    1998-09-01

    Full Text Available Waste water from Mexico's largest food processing industrial sector (based on maize, nejayote water was used for growing Brachionus calyciflorus isolated from Lake Chapultepec in the Federal District of Mexico (D.F.. Nejayote water was collected from Colonia Providencia, D.F. Experiments were conducted at 25°C in 25 ml capacity vials with 20 ml of medium into which we introduced B. calyciflorus at an initial density of 1 ind ml-1. The experimental design consisted a total of 33 test vessels (2 food combinations X 5 densities X 3 replicates = 30 plus 3 replicates as controls that contained only algae. Experiments were terminated after day 16. Waste water in original concentration did nt rotifes. However, when diluted to 5 oncentrations (ranging from 2% to 32% and pH adjusted to 7.0, rotifer density increased with increasing concentration of waste water. Green algae (at constant density of 2 X 10 6 cells-1 of Chlorella in combination with waste water resulted in a higher abundance of rotifers only at higher concentration (above 8 % of waste water. The maximum peak density of rotifers (238-50 ind ml -1 was obtained at 16% dilution of waste water nd with addition of Chlorella. The rate of population increase per day ® (mean-SD varied from 0.355-0.059 to 0.457-0.048 depending on food combination and concetration.Se usó aguas de desecho de la industria de la masa y la tortilla (aguas de nixtamal o nejayote para crecer rotíferos de agua dulce, Brachionus calyciflorus. El nejayote sin dilución no permitió el desarrollo del rotífero. Sin embargo, cuando se diluyó, B. calyciflorus aprovechó la materia orgánica. El agua de desecho por sí misma (sin alimento algal adicional fue comparable al agua con densidades del alga Chlorella de 2 X 10(6 células ml-1. Concentraciones de nejayote por encima del 8% no permitieron el crecimiento poblacional. Sin embargo, la presencia de alga permitió el desarrollo del rotífero a concentraciones de 8% y 16

  12. Improvement of the nutritional value and growth of rotifer (Brachionus plicatilis by different enrichment period with Bacillus sp.

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    Sutia Budi

    2011-01-01

    Full Text Available Brachionus plicatilis is a widely used as natural feed in hatchery. Characteristics of rotifers as biocapsule can improve the quality of rotifers in a practical way. Bacillus sp. is capable of improving the nutrition rotifers to produce vitamins, food detoxication or through enzymatic activity such as protease, lipase, and amylase. This research aimed at observing the influence of the enrichment length of Bacillus sp. on the quality of nutrition and growth of rotifers. The research container was a polyearbonate vessel of one ton volume which contained Nannochloropsis sp. with the density of 105 cell/mL, it was then scattered with rotifer with the density of 1,000 ind./mL. The types of bacteria used were Bacillus subtilis, B. pumilus and B. licheformis with the density of 2x1010 cfu/g. The experiments tried with different enrichment length were A = 0 hour, B = 5 hours, C = 10 hours and D = 10 hours with triplicate. As the comparing data, rotifer culture experiment was carried out with Nannochlorophsis sp.as the control. The number of containers were 24 which consists of 12 for threatment and 12 pieces as control. Variables measured were proximate to each treatment and the growth of rotifers. The result of the research revealed the enrichment length of rotifers with Bacillus sp. has significantly (P Key words: rotifers, Bacillus, enrichment period, proximate   ABSTRAK Brachionus plicatilis merupakan pakan alami yang banyak digunakan dalam pembenihan. Karakteristik rotifer sebagai biokapsul secara praktis dapat meningkatkan kualitas rotifer. Bacillus sp. mampu memperbaiki nutrisi rotifer dengan memproduksi vitamin, detoksikasi pangan maupun melalui aktivitas enzimatis seperti protease, lipase, dan amilase. Penelitian ini bertujuan untuk melihat pengaruh pengkayaan Bacillus sp. terhadap kualitas nutrisi dan pertumbuhan rotifer. Wadah penelitian menggunakan bak fiber volume 1 ton yang berisikan Nannochloropsis sp. dengan kepadatan 105 cell

  13. Experimental study on the interspecific interactions between the two bloom-forming algal species and the rotifer Brachionus plicatilis

    Science.gov (United States)

    Xie, Zhihao; Xiao, Hui; Tang, Xuexi; Cai, Hengjiang

    2009-06-01

    The interspecific interactions between the rotifer Brachionus plicatilis and two harmful algal blooms (HAB) species were investigated experimentally by single culture method. B. plicatilis population and the growth of the two algae were compared at different algal cell densities. The results demonstrated that the B. plicatilis obtained sufficient nutrition from Prorocentrum donghaiense to support net population increase. With exposure to 2.5×104 cells mL-1 of P. donghaiense, the number of B. plicatilis increased faster than it did when exposed to other four algal densities (5, 10, 15 and 20 ×104 cells mL-1), and the increase rate of B. plicatilis population ( r) at this algal density was 0.104 ± 0.015 rd-1. Cell densities of P. donghaiense decreased due to the grazing of B. plicatilis. In contrast, Heterosigma akashiwo had an adverse effect on B. plicatilis population and its growth was largely unaffected by rotifer grazing. In this case, B. plicatilis population decreased and H. akashiwo grew at a rate similar to that of the control.

  14. Morphological alterations in the freshwater rotifer Brachionus calyciflorus Pallas 1766 (Rotifera: Monogononta) caused by vinclozolin chronic exposure.

    Science.gov (United States)

    Alvarado-Flores, Jesús; Rico-Martínez, Roberto; Adabache-Ortíz, Araceli; Silva-Briano, Marcelo

    2015-05-01

    Vinclozolin (VZ) is a dicarboximide fungicide widely used on fruits, vegetables and wines, effective against fungi plagues. In this study we characterized the effects of VZ using a 4-day reproductive chronic assay with the freshwater rotifer Brachionus calyciflorus. The assay included observations of several features of asexual and sexual reproduction. Our results indicate that VZ: (a) increased asexual and sexual reproduction, (b) caused severe abnormality in females and (c) these abnormalities were inherited by sexual and asexual reproduction. At 1.2 mg/L three abnormal females were found out of 457 total females (0.66 %). This low percentage is consistent and reproducible according to further analysis, where we increased the number of replicates and total females exposed to 1.2 mg/L of VZ, and found 18 abnormal females out of 2868 total females (0.63 % abnormality). Interestingly, abnormal females found at 5.6 mg/L VZ exposure, were able to show mating behavior. Our results suggest that VZ behaves as a strong endocrine disruptor whose effects show the characteristic inverted-U-shape exposure concentration response curve regarding the intrinsic population increase and the percentage of abnormalities as endpoints.

  15. Successful Replacement of Artemia salina nauplii with Marine Rotifers (Brachionus plicatilis) in the Diet of Preadult Zebrafish (Danio rerio).

    Science.gov (United States)

    Lawrence, Christian; James, Althea; Mobley, Scottie

    2015-10-01

    Previously established rearing protocols for zebrafish begin feeding with marine rotifers (Brachionus plicatilis), followed by Artemia nauplii until the fish reach subadult stage, the developmental time point at which they can be most easily transitioned onto a processed diet. However, the inclusion of Artemia is less than ideal, given its fluctuating availability and high costs. We tested whether or not we could replace Artemia with rotifers during our normal rearing sequence and still meet published performance standards for (i) weaning fish onto a processed diet by 25 days postfertilization (dpf) and (ii) successful breeding by 60 dpf. Here, we present the results of trials where wild-type and casper zebrafish were fed exclusively with rotifers (R) or rotifers followed by Artemia (RA) for the first 25 dpf after which point all fish were transitioned to a processed diet (Gemma Micro 300). We measured growth and survival at days 25 and 60, and tested for reproductive capability at 60 dpf. While growth performance was significantly better in the RA groups, we were still able to meet goals for both weaning and generation time in the R groups without compromising survival or sex ratios.

  16. Demography of zooplankton (Anuraeopsis fissa, Brachionus rubens and Moina macrocopa fed Chlorella vulgaris and Scenedesmus acutus cultured on different media

    Directory of Open Access Journals (Sweden)

    Jesús Morales-Ventura

    2012-09-01

    Full Text Available Generally zooplankton growth is often limited by the quality of their algal diet. A cheaper common practice in aquaculture, is to culture algae with fertilizers; however, the demography of zooplankton when fed these algae has not yet been evaluated. We studied the population growth and life table demography of the rotifers Anuraeopsis fissa and Brachionus rubens, and the cladoceran Moina macrocopa. For this, the algae Scenedesmus acutus or Chlorella vulgaris were cultured on defined (Bold’s basal medium or the commercial liquid fertilizer (Bayfolan. Experiments were conducted at one algal concentration 1.0x10(6cells/mL of C. vulgaris or its equivalent dry weight of 0.5x10(6cells/mL of S. acutus. The population dynamics were tested at 23±1ºC in 100mL transparent jars, each with 50mL of the test medium, with an initial density of 0.5indiv/mL, for a total of 48 test jars (3 zooplankton 2 algal species x 2 culture media x 4 replicates. For the life table experiments with M. macrocopa, we introduced 10 neonates (Generalmente el crecimiento del zooplancton está a menudo limitado por la calidad de su dieta de algas. La demografía del zooplancton durante la alimentación con algas no ha sido estudiada, a pesar de que el cultivo de algas con fertilizantes es una práctica económica común en acuacultura. Se analizó la demografía de Anuraeopsis fissa y Brachionus rubens (rotíferos y Moina macrocopa (cladóceros, alimentados con las algas verdes Scenedesmus acutus o Chlorella vulgaris cultivadas en medio Bold o fertilizante líquido comercial (Bayfolan, de Bayer. En los rotíferos no se observaron diferencias significativas en el promedio de vida, sin embargo, este parámetro en M. macrocopa con S. acutus cultivada en Medio Bold, fue significativamente menor que en otras dietas. Las tasas de reproducción bruta y neta de A. fissa fueron significativamente mayores con C. vulgaris cultivada en medio Bold, que con el fertilizante; estas tasas en B

  17. Changes in the expression of four heat shock proteins during the aging process in Brachionus calyciflorus (rotifera).

    Science.gov (United States)

    Yang, Jianghua; Mu, Yawen; Dong, Siming; Jiang, Qichen; Yang, Jiaxin

    2014-01-01

    Heat shock proteins (HSPs) are molecular chaperones and have an important role in the refolding and degradation of misfolded proteins, and these functions are related to aging. Rotifer is a useful model organism in aging research, owing to small body size (0.1-1 mm), short lifespan (6-14 days), and senescence phenotypes that can be measured relatively easily. Therefore, we used rotifer as a model to determine the role of four typical hsp genes on the aging process in order to provide a better understanding of rotifer aging. We cloned cDNA encoding hsp genes (hsp40, hsp60, hsp70, and hsp90) from the rotifer Brachionus calyciflorus Pallas, analyzed their molecular characteristics, determined its modulatory response under different temperatures and H2O2 concentrations and investigated the changes in expression of these genes during the aging process. We found that Bchsp70 mRNA expression significantly decreased with aging. In addition, we also studied the effects of dietary restriction (DR) and vitamin E on rotifer lifespan and reproduction and analyzed the changes in expression of these four Bchsp genes in rotifers treated with DR and vitamin E. The results showed that DR extended the lifespan of rotifers and reduced their fecundity, whereas vitamin E had no significant effect on rotifer lifespan or reproduction. Real-time PCR indicated that DR increased the expression of these four Bchsps. However, vitamin E only improved the expression of Bchsp60, and reduced the expression of Bchsp40, Bchsp70, and Bchsp90. DR pretreatment also increased rotifer survival rate under paraquat-induced oxidative stress. These results indicated that hsp genes had an important role in the anti-aging process.

  18. Brachionus plicatilis (Rotifer'in Farklı Besin Ortamlarında Büyümesi.

    Directory of Open Access Journals (Sweden)

    Bircan Özbaş

    2015-12-01

    Full Text Available Farklı besin diyetlerinin rotifer (Brachionus plicatilis kültürlerinin büyümesi üzerindeki etkilerinin araştırıldığı bu çalışmada, rotiferler Nannochloropsis sp., ekmek mayası (Saccharomyces cerevisiae ve kurutulmuş Spirulina tozu ile beslendi. İlk denemede, optimum Spirulina konsantrasyonu günde 0.01 g / 106 rotifer olarak bulundu. Deneme gruplarında alg, alg+maya, alg+Spirulina, maya+Spirulina ve maya/2+Spirulina olmak üzere 5 deneme grubu oluşturuldu. Mikroskobik gözlemlerde, Spirulina partikülleri havanda ezilmiş olmasına rağmen rotiferler tarafından tüketilemeyecek boyutta idi. Sonuç olarak, alg içeren grupların en iyi büyümeyi gösterdiği tespit edildi. Spirulina ise partikül büyüklüğünden dolayı rotiferler tarafından alınamadı. Maya hücreleri ise rotifer hücreleri için optimum büyüklükte olmasına rağmen, ortam kirliliğine neden olması bakımından alg ile beslenen gruplara göre daha düşük bir büyüme gösterdi

  19. The mate recognition protein gene mediates reproductive isolation and speciation in the Brachionus plicatilis cryptic species complex

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    Gribble Kristin E

    2012-08-01

    Full Text Available Abstract Background Chemically mediated prezygotic barriers to reproduction likely play an important role in speciation. In facultatively sexual monogonont rotifers from the Brachionus plicatilis cryptic species complex, mate recognition of females by males is mediated by the Mate Recognition Protein (MRP, a globular glycoprotein on the surface of females, encoded by the mmr-b gene family. In this study, we sequenced mmr-b copies from 27 isolates representing 11 phylotypes of the B. plicatilis species complex, examined the mode of evolution and selection of mmr-b, and determined the relationship between mmr-b genetic distance and mate recognition among isolates. Results Isolates of the B. plicatilis species complex have 1–4 copies of mmr-b, each composed of 2–9 nearly identical tandem repeats. The repeats within a gene copy are generally more similar than are gene copies among phylotypes, suggesting concerted evolution. Compared to housekeeping genes from the same isolates, mmr-b has accumulated only half as many synonymous differences but twice as many non-synonymous differences. Most of the amino acid differences between repeats appear to occur on the outer face of the protein, and these often result in changes in predicted patterns of phosphorylation. However, we found no evidence of positive selection driving these differences. Isolates with the most divergent copies were unable to mate with other isolates and rarely self-crossed. Overall the degree of mate recognition was significantly correlated with the genetic distance of mmr-b. Conclusions Discrimination of compatible mates in the B. plicatilis species complex is determined by proteins encoded by closely related copies of a single gene, mmr-b. While concerted evolution of the tandem repeats in mmr-b may function to maintain identity, it can also lead to the rapid spread of a mutation through all copies in the genome and thus to reproductive isolation. The mmr-b gene is evolving

  20. Demography of zooplankton (Anuraeopsis fissa, Brachionus rubens and Moina macrocopa) fed Chlorella vulgaris and Scenedesmus acutus cultured on different media.

    Science.gov (United States)

    Morales-Ventura, Jesús; Nandini, S; Sarma, S S S; Castellanos-Páez, Maria Elena

    2012-09-01

    Generally zooplankton growth is often limited by the quality of their algal diet. A cheaper common practice in aquaculture, is to culture algae with fertilizers; however, the demography of zooplankton when fed these algae has not yet been evaluated. We studied the population growth and life table demography of the rotifers Anuraeopsis fissa and Brachionus rubens, and the cladoceran Moina macrocopa. For this, the algae Scenedesmus acutus or Chlorella vulgaris were cultured on defined (Bold's basal) medium or the commercial liquid fertilizer (Bayfolan). Experiments were conducted at one algal concentration 1.0 x 10(6) cells/mL of C. vulgaris or its equivalent dry weight of 0.5 x 10(6) cells/mL of S. acutus. The population dynamics were tested at 23 +/- 1 degrees C in 100 mL transparent jars, each with 50mL of the test medium, with an initial density of 0.5indiv/mL, for a total of 48 test jars (3 zooplankton 2 algal species x 2 culture media x 4 replicates). For the life table experiments with M. macrocopa, we introduced 10 neonates (vulgaris cultured in Bold medium. Regardless of the culture medium, Chlorella resulted in significantly higher gross and net reproductive rates for B. rubens than S. acutus diets. The reproductive rates of M. macrocopa were significantly higher in all the tested diets except when fed with S. acutus in Bold medium. The population increase rate, derived from growth experiments of A. fissa and B. rubens, ranged from 0.1-0.25/d and were significantly higher on C vulgaris cultured in liquid fertilizer as compared to the other diets. The growth rates of M. macrocopa ranged from 0.1 to 0.38/d, and were highest with diets of C. vulgaris cultured in Bold medium and S. acutus cultured in fertilizer. Thus, regardless of the culture medium used, the growth rates of the evaluated zooplankton species were higher with Chlorella than with Scenedesmus. The peak population density was highest (2 800ind/mL) for A. fissa fed Chlorella that was cultured on

  1. Demography of zooplankton (Anuraeopsis fissa, Brachionus rubens and Moina macrocopa fed Chlorella vulgaris and Scenedesmus acutus cultured on different media

    Directory of Open Access Journals (Sweden)

    Jesús Morales-Ventura

    2012-09-01

    Full Text Available Generally zooplankton growth is often limited by the quality of their algal diet. A cheaper common practice in aquaculture, is to culture algae with fertilizers; however, the demography of zooplankton when fed these algae has not yet been evaluated. We studied the population growth and life table demography of the rotifers Anuraeopsis fissa and Brachionus rubens, and the cladoceran Moina macrocopa. For this, the algae Scenedesmus acutus or Chlorella vulgaris were cultured on defined (Bold’s basal medium or the commercial liquid fertilizer (Bayfolan. Experiments were conducted at one algal concentration 1.0x10(6cells/mL of C. vulgaris or its equivalent dry weight of 0.5x10(6cells/mL of S. acutus. The population dynamics were tested at 23±1ºC in 100mL transparent jars, each with 50mL of the test medium, with an initial density of 0.5indiv/mL, for a total of 48 test jars (3 zooplankton 2 algal species x 2 culture media x 4 replicates. For the life table experiments with M. macrocopa, we introduced 10 neonates (<24h old into each test jar containing the specific algal type and concentration. For the rotifer experiments, we set 5mL tubes with one neonate each and 10 replicates for each algal species and culture medium. We found that the average rotifer life span was not influenced by the diet, but for M. macrocopa fed S. acutus cultured in Bold’s medium, the average lifespan was significantly lower than with the other diets. The gross and net reproductive rates of A. fissa (ranging from 18-36 offspring per female were significantly higher for C. vulgaris cultured in Bold medium. Regardless of the culture medium, Chlorella resulted in significantly higher gross and net reproductive rates for B. rubens than S. acutus diets. The reproductive rates of M. macrocopa were significantly higher in all the tested diets except when fed with S. acutus in Bold medium. The population increase rate, derived from growth experiments of A. fissa and B. rubens

  2. Life-Span Extension by Caloric Restriction Is Determined by Type and Level of Food Reduction and by Reproductive Mode in Brachionus manjavacas (Rotifera)

    Science.gov (United States)

    2013-01-01

    We measured life span and fecundity of three reproductive modes in a clone of the monogonont rotifer Brachionus manjavacas subjected to chronic caloric restriction (CCR) over a range of food concentrations or to intermittent fasting (IF). IF increased life span 50%–70% for all three modes, whereas CCR increased life span of asexual females derived from sexually or asexually produced eggs, but not that of sexual females. The main effect of CR on both asexual modes was to delay death at young ages, rather than to prevent death at middle ages or to greatly extend maximum life span; in contrast CR in sexual females greatly increased the life span of a few long-lived individuals. Lifetime fecundity did not decrease with CCR, suggesting a lack of resource allocation trade-off between somatic maintenance and reproduction. Multiple outcomes for a clonal lineage indicate that different responses are established through epigenetic programming, whereas differences in life-span allocations suggest that multiple genetic mechanisms mediate life-span extension. PMID:22904096

  3. Life strategy and grazing intensity responses of Brachionus calyciflorus fed on different concentrations of microcystin-producing and microcystin-free Microcystis aeruginosa

    Science.gov (United States)

    Liang, Ye; Ouyang, Kai; Chen, Xinglan; Su, Yuqi; Yang, Jiaxin

    2017-02-01

    The occurrence of Microcystis blooms is a worldwide concern due to the numerous adverse effects on zooplankton. We therefore hypothesized that the cyanobacterium Microcystis aeruginosa is harmful to rotifer growth. Population and individual experiments were conducted with the same proportional volumes of Chlorella and Microcystis for given food densities. Life-table parameters, life-history traits, and the grazing intensity of Brachionus calyciflorus were evaluated after they had fed on microcystin-producing and microcystin-free Microcystis, both alone and combined with an edible alga (Chlorella pyrenoidosa), at concentrations of 1 × 105, 1 × 106, and 1 × 107 cells mL-1. The results showed that the interactive effects of food density and type appeared to be synergistic on generation time (T), net reproduction rate (R0), body length, swimming speed, and reproduction time. In contrast, these effects appeared to be antagonistic on intrinsic growth rate (r), finite rate of increase (λ), time to first brood, post-reproductive time and total offspring per female. The grazing rate of rotifers decreased with grazing time. Although the toxins released after grazing on M. aeruginosa had negative effects on rotifer growth and reproduction, B. calyciflorus changed its life strategy and grazing intensity in response to eutrophic conditions.

  4. Triclosan (TCS) and Triclocarban (TCC) cause lifespan reduction and reproductive impairment through oxidative stress-mediated expression of the defensome in the monogonont rotifer (Brachionus koreanus).

    Science.gov (United States)

    Han, Jeonghoon; Won, Eun-Ji; Hwang, Un-Ki; Kim, Il-Chan; Yim, Joung Han; Lee, Jae-Seong

    2016-01-01

    Triclosan (TCS) and Triclocarban (TCC) are used as antimicrobial agents and have been widely dispersed and detected in the marine environment. However, the toxicities of TCS and TCC have been poorly investigated in marine invertebrates. In this study, the effects of TCS and TCC on mortality, population growth, lifespan, and fecundity were examined in the monogonont rotifer (Brachionus koreanus) using cellular ROS levels, GST enzymatic activity, and gene expression of defensomes. The median lethal concentration (LC50) of TCS (393.1μg/L) and TCC (388.1μg/L) was also determined in the same species. In TCS- and TCC-exposed B. koreanus, growth retardation and reduced fecundity were observed and were shown to have a potentially deleterious effect on the life cycle of B. koreanus. In addition, time-dependent increases in ROS content (%) and GST enzymatic activity were shown in response to TCS and TCC exposure. Additionally, transcript levels of detoxification proteins (e.g., CYPs), antioxidant proteins (e.g., GST-sigma, Cu/ZnSOD, CAT), and heat shock proteins (Hsps) were modulated in response to TCS and TCC exposure over a 24h period. Our results indicate that TCS and TCC induce oxidative stress and transcriptional regulation of detoxification, antioxidant, and heat shock proteins, resulting in changes in lifespan and fecundity. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Immunodetection of Luteinizing Hormone (LH, Follicle-Stimulating Hormone (FSH, Thyroid Stimulating Hormone (TSH and Prolactin (PRL in Brachionus calyciflorus (Rotifera: Monogononta

    Directory of Open Access Journals (Sweden)

    Jesús Alvarado-Flores

    2009-12-01

    Full Text Available The endocrine system controls and coordinates behavioral, biochemical, and physiological processes through signal mechanisms using neuropeptides or products of neurosecretory cells. Among invertebrates, this system is poorly studied in rotifers, in which estrogens and androgens significantly affect sexual reproduction. This is the first report of the presence of the Luteinizing Hormone (LH, Follicle-Stimulating Hormone (FSH, Thyroid Stimulating Hormone (TSH and Prolactin (PRL in rotifers. Analyses included the avidin-biotin-peroxidase complex method with primary antibodies LH (Anti-Rat LH serum for RIA, PRL (Anti-Rat PRL serum for RIA, FSH (Anti-Rat FSH serum for RIA and TSH (Anti-Rat TSH serum for RIA. These hormones were found in females, males and parthenogenetic and sexual eggs of the freshwater Brachionus calyciflorus. The immunoreactivity of FSH, LH, TSH and PRL in females was observed in: ovaries, cerebrum, mastax, stomach, lorica, and the stomach gland. However, in males LH was observed only at the trochal disk and cerebrum. The hormones FSH, TSH and PRL, were observed in testicles, contractil vesicles, and cementary gland of males. Regarding amictic or parthenogenetic eggs, the hormones LH, FSH, TSH, and PRL were located mainly in the micromeres, and the staining in the macromeres was weak. On the other hand, in the mictic or sexual eggs the inner shell is stained for the hormones PRL and LH, opposite to the staining of FSH and TSH, located mainly in the embryo. In general, immuno-reactivity was observed in areas important for the reproductive, excretory, digestive and developmental processes. Rev. Biol. Trop. 57 (4: 1049-1058. Epub 2009 December 01.Se logró detectar la presencia de las hormonas: Hormona Luteinizante (LH, Hormona Folículo Estimulante (FSH, Hormona Estimulante de la Tiroides (TSH y Prolactina (PRL en Brachionus calyciflorus siendo el primer reporte de la presencia de dichas hormonas en rotíferos. Estas hormonas fueron

  6. Dinámica poblacional del rotífero Brachionus ibericus aislado de estanques para camarón, alimentado con diferentes dietas

    Directory of Open Access Journals (Sweden)

    José Cristóbal Román-Reyes

    2014-11-01

    Full Text Available La producción de microalgas vivas para cultivar rotíferos constituye uno de los mayores costos de operación en la larvicultura de peces, por lo que se están desarrollando sustitutos comerciales de microalgas para la alimentación y producción de rotíferos. Se desconoce el efecto que tienen las formulaciones comerciales sobre la dinámica poblacional de rotíferos nativos del noroeste de México y en este estudio se evaluó el efecto de cuatro dietas comerciales (Espirulina, RotiMac®, Nanno 3600®, RotiGrow-Plus® y la microalga viva Nannochloropsis sp., sobre el crecimiento poblacional y fecundidad del rotífero Brachionus ibericus (GenBank KJ949043, aislado de una granja de camarón blanco (Litopenaeus vannamei. Se realizaron cinco réplicas por tratamiento alimenticio utilizando recipientes con volumen de 12 L de agua, con temperatura de 29 ± 1°C y salinidad de 35 ± 1, respectivamente. Los resultados mostraron que durante los periodos experimentales, las dietas probadas resultaron adecuadas para alimentar a B. ibericus, con tasas de crecimiento, tiempos de duplicación, densidades máximas y fecundidades que fluctuaron entre 0.20 a 0.27 rotíferos día-1, 2.60 a 3.42 días, 215 a 344 rotíferos mL-1 y de 0.16 a 0.39 huevos hembra-1, respectivamente. Las diferencias entre tratamientos fueron significativas (P 0.05 a las obtenidas con Nanno 3600®.

  7. Use of Probiotic Bacillus spp. in Rotifer (Brachionus plicatilis) and Artemia (Artemia urmiana) Enrichment: Effects on Growth and Survival of Pacific White Shrimp, Litopenaeus vannamei, Larvae.

    Science.gov (United States)

    Jamali, Hadi; Imani, Ahmad; Abdollahi, Daruosh; Roozbehfar, Reza; Isari, Amin

    2015-06-01

    This study was to evaluate the effect of a preparation of Bacillus probiotic (Bacillus licheniformis and B. subtilis, 1:1) on growth and survival rate of Pacific white shrimp, Litopenaeus vannamei larvae. The larvae were fed on Artemia urmiana nauplii and Brachionus plicatilis enriched with the probiotic preparation at 1 × 10(6) CFU mL(-1) rate. The experimental setup was completely randomized design comprised of six treatments, namely solo Artemia nauplii (A) or rotifer (R), Artemia nauplii and rotifer without any enrichment (A + R), Artemia nauplii enrichment with probiotic bacilli (Bacillus licheniformis and B. subtilis) (A + B), rotifer enrichment with probiotic bacilli (R + B) and enriched Artemia nauplii and rotifer (A + R + B). All treatments were performed in triplicate. Chemical parameters of rearing water viz. pH, salinity and temperature were 7.5-8, 30-31 ppt and 31-32 °C, respectively. Photoperiod was 16L:8D. Shrimp larvae were fed Artemia nauplii and rotifers at 5-20 and 10-40 individuals per shrimp larvae four times a day, respectively. Growth and survival rate of larvae were determined at MII, MIII, PL1, PL4, PL7 and PL10 stages. Larvae in A + R + B treatment showed the highest total length (10.89 ± 0.51 mm), weight (674 ± 73 μg) and survival rate (65% ± 3.5). Lowest total length, weight and survival rate (7.96 ± 0.63 mm, 493 ± 52 μg and 24.5 ± 2.4%, respectively) were recorded in treatment B larvae. We concluded that Bacillus probiotic can improve growth and survival rate of Pacific white shrimp larvae without conceivably undesirable effects.

  8. Experimental evidence of the effect of nutrient enrichment on the zooplankton in a Brazilian coastal lagoon

    Directory of Open Access Journals (Sweden)

    B. KOZLOWSKY-SUZUKI

    Full Text Available Non-treated sewage disposal is one of the main impacts to which Imboassica Lagoon has been subjected. The aim of this study was to evaluate the effect of a potential increase in the artificial enrichment on the environmental conditions and zooplankton of this system. To this end, an experimental study was conducted in mesocosms where nutrients were added daily. Bacterial numbers, chlorophyll-a, and picoplanktonic cyanobacteria densities showed an increase with the availability of nutrients. Bacterio- and phytoplankton seemed to be regulated by the rotifers Brachionus rotundiformis and Hexarthra brandorffi.

  9. Performances zootechniques comparées de Rotifères d'eau douce Brachionus calyciflorus et de nauplii d'Artemia salina chez les larves de la perche fluviatile Perca fluviatilis

    Directory of Open Access Journals (Sweden)

    Fiogbé, ED.

    2003-01-01

    Full Text Available Zootechnic Performences Compared between Freshwater Rotifer (Brachionus calyciflorus and Nauplii Artemia salina in River Perch Perca fluviatilis L. In able to improve survival rate and growth in perch Perca fluviatilis larvae which are very small at hatching stage, larvae are submitted two days after hatching to different live food: fresh water Rotifer Brachionus calyciflorus and nauplii of Artemia salina.Thus, to avoid the big mortality which occure because of manipulation of larvae, eggs in eye stage were shared in two duplicated groups and feeding of larvae started two days after hatching. Mortality was significant in the two groups from the day 7. However, at the end of the experiment, the group fed Rotifer at the begining of feeding, exhibited the best homogeneity, the best survival and the best food convertion ratio. So, this experiment has shown clearly that at hatching time, all perch larvae are not able to ingest nauplii Artemia. It is necessary to mix their starter food with Rotifer.

  10. Intracellular haemolytic agents of Heterocapsa circularisquama exhibit toxic effects on H. circularisquama cells themselves and suppress both cell-mediated haemolytic activity and toxicity to rotifers (Brachionus plicatilis).

    Science.gov (United States)

    Nishiguchi, Tomoki; Cho, Kichul; Yasutomi, Masumi; Ueno, Mikinori; Yamaguchi, Kenichi; Basti, Leila; Yamasaki, Yasuhiro; Takeshita, Satoshi; Kim, Daekyung; Oda, Tatsuya

    2016-10-01

    A harmful dinoflagellate, Heterocapsa circularisquama, is highly toxic to shellfish and the zooplankton rotifer Brachionus plicatilis. A previous study found that H. circularisquama has both light-dependent and -independent haemolytic agents, which might be responsible for its toxicity. Detailed analysis of the haemolytic activity of H. circularisquama suggested that light-independent haemolytic activity was mediated mainly through intact cells, whereas light-dependent haemolytic activity was mediated by intracellular agents which can be discharged from ruptured cells. Because H. circularisquama showed similar toxicity to rotifers regardless of the light conditions, and because ultrasonic ruptured H. circularisquama cells showed no significant toxicity to rotifers, it was suggested that live cell-mediated light-independent haemolytic activity is a major factor responsible for the observed toxicity to rotifers. Interestingly, the ultrasonic-ruptured cells of H. circularisquama suppressed their own lethal effect on the rotifers. Analysis of samples of the cell contents (supernatant) and cell fragments (precipitate) prepared from the ruptured H. circularisquama cells indicated that the cell contents contain inhibitors for the light-independent cell-mediated haemolytic activity, toxins affecting H. circularisquama cells themselves, as well as light-dependent haemolytic agents. Ethanol extract prepared from H. circularisquama, which is supposed to contain a porphyrin derivative that displays photosensitising haemolytic activity, showed potent toxicity to Chattonella marina, Chattonella antiqua, and Karenia mikimotoi, as well as to H. circularisquama at the concentration range at which no significant toxicity to rotifers was observed. Analysis on a column of Sephadex LH-20 revealed that light-dependent haemolytic activity and inhibitory activity on cell-mediated light-independent haemolytic activity existed in two separate fractions (f-2 and f-3), suggesting that both

  11. Reproductive behavior, embryonic and early larval development of the red head goby, Elacatinus puncticulatus.

    Science.gov (United States)

    Pedrazzani, Ana Silvia; Pham, Nancy Kim; Lin, Junda; Neto, Antonio Ostrensky

    2014-02-01

    The goals of this study are to provide a technical foundation for the production of the red head goby Elacatinus puncticulatus by evaluating its reproductive behavior and its embryonic and early larval development. Five pairs were kept under controlled conditions for thirty days. Courtship behavior, spawning period and the number of eggs produced were recorded. For the evaluation of embryo development, eggs were sampled at 12, 18, 24, 48, 72, 96, 120, 144 and 168h post-fertilization(HPF). To test the influence of the incubation period on larval total length and height, eggs with six days (6D) of incubation and with seven days of incubation (7D) were subjected to flashlight illumination for 30min to induce larval hatching. Another experiment evaluated the difference in larval survival with three different diets: Euplotes sp. (EU); rotifers Brachionus rotundiformis and Brachionus plicatilis and Paramecium sp. (BP); plankton collected from the wild (WP). The males displayed a gray head and pale yellow and black body coloration. Females exhibited strong red and black colors until three days before spawning, which occurred at intervals of 7 to 10 days. The hatching rate was 98-99%. The larvae total mean lengths and heights were 3.05 and 2.95mm (p>0.05) and 0.37 and 0.48mm (p<0.05) for treatments 6D and 7D, respectively. However, both groups exhibited high mortality at 5 days post-hatch (DPH). No larvae from the EU group survived after 5 DPH. At 8 DPH, 4% survivorship was found in treatment BP and 2% in treatment WP. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. EFISIENSI PRODUKSI PAKAN ALAMI SECARA INTENSIF

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    Gede S. Sumiarsa

    2011-12-01

    Full Text Available Rotifer Brachionus rotundiformis merupakan pakan alami utama yang dipergunakan dalam perbenihan ikan-ikan laut. Produksi rotifer pada percobaan ini dilakukan dalam wadah kecil (0,5 m3 dengan padat penebaran awal 100-150 ekor/mL, diberikan fitoplankton Nannochloropsis oculata kepadatan tinggi (1,0-2,0x108 sel/mL didalam dan di luar ruangan.  Oksigen murni dialirkan ke dalam bak-bak budidaya rotifer dengan laju 0,05-0,1 L/menit sedangkan penghitungan kepadatan fitoplankton, rotifer, dan pemeriksaan kualitas air dilakukan setiap hari. Rata-rata kepadatan akhir rotifer budidaya didalam ruangan pada hari hari ke 7-9 adalah 525±6,1 ekor/mL sedangkan budidaya rotifer di luar ruangan hanya mampu berlangsung selama 2-4 hari dengan kepadatan yang terus menurun setelah penebaran awal. Kandungan lemak rotifer adalah 14,0%, dengan kandungan asam lemak DHA: 1,4 mg/g DW, EPA 57,2 mg/g DW, dan HUFA: 61,5 mg/g DW dengan rasio DHA/EPA 0,02. Suhu air, pH, dan total amonium berturut-turut berkisar pada nilai 26,1oC-34,1oC, 8,3-8,8 dan 0,48-2,20 mg/L.

  13. Effect of enriched Brachionus plicatilis and Artemia salina nauplii by ...

    African Journals Online (AJOL)

    The total fatty acids in T. chuii especially the polyunsaturated fatty acid were represented by content 5.5% [arachidonic acid (ARA)], 4.8% [eicosapentaenoic acid (EPA)] and 5.0% [docosahexaenoic acid (DHA)] to the total fatty acids. The higher production of total fatty acids in B. plicatilis fed on T. chuii grown in Erdschriber ...

  14. Preliminary Study on Hatching of Rotifers (Brachionus plicatilis) and ...

    African Journals Online (AJOL)

    ponds flooded and fertilised with chicken manure yielded significantly more rotifers (26 ± 1 / ml), compared to a maximum of only 8 ± 0.5 rotifers/ml counted in the control unfertilised pond. These results suggest that it is possible to induce hatching and production of rotifers by manipulating salinity and fertility of ponds.

  15. Genetic determinants of mate recognition in Brachionus manjavacas (Rotifera)

    OpenAIRE

    Kubanek Julia; Smith Hilary A; Shearer Tonya L; Snell Terry W; Gribble Kristin E; Welch David

    2009-01-01

    Abstract Background Mate choice is of central importance to most animals, influencing population structure, speciation, and ultimately the survival of a species. Mating behavior of male brachionid rotifers is triggered by the product of a chemosensory gene, a glycoprotein on the body surface of females called the mate recognition pheromone. The mate recognition pheromone has been biochemically characterized, but little was known about the gene(s). We describe the isolation and characterizatio...

  16. Preliminary Study on Hatching of Rotifers ( Brachionus plicatilis ...

    African Journals Online (AJOL)

    Key words: rotifers, copepods, mesocosm, hatching, flooding and fertilisation. The effect of water flooding, organic fertiliser application and salinity manipulation in stimulating the hatching of rotifer resting eggs was investigated during the dry season (in August/September 1999) in simulation tanks and earthen ponds at ...

  17. Combined effects of temperature and lead concentration on the competition between the rotifers Brachionus havanaensis and Brachionus rubens (Rotifera: Brachionidae).

    Science.gov (United States)

    Montúfar-Meléndez, Aramen Iván; Sánchez-Ortíz, Jonathan Raúl; Sarma, S S S; Nandini, S

    2007-02-15

    The combined effects of temperature (22 and 32 degrees C) and the concentration of Pb (0, 0.05, 0.1 and 0.2 mg L- 1) on the competition between B. havanaensis and B. rubens using population growth was evaluated. At 22 degrees C, increase in Pb concentration had little effect on the population growth of B. havanaensis, while it had adverse effect on B. rubens. At this temperature, the presence of B. rubens had adversely affected the growth of B. havananensis. However, under similar conditions, B. rubens was not influenced by B. havanaensis. Increase in Pb concentration decreased the population growth of B. havanaensis at 32 degrees C regardless whether the population was alone or together with B. rubens. When grown alone, B. havanaensis was numerically more abundant than B. rubens. B. havanaensis grown at 32 degrees C had population growth rates of 0.32 to 0.56 day- 1, depending on Pb level and the presence of competitor. At this temperature, B. rubens had mostly negative growth rates. Further, our study showed that Pb at a concentration as low as 0.05 mg L- 1 had adverse effect on B. rubens at both the temperatures. Though B. rubens is known to occur naturally at wide temperature range, in our study this species appeared to have adapted to low temperature.

  18. Effect of three food types on the population growth of Brachionus calyciflorus and Brachionus patulus (Rotifera: Brachionidae

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    S.S.S. Sarma

    2001-03-01

    Full Text Available We compared the population growth of B. calyciflorus and B. patulus using the green alga Chlorella vulgaris, baker’s yeast Saccharomyces cerevisiae or their mixture in equal proportions as food. Food was offered once every 24 h in two concentrations (low: 1x10(6 and high: 3x10(6 ind. ml-1 separately for each species. The experiments were terminated after 15 days. In general, at any food type or concentration, B. patulus reached a higher population density. A diet of Chlorella alone supported a higher population growth of both rotifer species than yeast alone. B. calyciflorus and B. patulus achieved highest population densities (103+8 ind. ml-1 and 296+20 ind. ml-1, respectively on a diet of Chlorella at 3x10(6 ind. ml-1. When cultured using the mixture of Chlorella and yeast, the maximal population densities of B. calyciflorus were lower than those grown on Chlorella. Under similar conditions, the maximal abundance values of B. patulus were comparable in both food types. Regardless of food type and density the rate of population increase per day (r for B. calyciflorus varied from 0.13+0.03 to 0.63+0.04. These values for B. patulus ranged from 0.19+0.01 to 0.37+0.01. The results indicated that even though Chlorella was a superior foof for the tested rotifers, yeast can be effectively used at low concentrations to supplement algal requirements in rotifer culture systems.Se comparó el crecimiento poblacional de dos especies planctónicas (B. calyciflorus y B. patulus desarrolladas con el alga verde Chlorella vulgaris, la levadura de cerveza Saccharomyces cerevisiae y la mezcla de ambas dietas en proporciones iguales. B. patulus alcanzó las mayores densidades con cualquier tipo de alimento utilizado en comparación con B. calyciflorus. La dieta a base de Chlorella vulgaris sola promovió el mayor crecimiento poblacional en relación con la dieta de levadura sola. B. calyciflorus y B. patulus alcanzaron las mayores densidades de 103+8 ind. ml-1 y 296+20 ind. ml-1, respectivamente, con la dieta de Chlorella en 3x10(6 células ml-1. En condiciones similares, los valores máximos de abundancia de B. patulus fueron semejantes para ambos tipos de alimento. La tasa de incremento poblacional por día (r para B. calyciflorus vario de 0.13+0.03 a 0.63+0.04, sin importar el tipo y densidad de alimento. Los resultados indican que la dieta a base de Chlorella fue mejor para los rotíferos considerados, y que la levadura puede usarse de manera efectiva a concentraciones bajas para complementar los requerimientos algales del sistema de cultivo de rotíferos.

  19. Effect of dietary (n-3 highly unsaturated fatty acids on growth and survival of fat snook (Centropomus parallelus, Pisces: Centropomidae larvae during first feeding

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    Seiffert M.E.B.

    2001-01-01

    Full Text Available The effect of rotifers, Brachionus rotundiformis (S-type, fed three different diets: A (rotifer fed Nannochloropsis oculata, B (rotifer fed N. oculata and baker's yeast, 1:1, and C (rotifer fed N. oculata and baker's yeast, 1:1, and enriched with Selcoâ, was evaluated based on the survival, growth and swim bladder inflation rate of fat snook larvae. Rotifers of treatment A had higher levels (4.58 mg/g dry weight of eicosapentaenoic acid (EPA than B (1.81 mg/g dry weight, and similar levels (0.04 and 0.06 mg/g dry weight, respectively of docosahexaenoic acid (DHA. Rotifers of treatment C had the highest levels of EPA (13.2 mg/g dry weight and DHA (6.08 mg/g dry weight. Fat snook eggs were obtained by spawning induction with human chorionic gonadotropin. Thirty hours after hatching, 30 larvae/liter were stocked in black cylindric-conical tanks (36-liter capacity. After 14 days of culture, there were no significant differences among treatments. Mean standard length was 3.13 mm for treatment A, 3.17 mm for B, and 3.39 mm for C. Mean survival rates were very low (2.7% for treatment A, 2.3% for B, and 1.8% for C. Swim bladder inflation rates were 34.7% for treatment A, 27.1% for B, and 11.9% for C. The lack of differences in growth and survival among treatments showed that the improvement of the dietary value of rotifer may not have been sufficient to solve the problem of larval rearing. Some other factor, probably pertaining to the quality of the larvae, may have negatively influenced survival.

  20. Combined effect of concentrations of algal food (Chlorella vulgaris and salt (sodium chloride on the population growth of Brachionus calyciflorus and Brachionus patulus (Rotifera

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    Víctor M. Peredo-Álvarez

    2003-06-01

    Full Text Available Salinity is an important variable influencing the density and diversity of rotifers. Studies on salt tolerance of rotifers have so far concentrated on euryhaline species while very little information is available on noneuryhaline taxa. In the present work, we have evaluated the combined effects of Chlorella vulgaris and sodium chloride on the population growth of two freshwater rotifers B. calyciflorus and B. patulus. A 24 hr acute tolerance test using NaCl revealed that B. calyciflorus was more resistant (LC50 = 3.75 ± 0.04 g l-1 than B. patulus (2.14 ± 0.09 g l-1 . The maximal population density (mean±standard error for B. calyciflorus in the control at 4.5 X10 6 cells ml-1 (algal level was 80 ±5 ind. ml-1 , which was nearly a fifth of the one for B. patulus (397 ± 7 ind. ml-1 under comparable conditions. Data on population growth revealed that regardless of salt concentration, the density of B. calyciflorus increased with increasing food levels, while for B. patulus, this trend was evident only in the controls. Regardless of salt concentration and algal food level, the day of maximal population density was lower (4 ± 0.5 days for B. calyciflorus than for B. patulus (11 ±1 day. The highest rates of population increase (r values for B. calyciflorus and B. patulus were 0.429 ± 0.012 and 0.367 ± 0.004, respectively, recorded at 4.5 X10(6 cells ml-1 of Chlorella in the controls. The protective role of algae in reducing the effect of salt stress was more evident in B. calyciflorus than B. patulus.La salinidad es una variable importante que tiene influencia sobre la densidad y la diversidad de los rotíferos. Los estudios de rotíferos sobre tolerancia a la sal que se tienen hasta ahora se han concentrado en especies eurihalinas, sin embargo, hay muy poca información sobre taxas no eurihalinos. En el presente trabajo, se evaluaron los efectos combinados de las concentraciones de Chlorella vulgaris y cloruro de sodio sobre el crecimiento poblacional de dos rotíferos de agua dulce, B. calyciflorus y B. patulus. Una prueba de toxicidad aguda de 24 h utilizando cloruro de sodio reveló que B. calyciflorus fue más resistente (CL50 = 3.75 ± 0.04 g l -1 que B. patulus (2.14 ± 0.09 g l-1 . La máxima densidad de población (media ± error estándar de B. calyciflorus en el lote control, utilizando una concentración 4.5 X10(6 células ml-1 de alga fue de 80 ± 5 ind. ml-1 , casi una quinta parte de B. patulus (397 ±7 ind. ml-1 sobre condiciones comparables. Datos sobre el crecimiento poblacional revelaron que cualquier concentración de sal carece de efecto, la densidad de B. calyciflorus se incrementa cuando aumentan los niveles de alimento. Sin embargo para B. patulus esta tendencia fue evidente únicamente en los controles. Independientemente de las concentraciones de sal y los niveles de alimento, el día de abundancia máxima fue menor para B. calyciflorus (4 ± 0.5 días que para B. patulus (11 ±1 días. Los valores de la máxima tasa de crecimiento poblacional (r fueron para B. calyciflorus y B. patulus de 0.429 ± 0.012 y 0.367 ± 0.004, respectivamente en lotes control con 4.5 X10(6 células ml-1 de Chlorella. El papel de protección de alga para reducir el efecto del estrés de la sal fue más evidente en B. calyciflorus que en B. patulus.

  1. Effects of food quality on life history of the rotifer Brachionus calyciflorus Pallas

    NARCIS (Netherlands)

    Jensen, T.C.; Verschoor, A.M.

    2004-01-01

    1. Herbivorous zooplankton face considerable temporal and spatial variation in food quality, to which they respond by adapting their life histories. Zooplankton may even take up mineral nutrients directly, and use these to counter the effects of algal nutrient limitation (mineral compensation). This

  2. Effect of Brachionus rubens on the growth characteristics of various species of microalgae

    Directory of Open Access Journals (Sweden)

    Reda A.I. Abou-Shanab

    2016-07-01

    Conclusions: Variations in susceptibility of algal species to rotifer predation could be a result of their individual morphology, cell walls structure, or the biochemical composition of individual species.

  3. Stress granules form in Brachionus manjavacas (Rotifera) in response to a variety of stressors.

    Science.gov (United States)

    Jones, Brande L; VanLoozen, Josephine; Kim, Min H; Miles, Stacey J; Dunham, Christine M; Williams, Loren Dean; Snell, Terry W

    2013-10-01

    Many eukaryotes share a common response to environmental stresses. The responses include reorganization of cellular organelles and proteins. Similar stress responses between divergent species suggest that these protective mechanisms may have evolved early and been retained from the earliest eukaryotic ancestors. Many eukaryotic cells have the capacity to sequester proteins and mRNAs into transient stress granules (SGs) that protect most cellular mRNAs (Anderson and Kedersha, 2008). Our observations extend the phylogenetic range of SGs from trypanosomatids, insects, yeast and mammalian cells, where they were first described, to a species of the lophotrochozoan animal phylum Rotifera. We focus on the distribution of three proteins known to be associated with both ribosomes and SG formation: eukaryotic initiation factors eIF3B, eIF4E and T-cell-restricted intracellular antigen 1. We found that these three proteins co-localize to SGs in rotifers in response to temperature stress, osmotic stress and nutrient deprivation as has been described in other eukaryotes. We have also found that the large ribosomal subunit fails to localize to the SGs in rotifers. Furthermore, the SGs in rotifers disperse once the environmental stress is removed as demonstrated in yeast and mammalian cells. These results are consistent with SG formation in trypanosomatids, insects, yeast and mammalian cells, further supporting the presence of this protective mechanism early in the evolution of eukaryotes. © 2013.

  4. Eco-physiology, mass production and larvaebreeding potentialities of the fresh water rotifer Brachionus calyciflorus Pallas

    Directory of Open Access Journals (Sweden)

    Awaïss, A.

    1991-01-01

    Full Text Available In veterinary medicine of african tradition in Kivu and Kibali-lturi (Zaire, we have identified 32 medicinal plants used alone or in association at the time of verminosis, diarrhea, coprostasis and meteorism. The parts of the plant intervene in the following proportions : leaves (59 %, fruits and seeds (12 %, whole plant (12 %, stems barks (9 %, roots, rhizoms and tubers (5 %, roots'barks (3 %. After maceration (51 % of cases, decoction (25 % or without modification (20 %, the way of administration is oral in 90 % of cases and anal in 10 % of cases. Our data led us to suggest that plants previously submitted to a pharmacological screening could be introduced and maintained by management technics of paturages before pharmacotechnical studies or industrial production of medicaments.

  5. Antioxidants can extend lifespan of Brachionus manjavacas (Rotifera), but only in a few combinations

    Science.gov (United States)

    Fields, Allison M.; Johnston, Rachel K.

    2013-01-01

    Animal cells are protected from oxidative damage by an antioxidant network operating as a coordinated system, with strong synergistic interactions. Lifespan studies with whole animals are expensive and laborious, so there has been little investigation of which antioxidant interactions might be useful for life extension. Animals in the phylum Rotifera are particularly promising models for aging studies because they are small (0.1–1 mm), have short, two-week lifespan, display typical patterns of animal aging, and have well characterized, easy to measure phenotypes of aging and senescence. One class of interventions that has consistently produced significant rotifer life extension is antioxidants. Although the mechanism of antioxidant effects on animal aging remains controversial, the ability of some antioxidant supplements to extend rotifer lifespan was unequivocal. We found that exposing rotifers to certain combinations of antioxidant supplements can produce up to about 20% longer lifespan, but that most antioxidants have no effect. We performed life table tests with 20 single antioxidants and none yielded significant rotifer life extension. We tested 60 two-way combinations of selected antioxidants and only seven (12%) produced significant rotifer life extension. None of the 20 three- and four-way antioxidant combinations tested yielded significant rotifer life extension. These observations suggest that dietary exposure of antioxidants can extend rotifer lifespan, but most antioxidants do not. We observed significant rotifer life extension only when antioxidants were paired with trolox, N-acetyl cysteine, l-carnosine, or EUK-8. This illustrates that antioxidant treatments capable of rotifer life extension are patchily distributed in the parameter space, so large regions must be searched to find them. It furthermore underscores the value of the rotifer model to conduct rapid, facile life table experiments with many treatments, which makes such a search feasible. Although some antioxidants extended rotifer lifespan, they likely did so by another mechanism than direct antioxidation. PMID:22270335

  6. The mate recognition protein gene mediates reproductive isolation and speciation in the Brachionus plicatilis cryptic species complex

    National Research Council Canada - National Science Library

    Gribble, Kristin E; Mark Welch, David B

    2012-01-01

    .... plicatilis species complex, examined the mode of evolution and selection of mmr-b, and determined the relationship between mmr-b genetic distance and mate recognition among isolates. Isolates of the B...

  7. Investigation of a rotifer (Brachionus calyciflorus) - green alga (Scenedesmus pectinatus) interaction under non- and nutrient-limited conditions

    NARCIS (Netherlands)

    Lürling, M.F.L.L.W.

    2006-01-01

    Two-day life cycle tests with the rotifer Brachiomus calyciflorus were run to study the nutritional quality effects to rotifers of Scenedesmus pectinatus grown under non-limiting nitrogen limiting and phosphorus limiting conditions and the feedback of the rotifers oil the Food algae. Under

  8. Use of flubendazole as a therapeutic agent against rotifers (Brachionus plicatilis) in intensive cultures of the harpacticoid copepod Tisbe holothuriae

    DEFF Research Database (Denmark)

    Steenfeldt, Svend Jørgen; Nielsen, Johan W.

    2010-01-01

    Copepods are well known to be the optimal live feed for most species of marine fish larvae. Still copepods are rarely used in marine hatcheries worldwide. Lack of efficient production techniques are among the reasons for this. Consequently, Artemia and rotifers are utilized in commercial settings...

  9. Changes in expression of manganese superoxide dismutase, copper and zinc superoxide dismutase and catalase in Brachionus calyciflorus during the aging process.

    Science.gov (United States)

    Yang, Jianghua; Dong, Siming; Jiang, Qichen; Kuang, Tengjiao; Huang, Wenting; Yang, Jiaxin

    2013-01-01

    Rotifers are useful model organisms for aging research, owing to their small body size (0.1-1 mm), short lifespan (6-14 days) and the relative easy in which aging and senescence phenotypes can be measured. Recent studies have shown that antioxidants can extend the lifespan of rotifers. In this paper, we analyzed changes in the mRNA expression level of genes encoding the antioxidants manganese superoxide dismutase (MnSOD), copper and zinc SOD (CuZnSOD) and catalase (CAT) during rotifer aging to clarify the function of these enzymes in this process. We also investigated the effects of common life-prolonging methods [dietary restriction (DR) and resveratrol] on the mRNA expression level of these genes. The results showed that the mRNA expression level of MnSOD decreased with aging, whereas that of CuZnSOD increased. The mRNA expression of CAT did not change significantly. This suggests that the ability to eliminate reactive oxygen species (ROS) in the mitochondria reduces with aging, thus aggravating the damaging effect of ROS on the mitochondria. DR significantly increased the mRNA expression level of MnSOD, CuZnSOD and CAT, which might explain why DR is able to extend rotifer lifespan. Although resveratrol also increased the mRNA expression level of MnSOD, it had significant inhibitory effects on the mRNA expression of CuZnSOD and CAT. In short, mRNA expression levels of CAT, MnSOD and CuZnSOD are likely to reflect the ability of mitochondria to eliminate ROS and delay the aging process.

  10. Effect of temperature and viscosity on swimming velocity of the copepod Acartia tonsa, brine shrimp Artemia salina and rotifer Brachionus plicatilis

    DEFF Research Database (Denmark)

    Larsen, Poul Scheel; Madsen, C.V.; Riisgard, H.U.

    2008-01-01

    that the temperature-dependent viscosity of seawater is the key physical/mechanical factor that controls the beat frequency of water-pumping cilia in mussels and the swimming velocity in a ciliate. The present study on the swimming velocity of 3 zooplankton organisms, however, shows that the response of swimming...... velocity to a change in viscosity is different when due to a change in temperature or, at constant temperature, due to a manipulation of viscosity by addition of a high-molecular-weight polymer (polyvinyl pyrrolidone, PVP) to the ambient seawater. There is a biological effect (fraction of total reduction......) due to change in kinematic viscosity (v) be correlated in terms of a power law, V proportional to v(-m). The present data on swimming velocity of copepods, brine shrimps and rotifers show values of exponent m approximate to 1.5 to 3, with a trend of decreasing values for increasing size of species...

  11. Responses of the rotifer Brachionus calyciflorus to two tropical toxic cyanobacteria (Cylindrospermopsis raciborskii and Microcystis aeruginosa) in pure and mixed diets with green algae

    NARCIS (Netherlands)

    Soares, M.C.S.; Lürling, M.F.L.L.W.; Huszar, V.M.

    2010-01-01

    Cyanobacteria are known for being inadequate as a food source for zooplankton, whether by their toxicity, large size, lack of essential compounds or due to feeding inhibitors. In eutrophic systems, however, higher abundance of rotifers is often observed with higher abundance of cyanobacteria, which

  12. Global isolation by distance despite strong regional phylogeography in a small metazoan

    National Research Council Canada - National Science Library

    Mills, Scott; Lunt, David H; Gómez, Africa

    2007-01-01

    ... observed in larger taxa. Here we investigate the patterns of genetic diversity, amongst populations of the salt lake microscopic metazoan Brachionus plicatilis s. s. (sensu stricto) (Rotifera: Monogononta) on a global scale...

  13. Rotifers ingest oocysts of Cryptosporidium parvum

    Science.gov (United States)

    Fayer, R.; Trout, J.M.; Walsh, E.; Cole, R.A.

    2000-01-01

    Six genera of rotifers including Philodina, Monostyla, Epiphanes, Euchlanis, Brachionus, and Asplanchna were exposed to oocysts of Cryptosporidium parvum cleaned of fecal debris. Unstained oocysts and those stained with fluorescein-conjugated monoclonal antibody were added to suspensions of viable rotifers and were examined by phase-contrast, differential interference contrast, and fluorescence microscopy. Rotifers of all six genera were observed ingesting oocysts. A maximum of 25 oocysts was observed in the stomachs of Euchlanis and Brachionus. Euchlanis and Epiphanes were observed excreting boluses containing up to eight oocysts. It was not determined whether rotifers digested or otherwise rendered oocysts nonviable.

  14. Effects of commercial enrichment products on fatty acid components ...

    African Journals Online (AJOL)

    This study was undertaken to test the effects of enrichment products. Red pepper paste (ZA), AlgaMac 3050 (ZB) and Spresso (ZC) on fatty acid compositions in rotifers (Brachionus plicatilis) which were intensively cultured on a mixture of ω3 algae and ω3 yeast. Enriched rotifers were seen to have higher level of ...

  15. Dicty_cDB: Contig-U05205-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 2079.fwd ABWZ Phakopsora pachyrhizi infec... 38 3e-04 3 ( EC368739 ) G840P313FD5.T0 Oscarella carmela pSport...04 3 ( FM901924 ) Brachionus plicatilis EST 5' end, clone sb101P001... 52 4e-04 2 ( EC369115 ) G840P313RD5.T0 Oscarella carmela pSpor

  16. Incidence of feeding, growth and survival of the toothed carp ...

    African Journals Online (AJOL)

    ... larvae raised on B. calyciflorus at the end of the experiment. The fresh water rotifer, B. calyciflorus is an important live food organism for raising of the toothed carp, Aphyosemion gardneri. Keywords: rotifer, Brachionus calyciflorus, larvae, algae, growth commercial diet, survival. Tropical Freshwater Biology 2003/2004 Vol.

  17. FO-spectra of chlorophyll fluorescence for the determination of zooplankton grazing

    NARCIS (Netherlands)

    Lürling, M.; Verschoor, A.M.

    2003-01-01

    In the PHYTO-PAM phytoplankton analyzer the minimal fluorescence of dark-adapted samples (F0) was assessed, which gives direct information on the chlorophyll- a content. Clearance rates (CR) of Daphnia and Brachionus were calculated from a decrease in chlorophyll-a concentration using the PHYTO-PAM

  18. Responses in sediment bioassays used in the Netherlands: can observed toxicity be explained by routinely monitored priority pollutants?

    NARCIS (Netherlands)

    Lahr, J.; Maas-Diepeveen, J.L.; Stuijfzand, S.C.; Leonards, P.E.G.; Drueke, J.M.; Luecker, S.; Espeldoorn, A.

    2003-01-01

    In order to identify the cause of toxicity in sediments and suspended matter, a large number of samples with different degrees of contamination was taken at various locations in The Netherlands. Standard acute bioassays were carried out with the bacterium Vibrio fischeri, the rotifer Brachionus

  19. Ecological factors affecting the distribution of zooplankton ...

    African Journals Online (AJOL)

    Results show that the state of the lagoon is a hyper-eutrophic environment, characterized by high levels of chlorophyll-a and nitrogen. Pollution-tolerant zooplankton such as Brachionus was the dominant species in the lagoon. A total of 61 taxa were recorded, including 35 rotifers, 13 copepods, 5 ostracods, 6 protozoa and ...

  20. Some aspects of the culture, population dynamics and reproductive ...

    African Journals Online (AJOL)

    Journal of Aquatic Sciences ... The effectiveness of using freshwater Chlorella, mixed algae, lettuce leaves and supplemental baker's yeast for the culture of freshwater rotifer, Brachionus calyciflorus were evaluated every two days for 18 days culture ... Addition of baker's yeast improved and sustained rotifer populations.

  1. Assessment of the toxicity of the solid coating PV1 in a marine invironment, using biotests with algae, a rotifer and a bacteria

    NARCIS (Netherlands)

    Foekema, E.M.; Sneekes, A.C.

    2007-01-01

    The toxic potential of substances that may leach from the solid coating PV1 was tested using • the marine bacteria Vibrio fisheri in the Microtox® Basic test • the marine algae Skeletonema costatum in a 72h algal growth inhibition test • the marine rotifer Brachionus plicatilis in the 24 h ROTOX®

  2. Western Indian Ocean Journal of Marine Science - Vol 3, No 1 (2004)

    African Journals Online (AJOL)

    DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. J Robinson, M Isidore, MA Marguerite, MC Őhman, RJ Payet, 63-69. Metazoan Parasites of Some Commercially Important Fish along the Kenyan Coast. PA Aloo, RO Anam, JN Mwangi. Preliminary Study on Hatching of Rotifers (Brachionus plicatilis) and Copepods ...

  3. USING ROTIFER POPULATION DEMOGRAPHIC PARAMETERS TO ASSESS IMPACTS OF THE DEGRADATION PRODUCTS FROM TRINITROTOLUENE PHYTOREMEDIATION

    Science.gov (United States)

    The objective of this study was to evaluate the aquatic chronic lethal and sublethal toxicity effects from the phytoremediation of water contaminated with 2,4,6-trinitrotoluene (2,4,6-TNT) by the wetland plant species Myriophyllum aquaticum (parrot feather). Rotifers (Brachionus...

  4. Fo-spectra of chlorophyll fluorescence for the determination of zooplankton grazing

    NARCIS (Netherlands)

    Lürling, M.F.L.L.W.; Verschoor, A.M.

    2003-01-01

    In the PHYTO-PAM phytoplankton analyzer the minimal fluorescence of dark-adapted samples (F-0) was assessed, which gives direct information on the chlorophyll-a content. Clearance rates (CR) of Daphnia and Brachionus were calculated from a decrease in chlorophyll-a concentration using the PHYTO-PAM

  5. Seasonal Variation of Biomass and Secondary Production of ...

    African Journals Online (AJOL)

    Monthly net samples were taken at inshore and midlake sites in Lake Kuriftu from August 2008 to May 2009 to estimate biomass of the dominant zooplankton, the cyclopoid copepod (Thermocyclops consimilis, 71% in abundance) and the rotifer Brachionus calyciflorus (12%). T. consimilis was cultured in the laboratory to ...

  6. An experimental study on food and salinity preferences of two ...

    African Journals Online (AJOL)

    Effects of feeding on four algal species (Chlorella vulgaris, Nannochloropsis oculata, Isochrysis galbana and Scenedesmus obliques) at salinities of 5, 15 and 25 on the population growth parameters of two Iranian strains of the widespread rotifer species Brachionus plicatilis were examined. Maximum specific growth rate of ...

  7. Genotype versus phenotype variability in Chlorella and Micractinium (Chlorophyta, Trebouxiophyceae).

    Science.gov (United States)

    Luo, Wei; Pflugmacher, Stephan; Pröschold, Thomas; Walz, Norbert; Krienitz, Lothar

    2006-08-01

    The most recent revision of the genus Chlorella, based on biochemical and SSU rDNA analyses, suggested a reduction to a set of four "true" spherical Chlorella species, while a growing number of morphologically different species such as Micractinium (formerly Micractiniaceae) were found to cluster within the clade of "true"Chlorella. In this study, the generic concept in Chlorellaceae to Chlorella and Micractinium was evaluated by means of combined SSU and ITS-2 rDNA sequence analyses and biotests to induce development of bristles on the cell wall. Molecular phylogenetic analyses of Chlorella and Micractinium strains confirmed their separation into two different genera. In addition, non-homoplasious synapomorphies (NHS) and compensatory base changes (CBC) in the secondary structures of SSU and ITS-2 rDNA sequences were found for both genera using this approach. The Micractinium clade can be differentiated into three different genotypes. Using culture medium of the rotifer Brachionus calyciflorus, phenotypic plasticity in Chlorella and Micractinium was studied. Non-bristled Micractinium cells developed bristles during incubation with Brachionus culture medium, whereas Chlorella did not produce bristles. Grazing experiments with Brachionus showed the rotifer preferred to feed on non-bristled cells. The dominance of colonies versus solitary cells in the Micractinium culture was not correlated with the "Brachionus factor". These results suggest that morphological characteristics like formation of bristles represent phenotypic adaptations to the conditions in the ecosystem.

  8. Zooplankton Composition and Abundance as Indicators of Eutrophication in Two Small Man-made Lakes.

    Science.gov (United States)

    Ismail, Azma Hanim; Adnan, Anis Amalina Mohd

    2016-11-01

    The distribution and abundance of zooplankton species of Harapan and Aman Lakes were investigated in relation to physical parameters and chlorophyll- a content. Both lakes were characterised by the occurrence of algal bloom problem. The composition of zooplankton was collected at monthly intervals from November 2013 to February 2014. The total number of taxa in Harapan and Aman Lakes were 23 and 27, respectively. Rotifera was the highest abundance group represent 64% of the total species recorded followed by Copepoda (29%) and Cladocera (7%). Three dominant zooplankton that been recorded in both the lakes are Brachionus forficula , Brachionus nilsoni, and Trichocerca sp. High abundance of these species indicates that the lakes are eutrophic water bodies. Overall, zooplankton species distribution and abundance in the study sites are influenced by various environmental factors such as water transparency and chlorophyll- a content.

  9. Experimental and mathematical model of the interactions in the mixed culture of links in the "producer-consumer" cycle

    Science.gov (United States)

    Pisman, T. I.; Galayda, Ya. V.

    The paper presents experimental and mathematical model of interactions between invertebrates the ciliates Paramecium caudatum and the rotifers Brachionus plicatilis and algae Chlorella vulgaris and Scenedesmus quadricauda in the producer -- consumer aquatic biotic cycle with spatially separated components The model describes the dynamics of the mixed culture of ciliates and rotifers in the consumer component feeding on the mixed algal culture of the producer component It has been found that metabolites of the algae Scenedesmus produce an adverse effect on the reproduction of the ciliates P caudatum Taking into account this effect the results of investigation of the mathematical model were in qualitative agreement with the experimental results In the producer -- consumer biotic cycle it was shown that coexistence is impossible in the mixed algal culture of the producer component and in the mixed culture of invertebrates of the consumer component The ciliates P caudatum are driven out by the rotifers Brachionus plicatilis

  10. Deepor Beel revisited: new records of rotifers (Rotifera: Eurotatoria with remarks on interesting species

    Directory of Open Access Journals (Sweden)

    B.K. Sharma

    2011-01-01

    Full Text Available Plankton samples collected (April 2009 - March 2010 from Deepor Beel, a Ramsar site, revealed 21 species of the Phylum Rotifera belonging to 12 genera and eight families as new records. Amongst these, Brachionus durgae is a new record for northeastern India. The recorded species included the Australasian Brachionus dichotomus reductus and Notommata spinata; two Oriental endemics, namely, Keratella edmondsoni and Lecane blachei while Lecane lateralis, L haliclysta, Lepadella benjamini, Platyias leloupi, Mytilina acanthophora, Macrochaetus longipes, Trichocerca bicristata and T. flagellata are examples of regional distribution interest. The present report increases the number of species recorded from this important wetland of northeastern India to 134 species which, in turn, is the richest rotifer diversity known till date from any aquatic ecosystem of South Asia.

  11. Development of a Method to Determine the Number of Viable Organisms >or- 50 micrometers (Nominally Zooplankton) in Ships’ Ballast Water: A Combination of Two Vital, Fluorescent Stains

    Science.gov (United States)

    2010-04-23

    viability of cultured brine shrimp (Artemia franciscana) and cultured rotifers (Brachionus plicatilis). This technique, however, has not been as...concentrated using a 50 µm nylon mesh sieve. 2.2 Standard Test Organisms The brine shrimp Artemia franciscana has been used extensively in...aquaculture and research for decades due to the widespread retail sale of cysts and the ease of hatching ( Brine Shrimp Direct, Ogden, UT). To hatch the

  12. The Use of the Schizonticidal Agent Quinine Sulfate to Prevent Pond Crashes for Algal-Biofuel Production

    OpenAIRE

    Chunyan Xu; Kangyan Wu; Van Ginkel, Steve W.; Thomas Igou; Hwa Jong Lee; Aditya Bhargava; Rachel Johnston; Terry Snell; Yongsheng Chen

    2015-01-01

    Algal biofuels are investigated as a promising alternative to petroleum fuel sources to satisfy transportation demand. Despite the high growth rate of algae, predation by rotifers, ciliates, golden algae, and other predators will cause an algae in open ponds to crash. In this study, Chlorella kessleri was used as a model alga and the freshwater rotifer, Brachionus calyciflorus, as a model predator. The goal of this study was to test the selective toxicity of the chemical, quinine sulfate (QS)...

  13. Rotiferan Hox genes give new insights into the evolution of metazoan bodyplans

    OpenAIRE

    Andreas C Fröbius; Funch, Peter

    2017-01-01

    The phylum Rotifera consists of minuscule, nonsegmented animals with a unique body plan and an unresolved phylogenetic position. The presence of pharyngeal articulated jaws supports an inclusion in Gnathifera nested in the Spiralia. Comparison of Hox genes, involved in animal body plan patterning, can be used to infer phylogenetic relationships. Here, we report the expression of five Hox genes during embryogenesis of the rotifer Brachionus manjavacas and show how these genes define different ...

  14. Potential for Biomagnification of Contaminants within Marine and Freshwater Food Webs

    Science.gov (United States)

    1984-11-01

    concentrations of the PCB in algae ( Dunaliella sp.), rotifers (Brachionus plicatilis), and larval anchovies (Engraulis mordax) were 0.25, 0.42, and...of Metals in Algae (Nacrocysti3 pyrifera) and in Feces of Crabs (Pugettia producta) Fed Algae , and Theoretical Retention of Metals by the Crabs...Spring Water, Algae , and Micro- crustacea in a Laboratory Microcosm ..... .............. .. 109 21 Copper and Zinc Concentrations in Sediments and

  15. Perca fluviatilis L.

    African Journals Online (AJOL)

    AISA

    Pour une meilleure survie, les larves de la perche fluviatile Perca fluviatilis L., qui sont en général de petite taille, ont été nourries, dès l'éclosion, avec deux proies vivantes : le Rotifère d'eau douce (Brachionus calyciflorus) et le nauplii d'Artemia salina. Pour minimiser les mortalités dues aux manipulations des larves.

  16. Goplers relative trofiske niveau bestemt ved δ15N

    DEFF Research Database (Denmark)

    Christensen, Jens Tang; Sode, Sidsel; Krawack, Marie-Louise

    , hvor den indbyrdes afstand mellem to arter er bestemt på samme tid og i samme vandmasse. I laboratorieforsøg har Aurelia vist lave værdier for trofisk berigelse (forskel på fødens og Aurelias 15N) på 0,74 ‰ for Artemia, 0,99 ‰ for Brachionus og 0,58 ‰ for skrubbelarver. Dette bør undersøges i flere...

  17. Evaluation of primary and secondary production using wastewater as a culture medium.

    Science.gov (United States)

    Nandini, S; Ramírez-García, Pedro; Sarma, S S S

    2010-10-01

    The ability of rotifers and cladocerans to convert primary to secondary production in wastewaters was tested. Scenedesmus acutus was cultured on Bold's (defined) medium, wastewater from the tertiary phase of water treatment and a mixture of both. The algal growth rates (µ) ranged from 0.4 to 0.7 day⁻¹, being highest in defined medium. The demographic characteristics of Brachionus rubens and Moina macrocopa were tested using algae at a density of 1.0 x 10⁶ cells mL⁻¹. Into each test jar, we introduced 20 neonates (medium on which the algae was cultured; in the case of B. rubens, they ranged from 20-36 and 10-22 offspring female⁻¹; the corresponding values for M. macrocopa were higher (38-110 and 13-31 offspring female⁻¹, respectively). The rate of population increase was higher for Brachionus (0.41-0.65 day⁻¹)) compared to Moina (0.28-0.57 day⁻¹). Brachionus had significantly higher growth rates on algae cultured on Bold medium than on treated wastewater while Moina grew significantly better on Scenedesmus cultured on Bold medium or a mixture of treated wastewater and Bold medium than on treated wastewater alone.

  18. The effect of seasonality on the structure of rotifers in a black-water shallow lake in Central Amazonia.

    Science.gov (United States)

    Nova, Clarice C; Lopes, Vanessa G; Souza, Leonardo Coimbra E; Kozlowsky-Suzuki, Betina; Pereira, Talita A A; Branco, Christina W C

    2014-09-01

    Rotifers have often been used as indicators of sudden changes in physical and chemical features of the aquatic environment. Such features vary greatly during flood pulse events in small lakes connected to major floodplains. However, few are the studies that investigate the consequences of the flood pulse in rotifer species composition, abundance, richness and diversity, especially in Amazonian lakes. We analyzed samples from a small blackwater lake of an "igarapé" connected permanently to the Negro river, in Central Amazonia. Samples were taken twice a year for two years, comprising flooding and receding periods of the flood pulse. Rotifer abundance increased significantly after draught events, and electrical conductivity and turbidity were intrinsically related to such variation. Species composition also changed from flooding to receding periods. Some taxa, such as Brachionus zahniseri reductus and Lecane remanei were restricted to receding periods, while Brachionus zahniseri, Brachionus gillardi and Lecane proiecta were only present during flooding. A shift in the composition of rotifer families was observed from one period to another, showing the effect of renewing waters of the flood pulse. These results suggest that the flood pulse acts as a driving force and stressing condition, considerably altering rotifer community dynamics, either changing species composition or decreasing abundance.

  19. First feeding of Eugerres brasilianus (Carapeva larvae with Acartia tonsa (Copepod nauplii increases survival and resistance to acute stress

    Directory of Open Access Journals (Sweden)

    Wanessa de Melo Costa

    2016-01-01

    Full Text Available The rotifer Brachionus sp. is commonly used for larval feeding in marine fish hatcheries. The aim of this study was to evaluate whether the inclusion of Acartia tonsa nauplii in the initial diet of carapeva larvae improves their survival, growth and resistance to stress when compared to the regimen containing only rotifers. Adult copepods were collected in the wild and cultured with the microalgae Chaetoceros muelleri, Isochrysis galbana and Nannochloropsis oculata to obtain nauplii. Carapeva larvae were grown for 15 days using four treatments and three replicates: 1 Brachionus plicatilis rotifers (10 to 15/mL; 2 A. tonsa nauplii (0.25 to 0.5/mL; 3 Brachionus plicatilis rotifers (5 to 7.5/mL + A. tonsa nauplii (0.12 to 0.25/mL, and 4 no supply of live feed. After 15 days, the carapeva larvae were subjected to stress by exposure to air for 10 seconds and then returned to the source tank to evaluate survival after 24 h. Survival and stress resistance were higher in carapeva larvae fed B. plicatilis + A. tonsa nauplii (P<0.05, 20.9 ± 11.2% and 88.9%, respectively. These results confirm the positive effect of the inclusion of copepod nauplii in the diet of fish larvae. However, more research is needed to validate these results.

  20. Rotiferan Hox genes give new insights into the evolution of metazoan bodyplans

    DEFF Research Database (Denmark)

    Andreas, Fröbius C.; Funch, Peter

    2017-01-01

    , can be used to infer phylogenetic relationships. Here, we report the expression of five Hox genes during embryogenesis of the rotifer Brachionus manjavacas and show how these genes define different functional components of the nervous system and not the usual bilaterian staggered expression along...... the anteroposterior axis.Sequence analysis revealed that the lox5 parapeptide, a key signature in lophotrochozoan and platyhelminthean Hox6/lox5 genes, is absent and replaced by different signatures in Rotifera and Chaetognatha, and that the MedPost gene, until now unique to Chaetognatha, is also present in rotifers...

  1. Seasonal variations of rotifers from a high altitude urban shallow water body, La Cantera Oriente (Mexico City, Mexico)

    Science.gov (United States)

    Gutiérrez, Sergio González; Sarma, S. S. S.; Nandini, S.

    2017-11-01

    La Cantera Oriente is a shallow freshwater volcanic water body located at an altitude of 2 270 m above sea level in the Ecological Reserve of San Angel Pedregal of Mexico City (Mexico). In order to ensure the conservation of its biological heritage including zooplankton, the present work was undertaken to quantify the seasonal changes in the diversity and density of rotifers and the selected physico-chemical variables during 2013-2014. Qualitative analysis of the zooplankton samples yielded 68 rotifer species which represented 24 genera in 15 families. B rachionus calyciflorus Pallas, 1766, B. quadridentatus Hermann, 1783, Polyarthra vulgaris Carlin, 1943, Lecane closterocerca (Schmarda, 1859) and Keratella cochlearis (Gosse, 1851) were the most common species. Preston plots of species frequency-density revealed that as many as 30% of the rotifer taxa were dominant throughout the year. The species with high population densities were Brachionus quadridentatus, Lecane closterocerca, Keratella cochlearis, and Lepadella patella; their peak densities were 2 000, 1 000, 180 and 90 ind./L, all occurring in summer. Canonical correspondence analysis showed that Platyias quadricornis was related to the concentration of phosphates available in the environment and the conductivity, while B. quadridentatus was positively correlated with chlorophyll- a. The trophic status of the lake was eutrophic based on Chl- a content but oligotrophic with relation to the Brachionus: Trichocerca ratio.

  2. Toxicity of two imidazolium ionic liquids, [bmim][BF4] and [omim][BF4], to standard aquatic test organisms: Role of acetone in the induced toxicity.

    Science.gov (United States)

    Tsarpali, Vasiliki; Dailianis, Stefanos

    2015-07-01

    The main goal of this study was to investigate the toxicity of the imidazolium-based ionic liquids (ILs), [bmim][BF4] (1-butyl-3-methylimidazolium tetrafluoroborate) and [omim][BF4] (1-octyl-3-methylimidazolium tetrafluoroborate), in battery of standard aquatic toxicity test organisms. Specifically, exposure of the algae Scenedesmus rubescens, crustaceans Thamnocephalus platyurus and Artemia franciscana, rotifers Brachionus calyciflorus and Brachionus plicatilis and bivalve Mytilus galloprovincialis to different concentrations of [bmim][BF4], [omim][BF4] and/or a binary mixture of [bmim][BF4]-[omim][BF4] (1:1) with or without acetone (carrier solvent), revealed that solvent can differentially mediate ILs' toxic profile. Acetone's ability to differentially affect ILs' cation's alkyl chain length, as well as the hydrolysis of [BF4(-)] anions was evident. Given that the toxic potency of the tested ILs seemed to be equal or even higher (in some cases) than those of conventional organic solvents, the present study revealed that the characterization of imidazolium-based ILs as "green solvents" should not be generalized, at least in case of their natural occurrence in mixtures with organic solvents, such as acetone. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. The diversity of Indian Brachionidae (Rotifera: Eurotatoria: Monogononta and their distribution

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    B.K. Sharma

    2014-11-01

    Full Text Available We evaluate diversity status of the Brachionidae of India and present an annotated checklist of 46 species excluding dubious and unconfirmed reports. These merit biodiversity value as ~27% of the global diversity of the taxon and ~81% of its Oriental species. We observed two Australasian elements, two Oriental endemics, one Indian endemic, one paleotropical and one cosmo (sub tropical species. The cold-water Keratella serrulata and Notholca squamula are new records from eastern Himalayas. Maximum brachionid diversity (32 species from Assam state of northeast India (NEI is followed by the reports of 27 and 26 species from Tamil Nadu and West Bengal, respectively; 25 species each from Tripura and Maharashtra; and 24 species from Jammu & Kashmir. Brachionus, the most diverse brachionid genus, is widely distributed in India with low richness in hill states of NEI and coastal waters in particular. The Indian brachionid taxonomy is confounded with unconfirmed reports, misidentifications, invalid taxa, and inconsistent treatment of morphological variants, while analysis of cryptic diversity in Brachionus calyciflorus, B. caudatus, B. forficula, B. plicatilis, B. quadridentatus, B. urceolaris, Keratella cochlearis and K. quadrata species-groups awaits attention.

  4. Feeding and filtration rates of zooplankton (rotifers and cladocerans) fed toxic cyanobacterium (Microcystis aeruginosa).

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    Pérez-Morales, Alfredo; Sarma, S S S; Nandini, S

    2014-11-01

    Microcystis aeruginosa is generally dominant in many Mexican freshwater ecosystems interacting with zooplankton species. Hence, feeding and filtration rates were quantified for three cladoceran (Daphnia pulex, Moina micrura and Ceriodaphnia dubia) and three rotifer species (Brachionus calyciflorus, Brachionus rubens and Plationus patulus) using sonicated M. aeruginosa alone or mixed with Scenedesmus acutus in different proportions (25, 50 and 75%, based on cell density), offering a combined initial density of 100,000 cells·ml(-1). All the three cladoceran species ingested M. aeruginosa (100-300 cells ind(-1) min(-1)) when fed exclusively with cyanobacterium. When green alga offered as exclusive diet, the number of cells ingested by the tested cladocerans varied from 80 to 400 cells ind(-1) min(-1). Compared to cladocerans, rotifers in general consumed much lower quantity (rotifer species, P. patulus filtered highest volume (100 μl ind(-1) min(-1) from mixed diets containing higher proportions (50 or 75%) of M. aeruginosa. Thus, there were species-specific differences in the filtration and feeding rates of zooplankton when offered mixed diets of green algae and toxic cyanobacteria. These probably explain the coexistence of different zooplankton species in Microcystis-dominant waterbodies.

  5. The Use of the Schizonticidal Agent Quinine Sulfate to Prevent Pond Crashes for Algal-Biofuel Production.

    Science.gov (United States)

    Xu, Chunyan; Wu, Kangyan; Van Ginkel, Steve W; Igou, Thomas; Lee, Hwa Jong; Bhargava, Aditya; Johnston, Rachel; Snell, Terry; Chen, Yongsheng

    2015-11-17

    Algal biofuels are investigated as a promising alternative to petroleum fuel sources to satisfy transportation demand. Despite the high growth rate of algae, predation by rotifers, ciliates, golden algae, and other predators will cause an algae in open ponds to crash. In this study, Chlorella kessleri was used as a model alga and the freshwater rotifer, Brachionus calyciflorus, as a model predator. The goal of this study was to test the selective toxicity of the chemical, quinine sulfate (QS), on both the alga and the rotifer in order to fully inhibit the rotifer while minimizing its impact on algal growth. The QS LC50 for B. calyciflorus was 17 µM while C. kessleri growth was not inhibited at concentrations algae farmers an important tool to manage grazing predators in algae mass cultures and avoid pond crashes.

  6. Competition between links in "producer-consumer" trophic chains in an aquatic closed system with spatially separated components.

    Science.gov (United States)

    Pisman, T I; Pechurkin, N S; Somova, L A

    2001-01-01

    The work analyzes functioning of a "producer-consumer" closed aquatic system with spatially separated links, where each component consisted of two species. Producers in the system were the microalgae of Chlorella vulgaris and Scenedesmus sp., consumers--Paramecium caudatum infusoria and Brachionus sp. rotifers. In the experiment the competing predators were consuming on a mixed culture of algae, and the competition of algae was studied under nitrogen limitation. Under these conditions competitiveness of Scenedesmus was higher than that of Chlorella vulgaris. Metabolism products of Scenedesmus algae have been found to have negative effect on reproduction of Paramecium caudatum protozoa. Predator population dynamics in the "consumer" link demonstrated that the rotifers that consume two algal species are more competitive compared to protozoa feeding on chlorella only. Grant numbers: N99-04-96017, N25. c 2001. COSPAR. Published by Elsevier Science Ltd. All rights reserved.

  7. Competition between links in ``producer-consumer'' trophic chains in an aquatic closed system with spatially separated components

    Science.gov (United States)

    Pisman, T. I.; Pechurkin, N. S.; Somova, L. A.

    The work analyzes functioning of a "producer-consumer" closed aquatic system with spatially separated links, where each component consisted of two species. Producers in the system were the microalgae of Chlorella vulgaris and Scenedesmus sp., consumers - Paramecium caudatum infusoria and Brachionus sp. rotifers. In the experiment the competing predators were consuming on a mixed culture of algae, and the competition of algae was studied under nitrogen limitation. Under these conditions competitiveness of Scenedesmus was higher than that of Chlorella vulgaris. Metabolism products of Scenedesmus algae have been found to have negative effect on reproduction of Paramecium caudatum protozoa. Predator population dynamics in the "consumer" link demonstrated that the rotifers that consume two algal species are more competitive compared to protozoa feeding on chlorella only.

  8. First report of freshwater rotifers (Rotifera: Eurotatoria from south Andaman, India: Composition and interesting elements

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    Bhushan Kumar Sharma

    2017-06-01

    Full Text Available Plankton samples collected from freshwater lentic ecosystems of south Andaman, India, revealed 70 species of Rotifera belonging to 25 genera and 16 families. The reports of Australasian Lecane batillifer, Oriental endemic Lecane bulla diabolica and three Paleotropical species, and 68 new records of Eurotatoria from Andaman and Nicobar Islands contribute to biodiversity and biogeography of the Indian Rotifera. The rotifers are characterized by diverse Lecanidae>Lepadellidae>Brachionidae and common nature of species of “tropic-centered” Lecane and Brachionus. The occurrences of a large number of cosmopolitan species, and several tropicopolitan and pantropical species are notable. This report indicates a further scope for biodiversity update on these metazoans from the insular freshwater of Andaman and Nicobar Islands located in the Andaman Sea.

  9. Phototransformation of Amlodipine in Aqueous Solution: Toxicity of the Drug and Its Photoproduct on Aquatic Organisms

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    Marina DellaGreca

    2007-01-01

    Full Text Available The phototransformation of amlodipine in water was investigated under various conditions. A quantum yield ΦS2.2×10−4 and a half-life time t1/2 0.419 days were calculated when the drug in water (10−4 M was exposed to sunlight. The only photoproduct found was its pyridine derivative. Formation of this product was explained on the basis of a radical cation intermediate. The acute and chronic toxicity of the drug and its photoproduct were evaluated on different organisms of the freshwater chain (Brachionus calyciflorus, Thamnocephalus platyurus, Daphnia magna, Ceriodaphnia dubia. The photoproduct exhibited a stronger toxic potential than the parent drug on the long time for C. dubia.

  10. Shifts in rotifer life history in response to stable isotope enrichment: testing theories of isotope effects on organismal growth.

    Science.gov (United States)

    Gorokhova, Elena

    2017-03-01

    In ecology, stable isotope labelling is commonly used for tracing material transfer in trophic interactions, nutrient budgets and biogeochemical processes. The main assumption in this approach is that the enrichment with a heavy isotope has no effect on the organism growth and metabolism. This assumption is, however, challenged by theoretical considerations and experimental studies on kinetic isotope effects in vivo. Here, I demonstrate profound changes in life histories of the rotifer Brachionus plicatilis fed 15N-enriched algae (0.4-5.0 at%); i.e. at the enrichment levels commonly used in ecological studies. These findings support theoretically predicted effects of heavy isotope enrichment on growth, metabolism and ageing in biological systems and underline the importance of accounting for such effects when using stable isotope labelling in experimental studies.

  11. Experimental and mathematical model of the interactions in the mixed culture of links in the “producer-consumer” cycle

    Science.gov (United States)

    Pisman, T. I.

    2009-07-01

    The paper presents a experimental and mathematical model of interactions between invertebrates (the ciliates Paramecium caudatum and the rotifers Brachionus plicatilis) in the "producer-consumer" aquatic biotic cycle with spatially separated components. The model describes the dynamics of the mixed culture of ciliates and rotifers in the "consumer" component, feeding on the mixed algal culture of the "producer" component. It has been found that metabolites of the algae Scenedesmus produce an adverse effect on the reproduction of the ciliates P. caudatum. Taking into account this effect, the results of investigation of the mathematical model were in qualitative agreement with the experimental results. In the "producer-consumer" biotic cycle it was shown that coexistence is impossible in the mixed culture of invertebrates of the "consumer" component. The ciliates P. caudatum are driven out by the rotifers B. plicatilis.

  12. The zooplankton biodiversity of some freshwater environments in Parnaíba basin (Piauí, Northeastern Brazil

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    JDN. Paranhos

    Full Text Available The plankton fauna of the state of Piauí, Northeastern Brazil, especially in the Parnaíba basin, is still poorly known; the results of most studies of the subject have not been published and can only be found in grey literature (unpublished scientific works, such as course completion work and consulting reports. Thus, this paper presents data from samples taken recently from different water bodies in Piauí and represents the second study to be published on the region's zooplankton since the pioneering work of Spandl (1926. A total of 38 species were recorded, including 23 new occurrences of rotifers, 10 of cladocerans and 2 of copepods for the state of Piauí. The greatest richness was observed for the rotifers, of which the genus Brachionus must be highlighted, especially at the Joana reservoir. Among the crustaceans, the greatest richness was observed at the Bezerra reservoir, where cladocerans of the genus Bosmina were prominent. The rotifers Brachionus havanaensis Rousselet, 1911 and Filinia longiseta (Ehrenberg, 1834; the cladocerans Diaphanosoma spinulosum Herbst, 1967 and Moina micrura Kurz, 1874; and the copepods Notodiaptomus cearensis Wright, 1936 and Thermocyclops decipiens Kiefer, 1927 occurred in all or in most environments in which the respective groups were studied. The results presented here expand the taxonomic list of zooplankton for the state of Piauí, including a total fauna of 30 species of rotifers, 15 of cladocerans and 3 of copepods. The zooplankton richness was considered low in the studied reservoirs compared to other freshwater ecosystems from Northeastern Brazil; however, the few studies developed in the Parnaíba basin suggest that the diversity for these organisms should be higher.

  13. Species-specific separation of lake plankton reveals divergent food assimilation patterns in rotifers.

    Science.gov (United States)

    Burian, Alfred; Kainz, Martin J; Schagerl, Michael; Yasindi, Andrew

    2014-06-01

    1. The analysis of functional groups with a resolution to the individual species level is a basic requirement to better understand complex interactions in aquatic food webs. Species-specific stable isotope analyses are currently applied to analyse the trophic role of large zooplankton or fish species, but technical constraints complicate their application to smaller-sized plankton. 2. We investigated rotifer food assimilation during a short-term microzooplankton bloom in the East African soda lake Nakuru by developing a method for species-specific sampling of rotifers. 3. The two dominant rotifers, Brachionus plicatilis and Brachionus dimidiatus, were separated to single-species samples (purity >95%) and significantly differed in their isotopic values (4.1‰ in δ(13)C and 1.5‰ in δ(15)N). Bayesian mixing models indicated that isotopic differences were caused by different assimilation of filamentous cyanobacteria and particles importance of species-specific sampling of smaller plankton compartments. 4. A main difference was that the filamentous cyanobacterium Arthrospira fusiformis, which frequently forms blooms in African soda lakes, was an important food source for the larger-sized B. plicatilis (48%), whereas it was hardly ingested by B. dimidiatus. Overall, A. fusiformis was, relative to its biomass, assimilated to small extents, demonstrating a high grazing resistance of this species. 5. In combination with high population densities, these results demonstrate a strong potential of rotifer blooms to shape phytoplankton communities and are the first in situ demonstration of a quantitatively important direct trophic link between rotifers and filamentous cyanobacteria.

  14. Rotifer community structure and assessment of water quality in Yangcheng Lake

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    Chen, Lijing; Liu, Qiao; Peng, Ziran; Hu, Zhongjun; Xue, Junzeng; Wang, Wu

    2012-01-01

    Rotifer community structure was investigated in Yangcheng Lake in 2008. Dominant species and species diversity indices were determined and Q B/T was used to assess water quality. The annual average density and biomass of the rotifers in Yangcheng Lake was 2 894 ± 1 006 ind./L and 12.47 ± 10.28 mg/L, respectively. The highest densities were observed in the western portion of the lake in March, but the highest biomass occurred in inflowing creeks in September. Within a year of monitoring in Yangcheng Lake, 93 species were identified and the dominant species were found to be Polyarthra trigla, Brachionus angularis, Keratella cochlearis, Keratella valga, Brachionus calyciflorus, and Filinia major. Of the species recorded, 75 were pollution indicator species. Density and biomass exhibited significant positive correlations with water temperature ( R = 0.209, P = 0.003; R = 0.446, P = 0.000), but the peak density showed two lags in response to chl a. According to the Jaccard similarity index ( S J), the greatest similarity among dominant species occurred between creeks and the eastern part of the lake. The annual average Shannon-Wiener diversity index H', Margalef richness index D and Pielou evenness index J were 1.96 ± 0.34, 1.61 ± 0.50 and 0.77 ± 0.10, respectively. In all four areas of Yangcheng Lake, β-mesosaprobic species comprised the largest share of pollution indicator species. These data suggest that Yangcheng Lake is mesosaprobic.

  15. Determination of trace elements in freshwater rotifers and ciliates by total reflection X-ray fluorescence spectrometry

    Science.gov (United States)

    Woelfl, S.; Óvári, M.; Nimptsch, J.; Neu, T. R.; Mages, M.

    2016-02-01

    Element determination in plankton is important for the assessment of metal contamination of aquatic environments. Until recently, it has been difficult to determine elemental content in rotifers or ciliates derived from natural plankton samples because of the difficulty in handling and separation of these fragile organisms. The aim of this study was to evaluate methods for separation of rotifers and large ciliates from natural plankton samples (μg range dry weight) and subsequent analysis of their elemental content using total-reflection X-ray fluorescence spectrometry (TXRF). Plankton samples were collected from different aquatic environments (three lakes, one river) in Chile, Argentina and Hungary. From one to eighty specimens of five rotifer species (Brachionus calyciflorus, Brachionus falcatus, Asplanchna sieboldii, Asplanchna sp., Philodina sp.) and four to twelve specimens of one large ciliate (Stentor amethystinus) were prepared according to the dry method originally developed for microcrustaceans, and analysed by TRXF following in situ microdigestion. Our results demonstrated that it possible to process these small and fragile organisms (individual dry mass: 0.17-9.39 μg ind- 1) via careful washing and preparation procedures. We found species-dependent differences of the element mass fractions for some of the elements studied (Cr, Mn, Fe, Ni, Cu, Zn, As, Pb), especially for Cu, Fe and Mn. One large rotifer species (A. sieboldii) also showed a negative correlation between individual dry weight and the element content for Pb, Ni and Cr. We conclude that our application of the in situ microdigestion-TRXF method is suitable even for rotifers and ciliates, greatly expanding the possibilities for use of plankton in biomonitoring of metal contamination in aquatic environments.

  16. Aquatic ecotoxicology approaches in Western Mexico.

    Science.gov (United States)

    Zavala-Aguirre, Jose L; Torres-Bugarin, Olivia; Zamora-Perez, Ana L

    2007-08-01

    A series of bioindicator organisms for aquatic ecosystems are being maintained under laboratory conditions in order to analyze effects of pollution on aquatic wildlife and potential effects on human health. Growth kinetics of algae Pseudokirchneriella subcapitata was used to evaluate effects of the surfactant nonilphenol (NP). Brachionus calyciflorus was used to set up a model of endocrine disruption using the fungicide vinclozolin (Vc). We exposed salamanders from the genus Ambystoma sp., to different concentrations of both the aneugen colchicine (COL) and the clastogen cyclophosphamide (CP) and we determined the frequency of micronucleated cells (MNC) in their shed skin. The presence of spontaneous micronuclei in peripheral blood erythrocytes from 10 fish species in Lake "La Alberca," Michoacan (Mexico), was evaluated as a possible biological indicator of genotoxic agents. Results confirm the sensivity of Pseudokirchneriella subcapitata to growth kinetics: the range of concentration of NP (20, 200 and 2000 microg L(- 1)) shows an inverted U shape in its maximum growth rate; Dimethyl sulfoxide (DMSO) used as a positive control and to solvate NP induced an inverse stimulatory effect on growth rate in the range of concentrations analyzed (0.0023, 0.023 and 0.23% v v(- 1)). In the use of the rotifer Brachionus calyciflorus, the range of Vc from 0.185 mg L(- 1) to 3 mg L(- 1) clearly showed an inverted U shape characteristic of endocrine disruptions. We were able to use shed skin from Ambystoma sp., to measure MNC frequencies induced either by an aneugenic or a clastogenic compound. The MNC frequency was increased significantly by all doses of COL and CP, administered either as single or repeated exposures. The presence of MNC in the shed skin and the speed of sloughing lead us to propose that the sheds of Ambystoma sp., or other amphibians that slough their skin, as suitable alternative models for detecting genotoxic exposures relevant to aquatic environments. In the

  17. Growth and gastrointestinal indices in Nile tilapia fed with different diets=Crescimento e índices gastrintestinais de tilápia do Nilo alimentadas com diferentes dietas

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    Plácido Soares de Moura

    2012-07-01

    Full Text Available The adequate diet of Nile tilapia in their growth early stages is fundamental to the success of culture subsequent stages. The goal of the present work was to evaluate the Nile tilapia growth fed with different diets, and to morphometrically characterized the gastrointestinal tract of this species. The treatments consisted of three diets: (D1 natural food, (D2, commercial feed and (D3 commercial feed + natural food. In the qualitative phytoplankton analysis, there was greater representation of the genus Chlorella, while zooplankton community analysis revealed greater number of Brachionus rotifer. Growth and survival in D2 and D3 did not reveal differences (p > 0.05, while in D1, the results were significantly lower (p A dieta adequada de tilápia do Nilo em suas fases iniciais de crescimento é fundamental para o sucesso das etapas subsequentes do cultivo. O objetivo do presente trabalho foi avaliar o crescimento de tilápias do Nilo alimentadas com diferentes dietas e caracterizar morfometricamente o aparelho gastrintestinal da espécie. Os tratamentos constaram de três dietas: (D1 alimento natural, (D2 ração comercial e (D3 ração comercial + alimento natural. Na análise qualitativa do fitoplâncton, observou-se maior representação do gênero Chlorella enquanto a análise da comunidade zooplanctônica revelou maior número de rotíferos do gênero Brachionus. O crescimento e a sobrevivência em D2 e D3 não apresentaram diferenças (p > 0.05, enquanto em D1 os resultados foram significativamente inferiores (p < 0.05. Os índices gastrossomáticos, enterossomáticos e o quociente intestinal apresentaram, de uma maneira geral, valores superiores nos tratamentos que utilizaram alimento natural na dieta. Tilápia do Nilo alcançou melhor desempenho zootécnico quando a ração comercial foi incluída na dieta. A ingestão do alimento natural e/ou artificial está relacionada com o desenvolvimento dos índices gastrintestinais, refor

  18. JENIS PAKAN ALAMI LARVA IKAN BETOK (Anabas testudineus Bloch DI PERAIRAN RAWA MONOTON DANAU BANGKAU, KALIMANTAN SELATAN

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    Rukmini Rukmini

    2016-03-01

    Full Text Available Usaha pembenihan ikan merupakan alternatif pemecahan masalah untuk mengatasi kesenjangan antara ketersediaan dan kebutuhan benih dalam budidaya ikan. Keberhasilan usaha pembesaran ikan betok dibatasi oleh tingkat kelangsungan hidup larva bagi pertumbuhan dan jenis pakan alami larva ikan di habitatnya. Tujuan penelitian ini adalah untuk mengetahui jenis dan kelimpahan pakan alami yang dikonsumsi larva ikan betok di perairan rawa monoton Danau Bangkau Kalimantan Selatan. Penelitian dilaksanakan pada bulan Desember 2011-Januari 2012. Pengambilan sampel pakan dan larva dilakukan pada dua tempat yang berbeda pada kedalaman 30 cm. Hasil penelitian menunjukkan jenis plankton yang dikonsumsi oleh larva ikan betok berubah sesuai dengan ukuran bukaan mulut ikan dan kelimpahan plankton di perairan. Jenis plakton dominan yang dimakan oleh larva betok yaitu Mougeotia sp. 265 sel/L diikuti oleh Coconeis sp. 246 sel/L, Keratella sp. 174 sel/L, Chlorococcum sp. 110 sel/L, Brachionus sp. 98 sel/L, dan Navicula sp. 47 sel/L. Jenis plakton dominan yang dimakan berubah sesuai dengan umur larva.   Business seeding fish an alternative problem-solving to overcome the gap between availability and needs seeds. The success of the business of enlargement climbing fish bounded by the degree of continuity larvæ live for growth and a kind of natural fish larvae feed on their habitat. The purpose of this research was to know the type of plankton that were consumed by climbing perch fish larvae in the waters of the monotonous swamp of Danau Bangkau. The research was conducted from December, 2011- January, 2012. The sample feed and larvæ carried on two different places at the depth of 30 cm. The result showed plankton species consumed by climbing fish larvae change according to size openings mouth fish and abundance plankton in waters. A kind of plankton dominant which are eaten by the climbing larvæ  namely Mougeotia sp. 265 cells/L followed by Coconeis sp. 246 cells

  19. Bioestadística como apoyo a la praxis pedagógica de la Zoología de invertebrados en la determinación de Rotíferos de hábitat planctónico en el ecosistema de la laguna del Parque Recreacional de la ciudad de Cúcuta, aplicando las claves dicotómicas para su clasificación.

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    María Eugenia Muñoz-Peñaloza

    2012-01-01

    Full Text Available The study involved the identification and classification of phylum specimens rotifers from planktonic habitat in the recreational lagoon park ecosystem in Cucuta City. Was made a topographic uprising to the lagoon, was distributed in eight areas and physicochemical water analyses were performed. Rotifers were collected and identified in two ways, first, using representative schemes of the most common genera, according to Barnes (1995, Gardiner (1978, Hickman (1995, Arteaga, Herrera (2005, Strebler and Krauter (1987 Iafrancesco (1997 and second, the systematic identification through the application of the dichotomous key to genera, according to James G. Needham And Paul R. Needham (1982. To characterize the presence of rotifers according to zones, we used the frequency distribution, at the rates: Jaccard (presence or absence, Raup-Crick index (similarity in relation to the areas and Margalef index (for diversity. The lagoon water according to the physicochemical parameters and bioindication was classified as beta mesosapria, being secondary contact for recreational purposes. We found six families of rotifers: Brachionidae, Philodinidae, Notommatidae, Synchaetidae, Collotheidae, Lecanidae and ten genera Brachionus, Lepadella, Colurella, Philodina, Rotary, Cephalodella, Trichocerca, Polyartha, Collotheca and Lecane and through the application of biostatistics rotifers were distributed according to areas. The procedures and photographic records developed in the study are a support material, for pedagogical praxis in rotifer phylum topic in invertebrate zoology.

  20. Time and concentration dependency in the potentially affected fraction of species: the case of hydrogen peroxide treatment of ballast water.

    Science.gov (United States)

    Smit, Mathijs G D; Ebbens, Eltjo; Jak, Robbert G; Huijbregtst, Mark A J

    2008-03-01

    Transport of large volumes of ballast water contributes greatly to invasions of species. Hydrogen peroxide (H2O2) can be used as a disinfectant to prevent the spread of exotic species via ballast water. Instead of using environmental risk assessment techniques for protecting a certain fraction of the species from being affected, the present study aimed to apply these techniques to define treatment regimes of H2O2 and effectively eliminate as many species as possible. Based on time-dependent dose-response curves for five marine species (Corophium volutator, Artemia salina, Brachionus plicatilis, Dunaliella teriolecta, and Skeletonema costatum), time-dependent species-sensitivity distributions (SSDs) were derived for different effect sizes. The present study showed that H2O2 can be used effectively to treat ballast water but that relatively high concentrations and long treatment durations are required to eliminate the vast majority of species in ballast water. The described toxicant effectiveness approach using SSDs also has other potential fields of application, including short-term application of biocides.

  1. Adverse effects of the SSRI antidepressant sertraline on early life stages of marine invertebrates.

    Science.gov (United States)

    Estévez-Calvar, Noelia; Canesi, Laura; Montagna, Michele; Faimali, Marco; Piazza, Veronica; Garaventa, Francesca

    2017-07-01

    Widespread contamination of coastal environments by emerging compounds includes low concentrations of pharmaceuticals. These pollutants are not currently incorporated in monitoring programs despite their effects on non-target organisms are very little documented. Among the selective serotonin reuptake inhibitor (SSRI) antidepressants, sertraline (SRT) is one of the most prescribed globally. In this work, earlier life stages of Amphibalanus amphitrite, Brachionus plicatilis and Mytilus galloprovincialis were exposed to environmental concentrations of SRT in order to study both sub-lethal and lethal responses in 24/48 h-tests. Low concentrations of SRT altered significantly swimming behavior in A. amphitrite and B. plicatilis giving 48 h-EC50 (μg/L) of 113.88 and 282.23, respectively whereas higher values were observed for mortality and immobilization. EC50 embryotoxicity with M. galloprovincialis was 206.80 μg/L. This work add new data about SRT ecotoxicity on marine invertebrates and confirms the applicability of behavioral endpoints to evaluate the environmental impact of antidepressants in marine organisms. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. The Use of the Schizonticidal Agent Quinine Sulfate to Prevent Pond Crashes for Algal-Biofuel Production

    Science.gov (United States)

    Xu, Chunyan; Wu, Kangyan; Van Ginkel, Steve W.; Igou, Thomas; Lee, Hwa Jong; Bhargava, Aditya; Johnston, Rachel; Snell, Terry; Chen, Yongsheng

    2015-01-01

    Algal biofuels are investigated as a promising alternative to petroleum fuel sources to satisfy transportation demand. Despite the high growth rate of algae, predation by rotifers, ciliates, golden algae, and other predators will cause an algae in open ponds to crash. In this study, Chlorella kessleri was used as a model alga and the freshwater rotifer, Brachionus calyciflorus, as a model predator. The goal of this study was to test the selective toxicity of the chemical, quinine sulfate (QS), on both the alga and the rotifer in order to fully inhibit the rotifer while minimizing its impact on algal growth. The QS LC50 for B. calyciflorus was 17 µM while C. kessleri growth was not inhibited at concentrations biodiesel in one year are estimated to be $0.04/gallon or ~1% of Bioenergy Technologies Office’s (BETO) projected cost of $5/gge (gallon gasoline equivalent). This provides algae farmers an important tool to manage grazing predators in algae mass cultures and avoid pond crashes. PMID:26593899

  3. The Use of the Schizonticidal Agent Quinine Sulfate to Prevent Pond Crashes for Algal-Biofuel Production

    Directory of Open Access Journals (Sweden)

    Chunyan Xu

    2015-11-01

    Full Text Available Algal biofuels are investigated as a promising alternative to petroleum fuel sources to satisfy transportation demand. Despite the high growth rate of algae, predation by rotifers, ciliates, golden algae, and other predators will cause an algae in open ponds to crash. In this study, Chlorella kessleri was used as a model alga and the freshwater rotifer, Brachionus calyciflorus, as a model predator. The goal of this study was to test the selective toxicity of the chemical, quinine sulfate (QS, on both the alga and the rotifer in order to fully inhibit the rotifer while minimizing its impact on algal growth. The QS LC50 for B. calyciflorus was 17 µM while C. kessleri growth was not inhibited at concentrations <25 µM. In co-culture, complete inhibition of rotifers was observed when the QS concentration was 7.7 µM, while algal growth was not affected. QS applications to produce 1 million gallons of biodiesel in one year are estimated to be $0.04/gallon or ~1% of Bioenergy Technologies Office’s (BETO projected cost of $5/gge (gallon gasoline equivalent. This provides algae farmers an important tool to manage grazing predators in algae mass cultures and avoid pond crashes.

  4. The ghost of herbivory past: slow defence relaxation in the chlorophyte Scenedesmus obliquus

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    Jacobus VIJVERBERG

    2009-08-01

    Full Text Available The freshwater chlorophyte Scenedesmus obliquus (Turpin Kützing produces colonies as an inducible defence against herbivores. We investigated the dynamics of Scenedesmus colony formation and disintegration in response to the density of the herbivorous rotifer Brachionus calyciflorus in large-scale mesocosms. Additional bioassays were performed to investigate Scenedesmus colony disintegration under different light regimes. In the mesocosm experiment, colony formation took place rapidly, but relaxation towards the initial size took relatively long (>10 d after cessation of herbivory. In the bioassays, in the absence of infochemicals, colonies disintegrated almost immediately in the dark (1-1.5 d, within 4 d under a photoperiod of 16:8 (L:D and between 8 and 12 days under full light. Colony disintegration times in the mesocosm experiment were substantially longer as compared to treatments with the same photoperiod (L:D 16:8 in the bioassays. So after a peak of herbivory, the 'ghost of herbivory past', i.e. the remaining infochemicals, may continue to induce colony formation, causing an additional lengthening of colony disintegration times and associated fitness costs (higher sedimentation loss rates. This indicates that costs of colony formation are not only important during the induction phase, but may be even more important during the relaxation phase. We compared these sedimentation costs to the costs of herbivory for differently sized Scenedesmus, and found a clear trade-off pattern for these costs.

  5. Captive propagation, reproductive biology, and early life history of the Diamond Darter (Crystallaria cincotta)

    Science.gov (United States)

    Ruble, Crystal L.; Rakes, Patrick L.; Shute, John R.; Welsh, Stuart A.

    2014-01-01

    Reproductive biology and early life history data are critical for the conservation and management of rare fishes. During 2008–2012 a captive propagation study was conducted on the Diamond Darter, Crystallaria cincotta, a rare species with a single extant population in the lower Elk River, West Virginia. Water temperatures during spawning ranged from 11.1–23.3 C. Females and males spawned with quick vibrations, burying eggs in fine sand in relatively swift clean depositional areas. Egg size was 1.8–1.9 mm, and embryos developed within 7 to 11 d. Diamond Darters were 6.7–7.2 mm total length (TL) at hatch. Larvae ranged from 9.0–11.0 mm TL following a 5–10 d period of yolk sac absorption. Larvae had relatively large mouth gapes and teeth and were provided brine shrimp Artemia sp., Ceriodaphnia dubia neonates, marine Brachionus rotifers, and powdered foods (50–400 µm) but did not appear to feed in captivity, except for one observation of larval cannibalization. Larvae survived for a maximum of 10 d. To increase larval survival and reduce the possibility of cannibalism, other alternative food sources are needed during captive propagation.

  6. Transcriptome data reveal Syndermatan relationships and suggest the evolution of endoparasitism in Acanthocephala via an epizoic stage.

    Science.gov (United States)

    Wey-Fabrizius, Alexandra R; Herlyn, Holger; Rieger, Benjamin; Rosenkranz, David; Witek, Alexander; Welch, David B Mark; Ebersberger, Ingo; Hankeln, Thomas

    2014-01-01

    The taxon Syndermata comprises the biologically interesting wheel animals ("Rotifera": Bdelloidea + Monogononta + Seisonidea) and thorny-headed worms (Acanthocephala), and is central for testing superordinate phylogenetic hypotheses (Platyzoa, Gnathifera) in the metazoan tree of life. Recent analyses of syndermatan phylogeny suggested paraphyly of Eurotatoria (free-living bdelloids and monogononts) with respect to endoparasitic acanthocephalans. Data of epizoic seisonids, however, were absent, which may have affected the branching order within the syndermatan clade. Moreover, the position of Seisonidea within Syndermata should help in understanding the evolution of acanthocephalan endoparasitism. Here, we report the first phylogenomic analysis that includes all four higher-ranked groups of Syndermata. The analyzed data sets comprise new transcriptome data for Seison spec. (Seisonidea), Brachionus manjavacas (Monogononta), Adineta vaga (Bdelloidea), and Paratenuisentis ambiguus (Acanthocephala). Maximum likelihood and Bayesian trees for a total of 19 metazoan species were reconstructed from up to 410 functionally diverse proteins. The results unanimously place Monogononta basally within Syndermata, and Bdelloidea appear as the sister group to a clade comprising epizoic Seisonidea and endoparasitic Acanthocephala. Our results support monophyly of Syndermata, Hemirotifera (Bdelloidea + Seisonidea + Acanthocephala), and Pararotatoria (Seisonidea + Acanthocephala), rejecting monophyly of traditional Rotifera and Eurotatoria. This serves as an indication that early acanthocephalans lived epizoically or as ectoparasites on arthropods, before their complex lifecycle with arthropod intermediate and vertebrate definite hosts evolved.

  7. Extreme levels of hidden diversity in microscopic animals (Rotifera) revealed by DNA taxonomy.

    Science.gov (United States)

    Fontaneto, Diego; Kaya, Murat; Herniou, Elisabeth A; Barraclough, Timothy G

    2009-10-01

    Knowledge and estimates of species richness at all scales are biased both by our understanding of the evolutionary processes shaping diversity and by the methods used to delineate the basic units of diversity. DNA taxonomy shows that diversity may be underestimated by traditional taxonomy, especially for microscopic animals. The effects of such hidden diversity are usually overlooked in ecological studies. Here, we estimate hidden diversity in bdelloid rotifers, a group of microscopic animals. We analyse cryptic diversity using a coalescent approach to infer taxonomical units from phylogenetic trees. Cryptic diversity was measured for eight traditional species of bdelloid rotifers and the results compared to that of the monogonont rotifer Brachionus plicatilis species complex, which is well studied and for which cross-mating experiments have been performed to explicitly define some of the species boundaries. A taxonomic inflation of up to 34 potential cryptic taxa was found in bdelloids. Cryptic taxa within each traditional species may be spatially isolated, but do not have narrower ecological niches. The species deemed as generalists exhibit the highest cryptic diversity. Cryptic diversity based on molecular characterization is commonly found in animals; nevertheless, the amount of cryptic diversity in bdelloids is much higher than in other groups analysed so far, maybe because of their peculiar parthenogenetic reproduction, other than microscopic size. We discuss this hypothesis in the light of the available empirical evidence from other groups of microscopic invertebrates, such as tardigrades and mites, which share size, habitat heterogeneity, potential for dispersal, and/or parthenogenetic reproduction.

  8. Transcriptome data reveal Syndermatan relationships and suggest the evolution of endoparasitism in Acanthocephala via an epizoic stage.

    Directory of Open Access Journals (Sweden)

    Alexandra R Wey-Fabrizius

    Full Text Available The taxon Syndermata comprises the biologically interesting wheel animals ("Rotifera": Bdelloidea + Monogononta + Seisonidea and thorny-headed worms (Acanthocephala, and is central for testing superordinate phylogenetic hypotheses (Platyzoa, Gnathifera in the metazoan tree of life. Recent analyses of syndermatan phylogeny suggested paraphyly of Eurotatoria (free-living bdelloids and monogononts with respect to endoparasitic acanthocephalans. Data of epizoic seisonids, however, were absent, which may have affected the branching order within the syndermatan clade. Moreover, the position of Seisonidea within Syndermata should help in understanding the evolution of acanthocephalan endoparasitism. Here, we report the first phylogenomic analysis that includes all four higher-ranked groups of Syndermata. The analyzed data sets comprise new transcriptome data for Seison spec. (Seisonidea, Brachionus manjavacas (Monogononta, Adineta vaga (Bdelloidea, and Paratenuisentis ambiguus (Acanthocephala. Maximum likelihood and Bayesian trees for a total of 19 metazoan species were reconstructed from up to 410 functionally diverse proteins. The results unanimously place Monogononta basally within Syndermata, and Bdelloidea appear as the sister group to a clade comprising epizoic Seisonidea and endoparasitic Acanthocephala. Our results support monophyly of Syndermata, Hemirotifera (Bdelloidea + Seisonidea + Acanthocephala, and Pararotatoria (Seisonidea + Acanthocephala, rejecting monophyly of traditional Rotifera and Eurotatoria. This serves as an indication that early acanthocephalans lived epizoically or as ectoparasites on arthropods, before their complex lifecycle with arthropod intermediate and vertebrate definite hosts evolved.

  9. Experimental studies on the larval development of the shrimps Crangon crangon and C. allmanni

    Science.gov (United States)

    Criales, M. M.; Anger, K.

    1986-09-01

    Larvae of the shrimps Crangon crangon L. and C. allmanni Kinahan were reared in the laboratory from hatching through metamorphosis. Effects of rearing methods (larval density, application of streptomycin, food) and of salinity on larval development were tested only in C. crangon, influence of temperature was studied in both species. Best results were obtained when larvae were reared individually, with a mixture of Artemia sp. and the rotifer Brachionus plicatilis as food. Streptomycin had partly negative effects and was thus not adopted for standard rearing techniques. All factors tested in this study influenced not only the rates of larval survival and moulting, but also morphogenesis. In both species, in particular in C. crangon, a high degree of variability in larval morphology and in developmental pathways was observed. Unsuitable conditions, e.g. crowding in mass culture, application of antibiotics, unsuitable food (rotifers, phytoplankton), extreme temperatures and salinities, tend to increase the number of larval instars and of morphological forms. The frequency of moulting is controlled mainly by temperature. Regression equations describing the relations between the durations of larval instars and temperature are given for both Crangon species. The number of moults is a linear function of larval age and a power function of temperature. There is high variation in growth (measured as carapace length), moulting frequency, morphogenesis, and survival among hatches originating from different females. The interrelations between these different measures of larval development in shrimps and prawns are discussed.

  10. Rotifer assemblages (Rotifera: Eurotatoria of the floodplain lakes of Majuli River Island, the Brahmaputra river basin, northeast India

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    Bhushan Kumar Sharma

    2014-12-01

    Full Text Available Our plankton and semi-plankton collections from twelve floodplain lakes (beels of Majuli River Island, Upper Assam reveal 124 rotifer species (32 genera and 17 families; these merit biodiversity value as ~52.0% and ~30.0% of species, ~68.0 and ~45.0% of  genera and ~74.0 and ~65.0% of the families of the Phylum known from northeast India (NEI and India, respectively. Two species are new to India with Trichocerca uncinata as new record to the Oriental region.  Eleven species are new to the study area and we provide an updated list (144 species for following meta-analyses of Majuli Rotifera. Biogeographically important elements include one Australasian, four Oriental, four Palaeotropical and one cosmo (sub tropical species while several species are of regional distribution interest. The rotifer fauna is predominantly tropical and Lecanidae > Lepadellidae collectively include ~53.0% species but it records paucity of Brachionus species. Individual beels record total richness of 60-100 (77 ± 12 species, monthly richness between 24 ± 7-34 ± 7 species and maximum up to 54 species/sample. The results are characterized by high community similarities (59.7-90.4% vide Sørensen’s index, more rotifer homogeneity amongst beels, lack of any pattern of temporal richness variations and much limited influence of abiotic parameters.

  11. Sediment quality in the Atlantic coast of Spain.

    Science.gov (United States)

    Riba, Inmaculada; Casado-Martínez, Carmen; Forja, Jesús M; DelValls, Angel

    2004-02-01

    Sediments from the Atlantic coast of Spain have been studied to evaluate environmental quality by using an integrated approach including chemical and toxicological data. Sediment samples were collected in four littoral ecosystems located in Spain, Bay of Cádiz, Guadalquivir River estuary, Ría of Huelva, and Ría of Coruña. To characterize the sediments, organic carbon, granulometric content, total sulfide, eight trace metals (Hg, Cd, Pb, Cu, Zn, As, Ni, and Cr), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) were measured. The toxicity of sediments was assessed with the amphipod Ampelisca brevicornis, the clam Ruditapes philippinarum, juveniles of the fish Solea senegalensis, populations of the estuarine rotifer Brachionus plicatilis, and populations of the bacterium Vibrio fischeri (Microtox). The results obtained show that in general, stations located in the Ría of Huelva were associated with heavy metal contamination and with the highest toxicity. Only chronic toxicity tests were capable of identifying the effects associated with PCB concentrations. The sediment quality guidelines calculated by means of a multivariate analysis approach for contaminants not associated with biological effects (mg/kg) are Hg, 0.54; Cd, 0.51; Pb, 260; Cu, 209; Zn, 513; As, 27.4; and total PCBs, 0.05.

  12. Effects of wood preservative leachates from docks

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, P.H.; Van Dolah, R.F.; Bobo, M.Y.; Mathews, T.D. [South Carolina Marine Resources Research Inst., Charleston, SC (United States)

    1994-12-31

    Recent evidence indicates that the wood preservative commonly used in dock pilings (chromated copper arsenate or CCA) is highly toxic to several estuarine organisms in laboratory experiments. Increasing demand for residential docks prompted a field study intended to complement these earlier laboratory investigations. Objectives of the study were to: (1) examine concentrations of Cu, Cr, and As in sediments and oysters from intertidal locations in several creeks with and without high densities of docks; (2) examine the bioaccumulation of wood preservative leachates by laboratory-reared oysters transferred to field sites near and distant from newly constructed docks; and (3) investigate the acute toxicity of wood preservative leachates for several species of estuarine fishes and invertebrates exposed to these compounds in the field. Preliminary results indicate that sediment concentrations of all three metals were well below ER-L levels reported by Long and Morgan at all but one dock site. In an ancillary study, 24h LC{sub 50} bioassays were performed using rotifers (Brachionus plicatilis) which were exposed to pore water from sediments in creeks with and without docks. Toxicities of bulk sediments from the same sites were examined using Microtox which measures decreases in bioluminescence of marine bacteria (Photobacterium phosphoreum) as a function of sediment concentration. Neither the rotifer nor the Microtox bioassays showed any significant differences in toxicity between creeks with and without docks.

  13. Effects of predation by Hydra (Cnidaria on cladocerans (Crustacea: Cladocera

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    Ligia Rivera-De la Parra

    2016-03-01

    Full Text Available Planktonic cladocerans have evolved different strategies to avoid predation from vertebrates; these include changes in morphology, behavior, physiology, and/or life-history traits. However, littoral cladocerans are better adapted to avoid invertebrate predation particularly from insect larvae by evolving morphological and physiological adaptations. Nevertheless, this has not been proven for some littoral predators such as Hydra. In this study, we provide quantitative data on how Hydra affects its zooplankton prey. We studied the predation behavior on Alona glabra, Ceridodaphnia dubia, Daphnia pulex, Daphnia cf. mendotae, Diaphanosoma birgei, Macrothrix triserialis, Moina macrocopa, Pleuroxus aduncus, Scapholeberis kingi, Simocephalus vetulus, Elaphoidella grandidieri, Brachionus rubens and Euchlanis dilatata. We also tested the indirect effect of allelochemicals from Hydra on the demography of Daphnia cf. mendotae. Littoral cladocerans are specially adapted to resist nematocyst injection and discharge of toxic substances from Hydra. A significant decrease in the population growth rate from 0.21 to 0.125 d-1 was observed at densities of 2 ind. ml-1. The role of carapace thickness as an adaptive strategy of littoral cladocerans against Hydra predation is discussed.

  14. Use of solar advanced oxidation processes for wastewater treatment: Follow-up on degradation products, acute toxicity, genotoxicity and estrogenicity.

    Science.gov (United States)

    Brienza, M; Mahdi Ahmed, M; Escande, A; Plantard, G; Scrano, L; Chiron, S; Bufo, S A; Goetz, V

    2016-04-01

    Wastewater tertiary treatment by advanced oxidation processes is thought to produce a treated effluent with lower toxicity than the initial influent. Here we performed tertiary treatment of a secondary effluent collected from a Waste Water Treatment Plant via homogeneous (solar/HSO5(-)/Fe(2+)) and heterogeneous (solar/TiO2) solar advanced oxidation aiming at the assessment of their effectiveness in terms of contaminants' and toxicity abatement in a plain solar reactor. A total of 53 organic contaminants were qualitatively identified by liquid chromatography coupled to high-resolution mass spectrometry after solid phase extraction. Solar advanced oxidation totally or partially removed the major part of contaminants detected within 4.5 h. Standard toxicity tests were performed using Vibrio fischeri, Daphnia magna, Pseudokirchneriella subcapitata and Brachionus calyciflorus organisms to evaluate acute and chronic toxicity in the secondary or tertiary effluents, and the EC50% was calculated. Estrogenic and genotoxic tests were carried out in an attempt to obtain an even sharper evaluation of potential hazardous effects due to micropollutants or their degradation by-products in wastewater. Genotoxic effects were not detected in effluent before or after treatment. However, we observed relevant estrogenic activity due to the high sensitivity of the HELN ERα cell line. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Higher rates of sex evolve in spatially heterogeneous environments.

    Science.gov (United States)

    Becks, Lutz; Agrawal, Aneil F

    2010-11-04

    The evolution and maintenance of sexual reproduction has puzzled biologists for decades. Although this field is rich in hypotheses, experimental evidence is scarce. Some important experiments have demonstrated differences in evolutionary rates between sexual and asexual populations; other experiments have documented evolutionary changes in phenomena related to genetic mixing, such as recombination and selfing. However, direct experiments of the evolution of sex within populations are extremely rare (but see ref. 12). Here we use the rotifer, Brachionus calyciflorus, which is capable of both sexual and asexual reproduction, to test recent theory predicting that there is more opportunity for sex to evolve in spatially heterogeneous environments. Replicated experimental populations of rotifers were maintained in homogeneous environments, composed of either high- or low-quality food habitats, or in heterogeneous environments that consisted of a mix of the two habitats. For populations maintained in either type of homogeneous environment, the rate of sex evolves rapidly towards zero. In contrast, higher rates of sex evolve in populations experiencing spatially heterogeneous environments. The data indicate that the higher level of sex observed under heterogeneity is not due to sex being less costly or selection against sex being less efficient; rather sex is sufficiently advantageous in heterogeneous environments to overwhelm its inherent costs. Counter to some alternative theories for the evolution of sex, there is no evidence that genetic drift plays any part in the evolution of sex in these populations.

  16. Biodiversity of freshwater rotifers (Rotifera: Eurotatoria of Mizoram, Northeast India: composition, new records and interesting features

    Directory of Open Access Journals (Sweden)

    Bhushan Kumar Sharma

    2015-10-01

    Full Text Available The plankton and semi-plankton samples examined from Mizoram state of northeast India (NEI revealed speciose and diverse Rotifera assemblage including a total richness (S of 162 species belonging to 19 families and 35 genera. The reports of six species new to India, four species new to NEI and 76 new records to Mizoram merit biodiversity interest. The occurrence of one Australasian, one Oriental, seven Paleotropical, one Holarctic, one cosmo (sub tropical and five other interesting species imparts biogeographical value while several species indicate regional distribution importance. Lecanidae > Lepadellidae > Brachionidae > Trichocercidae collectively comprised 69.7% of total richness (S. Lecane > Lepadella > Trichocerca are diverse genera (~52.0% of S while Brachionus spp. (~8.0% deserve cautious mention. The rotifer diversity pattern is predominantly ‘tropical’ with a large component of cosmopolitans (~71.0% of S while tropicopolitan and pantropical species contributed ~16.0%. This study indicated high richness of the littoral-periphytonic and relative paucity of planktonic taxa. Analysis of periphytic, sessile, colonial and benthic taxa, and of cryptic diversity in certain species-groups merit attention for further biodiversity update and we estimate occurrence of 250+ rotifer species in Mizoram.

  17. Rich rotifer assemblage (Rotifera: Eurotatoria of a sub-tropical wetland of Meghalaya, northeast India: ecosystem diversity and interesting features

    Directory of Open Access Journals (Sweden)

    Bhushan Kumar Sharma

    2016-07-01

    Full Text Available A total of 90 species, belonging to 29 genera and 15 families, observed from an urban wetland of Meghalaya is the species-rich Rotifera assemblage known till date from any sub-tropical ecosystem of the Indian sub-region. Total richness (S merits biodiversity value as ~56.0, ~ 38.0 and ~23.0 % of the species recorded from Meghalaya, northeast India (NEI and India, respectively while several rotifers of global and regional importance impart biogeographic interest. One species is new to NEI and 19 species (including two unidentified are new to Meghalaya; this study resulted in an earlier report of five and two new records from India and NEI, respectively. The diverse Lecanidae > Lepadellidae together comprising ~ 57.0 % of S; largely littoral periphytonic nature of taxa; and distinct paucity of the Brachionidae and lack of Brachionus are notable features. The speciose Lecane, high richness of cosmopolitans and occurrence of several tropicopolitan and pantropical species impart broadly ‘tropical’ character to the fauna. With low monthly richness and low community similarities, our results affirm heterogeneity of rotifer species composition; the richness is positively influenced only by water temperature.

  18. Impact of chromium and aluminium pollution on the diversity of zooplankton: a case study in the Chimaliapan wetland (Ramsar site) (Lerma basin, Mexico).

    Science.gov (United States)

    García-García, Gerardo; Nandini, S; Sarma, S S S; Martínez-Jerónimo, Fernando; Jiménez-Contreras, Jorge

    2012-01-01

    Biological monitoring and the use of biotic indices are important in evaluating the health of aquatic systems. However, zooplankton are rarely included in biomonitoring protocols. We conducted a one-year study (March 2008-February 2009) at two sites from the Chimaliapan wetland, with concentrations of aluminium (Al) and chromium (Cr) above and within the permissible limits, respectively. Metals in the sediment and water were analyzed from three locations per site every two months. In addition to analyses of the abundance and diversity of rotifers, cladocerans and copepods, we sampled 11 physicochemical variables in the water and six from the sediments. The metal concentration in the polluted site (significantly above the permissible limits) ranged between 7266-8174 mg Kg(-1) of Al and 14.6-18.3 mg Kg(-1) of Cr. We found 92 species of rotifers, cladocerans and copepods. The Brillouin index for both sites ranged from 3.9-5.4, the Shannon-Wiener index from 4.2-5.5 while the Brachionus-Trichocerca ratio ranged between 1.0 and 1.7. The Wetland Zooplankton Index was significantly different among the sites; 2.63 at site 1 and 2.13 at site 2. The saprobic index was 3.2 for both sites. Data analyses using multifactorial techniques suggested that zooplankton can be used to evaluate the impact of the metals aforementioned, since these organisms are generally more sensitive than other groups and also have a high ecological relevance.

  19. Réflexions sur les rotifères en tant qu'indicateurs biologiques

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    POURRIOT R.

    1976-01-01

    Full Text Available Quelques espèces de Rotifères fournissent un bon exemple d'indicateurs écologiques pour un facteur limitant : Synchaeta lakowitziana, Conochitoides natans, Notholca spp (température, Brachionus plicatilis (salinité. Le système d'indexation des espèces à la qualité des eaux est discuté. Les espèces strictement édaphiques (non aquatiques, les espèces rares appartenant à des genres où la variabilité est grande et les espèces euryoecques, peu caractéristiques, devraient être exclues des listes d'indicateurs établies par SLADECEK (1973, car elles ne facilitent pas l'application de ce système. Il s'avère nécessaire d'améliorer le poids indicatif et la valeur de saprobité des espèces, de ne conserver que les plus caractéristiques par leur constance et leur fidélité. Il serait, de plus, intéressant de se référer à des index plus dynamiques que statiques.

  20. Evaluation of toxicity and removal of color in textile effluent treated with electron beam; Avaliacao da toxicidade e remocao da cor de um efluente textil tratado com feixe de eletrons

    Energy Technology Data Exchange (ETDEWEB)

    Morais, Aline Viana de

    2015-07-01

    The textile industry is among the main activities Brazil, being relevant in number of jobs, quantity and diversity of products and mainly by the volume of water used in industrial processes and effluent generation. These effluents are complex mixtures which are characterized by the presence of dyes, surfactants, metal sequestering agents, salts and other potentially toxic chemicals for the aquatic biota. Considering the lack of adequate waste management to these treatments, new technologies are essential in highlighting the advanced oxidation processes such as ionizing radiation electron beam. This study includes the preparation of a standard textile effluent chemical laboratory and its treatment by electron beam from electron accelerator in order to reduce the toxicity and intense staining resulting from Cl. Blue 222 dye. The treatment caused a reduction in toxicity to exposed organisms with 34.55% efficiency for the Daphnia similis micro crustacean and 47.83% for Brachionus plicatilis rotifer at a dose of 2.5 kGy. The Vibrio fischeri bacteria obtained better results after treatment with a dose of 5 kGy showing 57.29% efficiency. Color reduction was greater than 90% at a dose of 2.5 kGy. This experiment has also carried out some preliminary tests on the sensitivity of the D. similis and V. fischeri organisms to exposure of some of the products used in this bleaching and dyeing and two water reuse simulations in new textile processing after the treating the effluent with electron beam. (author)

  1. Transcriptome Data Reveal Syndermatan Relationships and Suggest the Evolution of Endoparasitism in Acanthocephala via an Epizoic Stage

    Science.gov (United States)

    Rieger, Benjamin; Rosenkranz, David; Witek, Alexander; Welch, David B. Mark; Ebersberger, Ingo; Hankeln, Thomas

    2014-01-01

    The taxon Syndermata comprises the biologically interesting wheel animals (“Rotifera”: Bdelloidea + Monogononta + Seisonidea) and thorny-headed worms (Acanthocephala), and is central for testing superordinate phylogenetic hypotheses (Platyzoa, Gnathifera) in the metazoan tree of life. Recent analyses of syndermatan phylogeny suggested paraphyly of Eurotatoria (free-living bdelloids and monogononts) with respect to endoparasitic acanthocephalans. Data of epizoic seisonids, however, were absent, which may have affected the branching order within the syndermatan clade. Moreover, the position of Seisonidea within Syndermata should help in understanding the evolution of acanthocephalan endoparasitism. Here, we report the first phylogenomic analysis that includes all four higher-ranked groups of Syndermata. The analyzed data sets comprise new transcriptome data for Seison spec. (Seisonidea), Brachionus manjavacas (Monogononta), Adineta vaga (Bdelloidea), and Paratenuisentis ambiguus (Acanthocephala). Maximum likelihood and Bayesian trees for a total of 19 metazoan species were reconstructed from up to 410 functionally diverse proteins. The results unanimously place Monogononta basally within Syndermata, and Bdelloidea appear as the sister group to a clade comprising epizoic Seisonidea and endoparasitic Acanthocephala. Our results support monophyly of Syndermata, Hemirotifera (Bdelloidea + Seisonidea + Acanthocephala), and Pararotatoria (Seisonidea + Acanthocephala), rejecting monophyly of traditional Rotifera and Eurotatoria. This serves as an indication that early acanthocephalans lived epizoically or as ectoparasites on arthropods, before their complex lifecycle with arthropod intermediate and vertebrate definite hosts evolved. PMID:24520404

  2. Inclusion of copepod Acartia tonsa nauplii in the feeding of Centropomus undecimalis larvae increases stress resistance

    Directory of Open Access Journals (Sweden)

    Wanessa de Melo-Costa

    2015-09-01

    Full Text Available This research represents the first result of studies of the common snook Centropomus undecimalis larvae from broodstock matured in captivity in Brazil. The aim of this study was to evaluate if the inclusion of Acartia tonsa nauplii improves stress resistance of common snook larvae. The larvae were fed with: rotifers Brachionus plicatilis (10 to 15 mL-1; A. tonsa nauplii (0.25 to 0.5 mL-1 and rotifers (5 to 7.5 mL-1, and A. tonsa nauplii (0.12 to 0.25 mL-1. The average percentage of survival of the treatments was 11.9%. At 20 days of age, larvae were subjected to thermal stress. Subsequently, the stress resistance was evaluated. Common snook larvae fed B. plicatilis+A. tonsa reached a higher weight and length (7.5 ± 0.00 mg and 9.1 ± 0.23 mm, respectively and resisted more heat stress (87.4% than larvae fed other foods, indicating that the feed mixture is satisfactory as a starter diet for larvae of common snook. However, more research is needed to confirm these results.

  3. Evidence Supporting the Uptake and Genomic Incorporation of Environmental DNA in the “Ancient Asexual” Bdelloid Rotifer Philodina roseola

    Directory of Open Access Journals (Sweden)

    Olaf R. P. Bininda-Emonds

    2016-09-01

    Full Text Available Increasing evidence suggests that bdelloid rotifers regularly undergo horizontal gene transfer, apparently as a surrogate mechanism of genetic exchange in the absence of true sexual reproduction, in part because of their ability to withstand desiccation. We provide empirical support for this latter hypothesis using the bdelloid Philodina roseola, which we demonstrate to readily internalize environmental DNA in contrast to a representative monogonont rotifer (Brachionus rubens, which, like other monogononts, is facultative sexual and cannot withstand desiccation. In addition, environmental DNA that was more similar to the host DNA was retained more often and for a longer period of time. Indirect evidence (increased variance in the reproductive output of the untreated F1 generation suggests that environmental DNA can be incorporated into the genome during desiccation and is thus heritable. Our observed fitness effects agree with sexual theory and also occurred when the animals were desiccated in groups (thereby acting as DNA donors, but not individually, indicating the mechanism could occur in nature. Thus, although DNA uptake and its genomic incorporation appears proximally related to anhydrobiosis in bdelloids, it might also facilitate accidental genetic exchange with closely related taxa, thereby maintaining higher levels of genetic diversity than is otherwise expected for this group of “ancient asexuals”.

  4. Temporal and Spatial Dynamics of Planktonic Rotifers in the Elbe Estuary during Spring

    Science.gov (United States)

    Holst, H.; Zimmermann, H.; Kausch, H.; Koste, W.

    1998-09-01

    The spatial and temporal distribution of planktonic rotifers in the Elbe Estuary, Germany, was investigated at weekly intervals from March to July, 1995. Samples were taken at a fixed site in the Hahnöfer Nebenelbe, and the main channel was surveyed four times at eight stations from Hamburg to the upstream limits of the brackish-water zone. Abiotic and biotic parameters were determined and correlated with rotifer abundance to gain information about the forces that structure the rotifer community in this dynamic environment. A maximum density of 2048 ind. l -1was observed at the beginning of June. More than 70 rotifer species were identified during the whole period, but only a few of them appeared at significant densities. The predominant species were Keratella cochlearis, which accounted for over 32% of the total abundance, Keratella quadrata, Brachionus calyciflorusand species of the genera Synchaetaand Polyarthra. At the end of July Synchaeta bicornisappeared at the low density of 23 ind. l -1at the station farthest downstream. Except for this typical brackish-water species, all rotifers encountered belonged to freshwater taxa, which decreased in abundance rather rapidly toward the river mouth. From March to the middle of June, rotifers grazed predominantly on heterotrophic components of the microbial food-web, such as planktonic and aggregate-associated bacteria, detritus and heterotrophic flagellates. Toward the end of June, the chlorophyll aconcentration increased sharply, and a new rotifer community established itself, feeding mainly on autotrophic organisms in the Elbe Estuary.

  5. The Trophic Contributions of Rotifers in Tidal Freshwater and Estuarine Habitats

    Science.gov (United States)

    Park, G. S.; Marshall, H. G.

    2000-12-01

    Distribution patterns and trophic contributions of rotifers from freshwater through polyhaline estuarine waters were examined in the southern Chesapeake Bay and its major tributaries for a two-year period. Trichocerca marina and Synchaeta spp. were the major taxa in abundance, followed by Polyarthra vulgaris, Keratella cochlearis and Brachionus spp. There was a significant negative correlation between salinity and rotifer density, biomass, and number of species. Rotifers were a component of the microzooplankton biomass during specific periods and at particular sites, dominating summer assemblages in tidal freshwater and river-estuary transition sites, plus the winter communities in estuarine waters. This observation indicates that rotifers may play an important trophic role by seasonally replacing metazoan nauplii as a biomass source in both tidal freshwater and estuarine ecosystems. The annual contribution of rotifers to the total microzooplankton biomass exclusive of heterotrophic dinoflagellates was brief but intensive, achieving over 50% of annual biomass during a 2-3 month period. Despite the small annual mean contribution of rotifers to the total microzooplankton biomass, rotifers may have a limited, but significant impact on the trophic dynamics of the zooplankton community in Chesapeake Bay and its major tidal tributaries.

  6. Prey-predator dynamics in rotifers: density-dependent consequences of spatial heterogeneity due to surface attachment.

    Science.gov (United States)

    Vadstein, Olav; Olsen, Lasse M; Andersen, Tom

    2012-08-01

    Classical models of prey-predator interactions assume that per capita prey consumption is dependent on prey density alone and that prey consumption (functional response) and consumer proliferation (numerical response) operate on the same timescales and without time lags. Several modifications have been proposed for resolving this timescale discrepancy, including variants where the functional response depends on both prey and predator densities. A microcosm system with the rotifer Brachionus 'Nevada' feeding on the prasinophyte Tetraselmis sp. showed significant (P rotifers, which can result in a predator-dependent functional response. We also show that partitioning between the attached and free-swimming habitats was fast compared to the timescale of the numerical response. When attached to surfaces, rotifers maximized net energy gain by avoiding the high cost of swimming and by increased food capture due to reduced viscous drag. A mathematical model with prey-dependent functional response and wall-attached and free-swimming fractions of the population describes our data adequately. We discuss the implications of this finding for extrapolating microcosm experiments to systems with other surface-to-volume ratios, and to what extent our findings may apply to other popular model organisms for prey-predator interaction.

  7. Rotifers (Rotifera: Eurotatoria from floodplain lakes of the Dibru Saikhowa Biosphere Reserve, upper Assam, northeast India: ecosystem diversity and biogeography

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    Bhushan Kumar Sharma

    2017-05-01

    Full Text Available This study aims to assess ecosystem diversity of Rotifera of the floodplain lakes (beels of the Brahmaputra river basin with reference to faunal diversity of the taxon in wetlands of conservation areas of India. We observed 141 rotifer species, belonging to 31 genera and 17 families, from three beels of the Dibru-Saikhowa Biosphere Reserve (DSBR of Assam, northeast India (NEI with high total richness (117±2 species in individual beels. One, two and three species are new to the Oriental region, India and Assam state, respectively and 21 species are globally interesting. The diverse Lecanidae > Lepadellidae > Trichocercidae; the paucity and scarceness of Brachionidae and Brachionus spp. in particular; and rare nature of Keratella, Filinia, Asplanchna, Polyarthra, and Conochilus are salient. The monthly richness and community similarities affirmed heterogeneity in species composition in individual beels while this study exhibited overall rotifer homogeneity amongst beels. The richness followed monthly oscillations in the three beels and lacked significant variations amongst beels. The peak richness of 76 species during summer (May, 2014 from No. 11 beel is one of the richest rotifer assemblages known in single date collection from an aquatic ecosystem of South Asia. Our results explained little influence of individual abiotic factors while canonical correspondence analysis endorsed high cumulative influence of 17 abiotic factors on richness in all beels.

  8. Zooplankton-based assessment of the trophic state of a tropical forest river in Nigeria

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    Imoobe T.O.T.

    2009-01-01

    Full Text Available In this study, we explore the usefulness of zooplankton as a tool for assessing the trophic status of a Nigerian forest river. The river was sampled monthly and investigated for water physico-chemistry and zooplankton community structure using basic statistical measurement of diversity indices to characterize the zooplankton fauna. The trophic sta­tus of the river evaluated from its physico-chemical parameters indicates that the river is oligotrophic. The zooplankton composition was typical of a tropical freshwater river, with a total of 40 species, made up of 16 rotifers, 12 cladocerans, and 12 copepods and their developing stages in the following order of dominance: Rotifera > Cladocera > Cyclopoida > Calanoida. There were strong correlations between the lake's trophic status and its zooplankton communities. The zoo­plankton community was dominated by numerous species of rotifers and crustaceans, which are typical of oligotrophic to mesotrophic systems, such species including Conochilus dossuarius and Synchaeta longipes. However, the most dominant zooplankton species in West African freshwater ecosystems, viz., Keratella tropica, Keratella quadrata, Brachionus angularis, Trichocerca pusilla, Filinia longiseta, Pompholyx sulcata, and Proales sp., and others that are indicator species of high trophic levels, were not recorded in the river. The river is very clear and can be used for all manner of recreational activities.

  9. Evidence Supporting the Uptake and Genomic Incorporation of Environmental DNA in the “Ancient Asexual” Bdelloid Rotifer Philodina roseola

    Science.gov (United States)

    Bininda-Emonds, Olaf R. P.; Hinz, Claus; Ahlrichs, Wilko H.

    2016-01-01

    Increasing evidence suggests that bdelloid rotifers regularly undergo horizontal gene transfer, apparently as a surrogate mechanism of genetic exchange in the absence of true sexual reproduction, in part because of their ability to withstand desiccation. We provide empirical support for this latter hypothesis using the bdelloid Philodina roseola, which we demonstrate to readily internalize environmental DNA in contrast to a representative monogonont rotifer (Brachionus rubens), which, like other monogononts, is facultative sexual and cannot withstand desiccation. In addition, environmental DNA that was more similar to the host DNA was retained more often and for a longer period of time. Indirect evidence (increased variance in the reproductive output of the untreated F1 generation) suggests that environmental DNA can be incorporated into the genome during desiccation and is thus heritable. Our observed fitness effects agree with sexual theory and also occurred when the animals were desiccated in groups (thereby acting as DNA donors), but not individually, indicating the mechanism could occur in nature. Thus, although DNA uptake and its genomic incorporation appears proximally related to anhydrobiosis in bdelloids, it might also facilitate accidental genetic exchange with closely related taxa, thereby maintaining higher levels of genetic diversity than is otherwise expected for this group of “ancient asexuals”. PMID:27608044

  10. Two-dimensional micro-beam imaging of trace elements in a single plankton measured by a synchrotron radiation X-ray fluorescence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ezoe, Masako; Sasaki, Miho; Hokura, Akiko; Nakai, Izumi [Tokyo Univ. of Science, Faculty of Science, Tokyo (Japan); Terada, Yasuko [Japan Synchrotron Radiation Research Inst., Mikazuki, Hyogo (Japan); Yoshinaga, Tatsuki; Tukamoto, Katsumi [Tokyo Univ., Ocean Research Inst., Tokyo (Japan); Hagiwara, Atsushi [Nagasaki Univ., Graduate School of Science and Technology, Bunkyou, Nagasaki (Japan)

    2002-10-01

    Two-dimensional imaging and a quantitative analysis of trace elements in rotifer, Brachionus plicatilis, belonging to zooplankton, were carried out by a synchrotron radiation X-ray fluorescence analysis (SR-XRF). The XRF imaging revealed that female rotifers accumulated Fe and Zn in the digestive organ and Fe, Zn, Cu, and Ca in the sexual organs, while the Mn level was high in the head. From a quantitative analysis by inductively coupled plasma mass spectrometry (ICP-MS), we found that rotifers eat the chlorella and accumulate the above elements in the body. The result of quantitative analyses of Mn, Cu, and Zn by SR-XRF in a single sample is in fair agreement with the average values determined by ICP-MS analyses, which were obtained by measuring a large number of rotifers, digested by nitric acid. The present study has demonstrated that SR-XRF is an effective tool for the trace element analysis of a single individual of rotifer. (author)

  11. Sildenafil and tadalafil in simulated chlorination conditions: Ecotoxicity of drugs and their derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Temussi, Fabio; DellaGreca, Marina; Pistillo, Paola; Previtera, Lucio; Zarrelli, Armando [UdR Napoli 4 INCA, Dipartimento di Scienze Chimiche, Complesso Universitario di Monte Sant' Angelo, Università Federico II, Via Cintia, I-80126 Napoli (Italy); Criscuolo, Emma; Lavorgna, Margherita; Russo, Chiara [Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università di Napoli, Via Vivaldi 43, I-81100 Caserta (Italy); Isidori, Marina, E-mail: marina.isidori@unina2.it [Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università di Napoli, Via Vivaldi 43, I-81100 Caserta (Italy)

    2013-10-01

    Chlorination experiments on two drugs (sildenafil and tadalafil) were performed mimicking the conditions of a typical wastewater treatment process. The main transformation products were isolated by chromatographic techniques (Thin Layer Chromatography (TLC), Column Chromatography (CC), High Performance Liquid Chromatography (HPLC)) and fully characterized employing Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS) analyses. The environmental effects of the parent compounds and transformation products were evaluated using an overall toxicity approach that considered aquatic acute and chronic toxicity on Brachionus calyciflorus and Ceriodaphnia dubia as well as mutagenesis and genotoxicity on bacterial strains. The results revealed that both parent drugs did not show high acute and chronic toxicity for the organisms utilized in the bioassays while, chronic exposure to chlorine derivatives caused inhibition of growth population on rotifers and crustaceans. A mutagenic potential was found for all the compounds investigated. - Highlights: • Simulated disinfection process of pharmaceuticals was performed. • Toxicity and genotoxicity of sildenafil, tadalafil and their derivatives were evaluated. • Chlorine derivatives caused chronic toxicity on rotifers and crustaceans. • A mutagenic potential was found for all the compounds investigated.

  12. Multiple stressor effects of predation by rotifers and herbicide pollution on different Chlamydomonas strains and potential impacts on population dynamics.

    Science.gov (United States)

    Fischer, Beat B; Roffler, Severin; Eggen, Rik I L

    2012-12-01

    Environmental factors can interact with the effects of chemical pollutants on natural systems by inducing multiple stressor effects in individual organisms as well as by altering selection pressure on tolerant strains in heterogeneous populations. Predation is a stressful environmental factor relevant for many species. Therefore, the impact of predation by the rotifer Brachionus calyciflorus on tolerance of eight genetically different strains of the green alga Chlamydomonas reinhardtii to simultaneous exposure to each of the three herbicides (diuron, paraquat, and S-metolachlor) was tested. Interactions of combined stressors were analyzed based on the independent action model; additive, synergistic, and antagonistic effects of the combined exposure could be detected depending on the herbicide and strain tested. If cultures were acclimated (pre-exposed) to one stressor, tolerance to the second stressor could be increased. This indicates that physiological changes can induce cotolerance of predation-exposed algae to herbicides and of herbicide-treated algae to predation depending on the combination of stressors. The strain-specific differences in multiple stressor effects also changed the correlation of strains' tolerances to individual stressors determined during combined and single-stressor exposure. Changes in cotolerance to stressors affect selection pressure and population dynamics during long-term exposure. This shows that predation stress can have adverse effects on the toxicity of chemical pollutants to microalgae on the organism and population levels. Copyright © 2012 SETAC.

  13. Inventory and phylogenetic analysis of meiotic genes in monogonont rotifers.

    Science.gov (United States)

    Hanson, Sara J; Schurko, Andrew M; Hecox-Lea, Bette; Welch, David B Mark; Stelzer, Claus-Peter; Logsdon, John M

    2013-01-01

    A long-standing question in evolutionary biology is how sexual reproduction has persisted in eukaryotic lineages. As cyclical parthenogens, monogonont rotifers are a powerful model for examining this question, yet the molecular nature of sexual reproduction in this lineage is currently understudied. To examine genes involved in meiosis, we generated partial genome assemblies for 2 distantly related monogonont species, Brachionus calyciflorus and B. manjavacas. Here we present an inventory of 89 meiotic genes, of which 80 homologs were identified and annotated from these assemblies. Using phylogenetic analysis, we show that several meiotic genes have undergone relatively recent duplication events that appear to be specific to the monogonont lineage. Further, we compare the expression of "meiosis-specific" genes involved in recombination and all annotated copies of the cell cycle regulatory gene CDC20 between obligate parthenogenetic (OP) and cyclical parthenogenetic (CP) strains of B. calyciflorus. We show that "meiosis-specific" genes are expressed in both CP and OP strains, whereas the expression of one of the CDC20 genes is specific to cyclical parthenogenesis. The data presented here provide insights into mechanisms of cyclical parthenogenesis and establish expectations for studies of obligate asexual relatives of monogononts, the bdelloid rotifer lineage.

  14. Rotiferan Hox genes give new insights into the evolution of metazoan bodyplans.

    Science.gov (United States)

    Fröbius, Andreas C; Funch, Peter

    2017-04-04

    The phylum Rotifera consists of minuscule, nonsegmented animals with a unique body plan and an unresolved phylogenetic position. The presence of pharyngeal articulated jaws supports an inclusion in Gnathifera nested in the Spiralia. Comparison of Hox genes, involved in animal body plan patterning, can be used to infer phylogenetic relationships. Here, we report the expression of five Hox genes during embryogenesis of the rotifer Brachionus manjavacas and show how these genes define different functional components of the nervous system and not the usual bilaterian staggered expression along the anteroposterior axis. Sequence analysis revealed that the lox5-parapeptide, a key signature in lophotrochozoan and platyhelminthean Hox6/lox5 genes, is absent and replaced by different signatures in Rotifera and Chaetognatha, and that the MedPost gene, until now unique to Chaetognatha, is also present in rotifers. Collectively, our results support an inclusion of chaetognaths in gnathiferans and Gnathifera as sister group to the remaining spiralians.Rotifers are microscopic animals with an unusual, nonsegmented body plan consisting of a head, trunk and foot. Here, Fröbius and Funch investigate the role of Hox genes-which are widely used in animal body plan patterning-in rotifer embryogenesis and find non-canonical expression in the nervous system.

  15. Lifespan extension of rotifers by treatment with red algal extracts.

    Science.gov (United States)

    Snare, David J; Fields, Allison M; Snell, Terry W; Kubanek, Julia

    2013-12-01

    Aging results from an accumulation of damage to macromolecules inhibiting cellular replication, repair, and other necessary functions. Damage may be due to environmental stressors such as metal toxicity, oxidative stress caused by imperfections in electron transfer reactions, or other metabolic processes. In an effort to discover medical treatments that counteract this damage, we initiated a search for small molecule drugs from natural sources using life table experiments which, through their unbiased approach, present the opportunity to discover first-in-class molecules. We have identified marine red algae as a source of natural products that slow aging of the invertebrate rotifer Brachionus manjavacas. Rotifers are a promising model organism for life extension studies as they maintain a short, measurable lifespan while also having an extensive literature related to aging. Rotifer lifespan was increased 9-14% by exposure to three of a total of 200 screened red algal extracts. Bioassay guided fractionation led to semi-purified extracts composed primarily of lipids responsible for rotifer life extension. The life extending mixture from the red alga Acanthophora spicifera contained eicosanoic, octadecanoic, and hexadecanoic acids as well as several unidentified unsaturated fatty acids. The life extending effects of these small molecule mixtures are not a result of their direct antioxidant capacity; other unknown mechanisms of action are likely involved. An understanding of how these natural products interact with their molecular targets could lead to selective and effective treatments for slowing aging and reducing age related diseases. © 2013.

  16. Passive zooplankton community in different environments of a neotropical floodplain - doi: 10.4025/actascibiolsci.v34i4.11161

    Directory of Open Access Journals (Sweden)

    Claudia Costa Bonecker

    2012-09-01

    Full Text Available Zooplankton is able to respond promptly to environmental changes, producing resting forms in order to maintain populations when the conditions become unfavorable. The hatchling of the resting eggs was assessed in environments from the upper Paraná river floodplain, during the limnophase of 2008. We predicted that a higher production of these eggs and individuals’ hatchling are observed at isolated lakes, during dried period. Sediment samples were obtained with a corer sampler. The resting eggs were sorted and kept in filtered water from the same environment, in the laboratory. We recorded the occurrence of 378 resting eggs, of which 122 individuals hatched (70 cladocerans and 52 rotifers. The highest number of hatchlings was verified for the isolated lakes (84 individuals, as well the shorter time for hatchling (2 days. The hatchlings occurred mainly in September, when we registered the lowest hydrologic level of Paraná river (2.40 m. Grimaldina brazzai presented the longest time for hatchling, 44 days; and Brachionus dolabratus and B. falcatus, the shortest time, 2 days. This result suggests that the longer residence time of the water, which did not allow a renewal of food resources and limnological conditions of the environment, caused a higher stress in the zooplankton.  

  17. DNA barcoding of freshwater rotifera in Mexico: evidence of cryptic speciation in common rotifers.

    Science.gov (United States)

    García-Morales, A E; Elías-Gutiérrez, M

    2013-11-01

    DNA barcodes are useful tools to identify and discover new species in a wide range of taxa. Here, we report the first barcode study of monogonont rotifers from fresh and brackish waters in Mexico, and discuss the taxonomic implications of this work. We used DNA barcodes based on the sequence of cytochrome oxidase I to examine patterns of divergence among 417 specimens that represented 63 morphological taxa of rotifers. The mean sequence divergence among conspecific rotifer individuals was 0.75%, whereas the mean sequence divergence among congeneric taxa was 20.8%. The barcodes could discriminate between all the morphospecies identified. Moreover, the barcoding data revealed the presence of possible cryptic species in Ascomorpha ovalis, Lecane bulla, L. cornuta, L. curvicornis, L. crepida, L. lunaris, L. hastata, Platyias quadricornis, Keratella cochlearis, Brachionus calyciflorus and Testudinella patina, as well as in some forms and varieties such as B. quadridentatus f. brevispinus, B. quadridentatus f. cluniorbicularis and Mytilina ventralis var. macracantha. Barcode analysis also enabled some forms and varieties of common species to be identified as separate species. The results obtained support recent taxonomic revisions, such as the recognition of the genus Plationus, and the presence of cryptic speciation in L. bulla. This work shows that DNA barcoding identifies species effectively, can aid taxonomists by identifying cryptic species, and is an important tool for resolving taxonomic controversies. © 2013 John Wiley & Sons Ltd.

  18. The use of morphological and histological features as nutritional condition indices of Pagrus pagrus larvae

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    Marina Vera Diaz

    Full Text Available Morphometrical and histological techniques were employed to characterize Pagrus pagrus larvae nutritional condition. Larvae were reared in laboratory under controlled conditions with the main objective of testing whether these methodologies allowed finding differences between larvae from different feeding treatments. Once yolk was consumed (three days after hatching larvae were assigned to a feeding treatment: starved during the whole experiment; delayed feeding, starved during three days; fed during the entire experiment. Algae (Nannochloropsis oculata and rotifers (Brachionus plicatilis were provided to larvae for feed treatments. Larvae were fixed daily; for morphometrical purposes in 5% formaldehyde solution, and in Bouin for histological sections. Results herein obtained showed that both methodologies are sensitive enough to distinguish larvae characterized by different nutritional condition states obtained from the feeding treatments. Consequently, these methodologies could be employed in wild red porgy larvae in order to asses their nutritional condition. These techniques could also be employed to check larval quality obtained with aquaculture purposes to estimate the effects of changes in rearing protocols or kind of food supply and thus, to guaranty a higher survival of early developmental stages of reared larvae.

  19. Automated system for sampling, counting, and biological analysis of rotifer populations

    Science.gov (United States)

    Stelzer, Claus-Peter

    2010-01-01

    Zooplankton organisms with short generation times, such as rotifers, are ideal models to study general ecological and evolutionary questions on the population level, because meaningful experiments can often be completed within a couple of weeks. Yet biological analysis of such populations is often extremely time consuming, owing to abundance estimation by counting, measuring body size, or determining the investment into sexual versus asexual reproduction. An automated system for sampling and analyzing experimental rotifer populations is described. It relies on image analysis of digital photographs taken from subsamples of the culture. The system works completely autonomously for up to several weeks and can sample up to 12 cultures at time intervals down to a few hours. It allows quantitative analysis of female population density at a precision equivalent to that of conventional methods (i.e., manual counts of samples fixed in Lugol solution), and it can also recognize males, which allows detecting temporal variation of sexual reproduction in such cultures. Another parameter that can be automatically measured with the image analysis system is female body size. This feature may be useful for studies of population productivity and/or in competition experiments with clones of different body size. In this article, I describe the basic setup of the system and tests on the efficiency of data collection, and show some example data sets on the population dynamics of different strains of the rotifer Brachionus calyciflorus. PMID:21151824

  20. The Selective Use of Hypochlorite to Prevent Pond Crashes for Algae-Biofuel Production.

    Science.gov (United States)

    2015-09-21

    Although algae-biofuels have many advantages including high areal productivity, algae can be preyed upon by amoebas, protozoans, ciliates, and rotifers, particularly in open pond systems. Thus, these higher organisms need to be controlled. In this study, Chlorella kessleri was used as the algal culture and Brachionus calyciflorus as the source of predation. The effect of sodium hypochlorite (bleach) was tested with the goal of totally inhibiting the rotifer while causing minor inhibition to the alga. The 24-hr LC50 for B. calyciflorus in spring water was 0.198 mg Cl/L while the 24-hr LC50 for C. kessleri was 0.321 mg Cl/L. However, chlorine dissipates rapidly as the algae serves as reductant. Results showed a chlorine dosage between 0.45 to 0.6 mg Cl/L and a dosing interval of two hours created the necessary chlorine concentrations to inhibit predation while letting the algae grow; thus giving algae farmers a tool to prevent pond crashes. Water Environ. Res., 87 (2015).

  1. Rearing larvae of dusky grouper, Epinephelus marginatus (Lowe, 1834, (Pisces: Serranidae in a semi-extensive mesocosm

    Directory of Open Access Journals (Sweden)

    Maria Emília Cunha

    2009-10-01

    Full Text Available One of the major obstacles to propagating dusky grouper, Epinephelus marginatus, is the difficulty of rearing the early larvae. We have successfully raised dusky grouper larvae in mesocosms using a mixed diet of endogenous plankton grown in the rearing tank and an exogenous supply of Brachionus plicatilis and Artemia sp. Newly hatched larvae at an initial density of 1.3 ind.l-1 were stocked in partially shaded 3 m3 circular outdoor tanks during the summers of 2007 and 2008. Before introducing newly hatched larvae, the water was left for six days to promote plankton growth. Larval growth occurred at two different rates: i a faster rate from first feeding to the beginning of metamorphosis, and ii a slower rate at transformation. Survival at the beginning of metamorphosis was less than 10% (33 DPH in 2007 and between 25 and 50% (25 DPH in 2008. High mortalities were observed during larval transformation. The estimated minimum food requirement per grouper larvae increased more than 300% from the beginning of the notochord flexion to the beginning of metamorphosis. To meet such a high feeding requirement the number of larger prey organisms/copepods in the mesocosm should be eight times higher during this time period.

  2. Effect of addition of Navicula sp. on plankton composition and postlarvae growth of Litopenaeus vannamei reared in culture tanks with zero water exchange

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    Yllana Ferreira-Marinho

    2014-07-01

    Full Text Available The aim of this study was to evaluate the effect of the addition of Navicula sp. on plankton composition and postlarvae growth of Litopenaeus vannamei reared in culture tanks with zero water exchange systems. Four treatments were considered: zero water exchange (ZWE; ZWE with the addition of feed (ZWE-F; ZWE with the addition of Navicula sp. (ZWE-N and ZWE with the addition of feed and Navicula sp. (ZWE-FN, all in triplicate. Shrimp of 17.7 ± 0.02 mg were stocked at a density of 2500 shrimp m-3 and microalgae added on the 1st, 5th and 15th day at a density of 5x10(4 cell mL-1. The shrimp were fed a commercial feed composed by 42% crude protein four times a day except in the ZWE treatment. For data analysis we used Cochran, Shapiro-Wilk, ANOVA, Tukey and Student-t tests (P < 0.05. The most frequent genera were: Anabaena, Arcella, Asplanchma, Bosmina, Brachionus, Cylindrotheca, Daphnia, Fragilaria, Hemiaulus, Keratella, Orthoseira, Oscillatoria, Phymatodocis, Rhabdonema, Skeletonema, Sckizothrix and Ulothrix. Significant differences between treatments were observed for TAN, NO2-N, alkalinity, final weight, weight gain, final biomass, biomass gain, feed conversion ratio, specific growth rate and survival. The ZWE-FN treatment showed better production parameters, indicating the benefits of the addition of Navicula sp. as a natural food source for L. vannamei postlarvae in zero water exchange systems.

  3. Loktak Lake, Manipur, northeast India: a Ramsar site with rich rotifer (Rotifera: Eurotatoria diversity and its meta-analysis

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    Bhushan Kumar Sharma

    2016-04-01

    Full Text Available A total of 162 species (S of Rotifera belonging to 40 genera and 20 families examined from Loktak Lake, an important floodplain lake of northeast India (NEI that is one of the richest assemblages of the taxon known from the Indian sub-region. It merits biodiversity value as ~40.0% and ~62.0% of species recorded from India and NEI, respectively. One species is new to India, 23 species are new to Manipur and 14 species are new to Loktak basin. Biogeographically interesting elements included three Australasian, five Oriental, ten palaeotropical and one cosmo-subtropical species. Lecanidae > Lepadellidae > Brachionidae > Trichocercidae collectively comprised 65.4% of S; Lecane > Lepadella > Trichocerca are diverse genera; and paucity of Brachionus spp. is distinct. Loktak Rotifera indicated importance of cosmopolitan, the littoral-periphytonic and small-sized species, and ‘tropical character’. ANOVA recorded significant variations of the rotifer richness amongst three sampling sites of Loktak during June 2010–May 2012 survey. The richness followed osscillaring monthly variations and indicated lack of significant influence of any individual abioitic parameter at all three stations.

  4. Dynamics of chemically stressed populations: the deduction of population consequences from effects on individuals

    Energy Technology Data Exchange (ETDEWEB)

    Kooijman, S.A.; Metz, J.A.

    1984-06-01

    A general, simple, and explicit model for the age-dependent growth and reproduction of individuals as a function of food supply is presented. The model assumes a Holling-type functional response coupled with a von Bertalanffy body growth law, a fixed ratio between the energy utilized for reproduction and respiration, and a juvenile stage that ends as soon as the animal attains a sufficient weight. This model is shown to fit the available data on the development of Daphnia magna quite well. The model is used as a basis for studying the effects of chemicals on population growth rate, given the effects on individuals. Effects on individual growth and reproduction are reflected in a concentration-dependent relative reduction of the population growth rate. Effects on feeding rate, digestion, basal metabolism, and survival work out much more dramatically at low natural population growth rates. This already follows from a much simpler model that assumes age-independent reproduction, as exemplified to a good approximation by the rotifer Brachionus rubens. The theoretical results are supplemented with experimental evidence, implying that the stress on a population at a certain concentration of a chemical may indeed be strongly dependent on the feeding state of that population.

  5. Synthesis of water suitable as the MEPC.174(58) G8 influent water for testing ballast water management systems.

    Science.gov (United States)

    D'Agostino, Fabio; Del Core, Marianna; Cappello, Simone; Mazzola, Salvatore; Sprovieri, Mario

    2015-10-01

    Here, we describe the methodologies adopted to ensure that natural seawater, used as "influent water" for the land test, complies with the requirement that should be fulfilled to show the efficacy of the new ballast water treatment system (BWTS). The new BWTS was located on the coast of SW Sicily (Italy), and the sampled seawater showed that bacteria and plankton were two orders of magnitude lower than requested. Integrated approaches for preparation of massive cultures of bacteria (Alcanivorax borkumensis and Marinobacter hydrocarbonoclasticus), algae (Tetraselmis suecica), rotifers (Brachionus plicatilis), and crustaceans (Artemia salina) suitable to ensure that 200 m(3) of water fulfilled the international guidelines of MEPC.174(58)G8 are here described. These methodologies allowed us to prepare the "influent water" in good agreement with guidelines and without specific problems arising from natural conditions (seasons, weather, etc.) which significantly affect the concentrations of organisms at sea. This approach also offered the chance to reliably run land tests once every two weeks.

  6. Loss of sexual reproduction and dwarfing in a small metazoan.

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    Claus-Peter Stelzer

    2010-09-01

    Full Text Available Asexuality has major theoretical advantages over sexual reproduction, yet newly formed asexual lineages rarely endure. The success, or failure, of such lineages is affected by their mechanism of origin, because it determines their initial genetic makeup and variability. Most previously described mechanisms imply that asexual lineages are randomly frozen subsamples of a sexual population.We found that transitions to obligate parthenogenesis (OP in the rotifer Brachionus calyciflorus, a small freshwater invertebrate which normally reproduces by cyclical parthenogenesis, were controlled by a simple Mendelian inheritance. Pedigree analysis suggested that obligate parthenogens were homozygous for a recessive allele, which caused inability to respond to the chemical signals that normally induce sexual reproduction in this species. Alternative mechanisms, such as ploidy changes, could be ruled out on the basis of flow cytometric measurements and genetic marker analysis. Interestingly, obligate parthenogens were also dwarfs (approximately 50% smaller than cyclical parthenogens, indicating pleiotropy or linkage with genes that strongly affect body size. We found no adverse effects of OP on survival or fecundity.This mechanism of inheritance implies that genes causing OP may evolve within sexual populations and remain undetected in the heterozygous state long before they get frequent enough to actually cause a transition to asexual reproduction. In this process, genetic variation at other loci might become linked to OP genes, leading to non-random associations between asexuality and other phenotypic traits.

  7. Indicadores de condición larvaria aplicados al camarón de río del norte Cryphiops caementarius (Molina, 1782, en condiciones de cultivo controlado Larval condition indicators applied to the northern river shrimp Cryphiops caementarius (Molina, 1782, under condition of controlled cultivation

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    María C Morales

    2012-09-01

    Full Text Available Se estudia el desarrollo larvario del camarón de río del norte de Chile, Cryphiops caementarius, desde el estado de zoea 1 hasta el primer juvenil, caracterizando y analizando criterios que verificaron la aplicación de indicadores de tipo morfológico y de comportamiento para la evaluación de la condición larvaria de la especie, en condiciones de cultivo. Las larvas, se mantuvieron en cultivo, en un tanque de 250 L con agua a 20 psu y temperatura de 25 ± 1°C, controlada con termostato y con un recambio del 100% diariamente. La alimentación consistió en microalgas (Nannochloris sp. e Isochrysis sp., rotíferos (Brachionus plicatilis, nauplios de Artemia franciscana y alimento formulado. Se utilizaron cinco indicadores de carácter morfológico y de comportamiento aplicados a las larvas de C. caementarius: llenado intestinal, estado de la glándula digestiva, desarrollo branquial, comportamiento natatorio y respuesta fototáctica. Estos indicadores, permitieron determinar el estado de condición y calidad de las larvas de C. caementarius, logrando un efectivo seguimiento y asociación de cada uno de ellos, con cada estado de desarrollo larvario, estandarizando características deseables en las larvas y evidenciando resultados verificables, que permitan establecer un adecuado plan de seguimiento del cultivo, optimizar los protocolos de manejo y de alimentación de las larvas. Además de cada indicador, fue posible desglosar una amplia gama de potenciales estudios a realizar, basados en las relaciones que la morfología y el comportamiento larvario mantienen con las capacidades fisiológicas de las larvas en desarrollo.The larval development of the Chilean northern river shrimp Cryphiops caementarius was studied, from the condition of zoea 1 up to the condition of juvenile stage, analyzing and characterizing diverse criteria that allowed checking the application of morphological and behavioral indicators for the evaluation of the larval

  8. Microcrustáceos y Vibrio cholerae O1 viable no cultivable (VNC: resultados en la Cuenca del Río Salí, Tucumán, Argentina Microcrustaceans and viable but nonculturable (VNC Vibrio cholerae O1: results in the Salí River basin, Tucumán, Argentina

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    Cecilia Locascio de Mitrovich

    2010-01-01

    Full Text Available Vibrio cholerae reside habitualmente en aguas marinas y continentales. Según las condiciones ambientales y los recursos le sean “favorables” o “desfavorables”, se generan estados viables cultivables (VC o viables no cultivables (VNC respectivamente y, bajo esta última forma sobrevive. Para abordar la problemática del cólera en la Cuenca del Río Salí (Tucumán, Argentina, se realizaron muestreos durante los años 2003-2005 donde se consideraron aspectos fisicos, químicos, biológicos y sanitarios. Para evaluar los probables reservorios del patógeno, se analizó el zooplancton del Río Salí (Canal Norte y Banda Río Salí y Río Lules. La mayor representatividad taxonómica la registraron los copépodos, especialmente Eucyclops neumani (Pesta, 1927, junto a Acanthocyclops robustus (Sars, 1863, Metacyclops sp., Paracyclops chiltoni y Notodiaptomus incompositus (Brian, 1925, además de algunos rotíferos y cladóceros como (Lecane sp., y (Brachionus sp., Moina sp. y Leydigia sp.. La frecuencia de ocurrencia fue baja y no superó el 25%. El Canal Norte fue ambiente más propicio por la riqueza específica, abundancia y constancia de la comunidad. Las variables fisicas y químicas asociadas al zooplancton coincidirían con los valores que por nuestros registros y los antecedentes, se conocen para el desarrollo del patógeno. En el período estival hubo coincidencia entre la presencia de la forma VNC de V. cholerae O1 (inmunofluorescencia con anticuerpos anti O1 y el desarrollo del zooplancton. Se observaron formas VNC sobre apéndices o estructuras de copépodos ciclopoideos y cladóceros quidóridos, reflejando probablemente afinidad con sustratos quitinosos.Vibrio cholerae habitually lives in marine and continental waters. According to "favourable" or "unfavourable" resources and environmental conditions, viable (VC or viable non-culturable (VNC states will be generated, surviving only the latter form. To address the problem of

  9. Fecundity, growth, and survival of the angelfish Pterophyllum scalare (Perciformes: Cichlidae under laboratory conditions

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    Armando A Ortega-Salas

    2009-09-01

    Full Text Available The freshwater angelfishes (Pterophyllum are South American cichlids that have become very popular among aquarists, yet scarce information on their culture and aquarium husbandry exists. We studied Pterophyllum scalare to analyze dietary effects on fecundity, growth, and survival of eggs and larvae during 135 days. Three diets were used: A decapsulated cysts of Artemia, B commercial dry fish food, and C a mix diet of the rotifer Brachionus plicatilis and the cladoceran Daphnia magna. The initial larval density was 100 organisms in each 40L aquarium. With diet A, larvae reached a maximum weight of 3.80g, a total length of 6.3 cm, and a height of 5.8cm; with diet B: 2.80g, 4.81cm, and 4.79cm, and with diet C: 3.00g, 5.15cm, and 5.10cm, respectively. Significant differences were observed between diet A, and diet B and C, but no significantly differences were observed between diets B and C. Fecundity varied from 234 to 1 082 eggs in 20 and 50g females, respectively. Egg survival ranged from 87.4% up to 100%, and larvae survival (80 larvae/40L aquarium from 50% to 66.3% using diet B and A, respectively. Live food was better for growing fish than the commercial balanced food diet. Fecundity and survival are important factors in planning a good production of angelfish. Rev. Biol. Trop. 57 (3: 741-747. Epub 2009 September 30.Se realizaron estudios de cultivo en laboratorio del pez ángel, Pterophyllum scalare, para analizar los efectos de su dieta en la fecundidad, crecimiento y sobrevivencia en huevos y larvas por un período 135 días. Tres dietas diferentes se utilizaron A quistes decapsulados de Artemia, B comida comercial seca para pez, C una mezcla de rotíferos, Brachionus plicatilis y el cladocero, Daphnia magna. La densidad inicial de larvas en acuarios de 40L fue de 100 organismos. Utilizando la dieta A, las larvas alcanzaron un peso máximo de 3.80g, una longitud total de 6.3cm y una altura de 5.8cm; utilizando la dieta B, fue de 2.80g, 4

  10. Efficiency of a cleanup technology to remove mercury from natural waters by means of rice husk biowaste: ecotoxicological and chemical approach.

    Science.gov (United States)

    Rocha, Luciana S; Lopes, I; Lopes, Cláudia B; Henriques, Bruno; Soares, Amadeu M V M; Duarte, Armando C; Pereira, Eduarda

    2014-01-01

    In the present work, the efficiency of rice husk to remove Hg(II) from river waters spiked with realistic environmental concentrations of this metal (μg L(-1) range) was evaluated. The residual levels of Hg(II) obtained after the remediation process were compared with the guideline values for effluents discharges and water for human consumption, and the ecotoxicological effects using organisms of different trophic levels were assessed. The rice husk sorbent proved to be useful in decreasing Hg(II) contamination in river waters, by reducing the levels of Hg(II) to values of ca. 8.0 and 34 μg L(-1), for an Hg(II) initial concentration of 50 and 500 μg L(-1), respectively. The remediation process with rice husk biowaste was extremely efficient in river waters spiked with lower levels of Hg(II), being able to eliminate the toxicity to the exposed organisms algae Pseudokirchneriella subcapitata and rotifer Brachionus calyciflorus and ensure the total survival of Daphnia magna species. For concentrations of Hg(II) tenfold higher (500 μg L(-1)), the remediation process was not adequate in the detoxification process, still, the rice husk material was able to reduce considerably the toxicity to the bacteria Vibrio fischeri, algae P. subcapitata and rotifer B. calyciflorus, whose responses where fully inhibited during its exposure to the non-remediated river water. The use of a battery of bioassays with organisms from different trophic levels and whose sensitivity revealed to be different and dependent on the levels of Hg(II) contamination proved to be much more accurate in predicting the ecotoxicological hazard assessment of the detoxification process by means of rice husk biowaste.

  11. Long-term competitive dynamics of two cryptic rotifer species: diapause and fluctuating conditions.

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    Carmen Gabaldón

    Full Text Available Life-history traits may have an important role in promoting species coexistence. However, the complexity of certain life cycles makes it difficult to draw conclusions about the conditions for coexistence or exclusion based on the study of short-term competitive dynamics. Brachionus plicatilis and B. manjavacasare two cryptic rotifer species co-occurring in many lakes on the Iberian Peninsula. They have a complex life cycle in which cyclical parthenogenesis occurs with diapausing stages being the result of sexual reproduction. B. plicatilis and B. manjavacasare identical in morphology and size, their biotic niches are broadly overlapping, and they have similar competitive abilities. However, the species differ in life-history traits involving sexual reproduction and diapause, and respond differently to salinity and temperature. As in the case of certain other species that are extremely similar in morphology, a fluctuating environment are considered to be important for their coexistence. We studied the long-term competitive dynamics of B. plicatilis and B. manjavacas under different salinity regimes (constant and fluctuating. Moreover, we focused on the dynamics of the diapausing egg bank to explore how the outcome of the entire life cycle of these rotifers can work to mediate stable coexistence. We demonstrated that these species do not coexist under constant-salinity environment, as the outcome of competition is affected by the level of salinity-at low salinity, B. plicatilis excluded B. manjavacas, and the opposite outcome occurred at high salinity. Competitive dynamics under fluctuating salinity showed that the dominance of one species over the other also tended to fluctuate. The duration of co-occurrence of these species was favoured by salinity fluctuation and perhaps by the existence of a diapausing egg bank. Stable coexistence was not found in our system, which suggests that other factors or other salinity fluctuation patterns might act as

  12. Morphological similarity and ecological overlap in two rotifer species.

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    Carmen Gabaldón

    Full Text Available Co-occurrence of cryptic species raises theoretically relevant questions regarding their coexistence and ecological similarity. Given their great morphological similitude and close phylogenetic relationship (i.e., niche retention, these species will have similar ecological requirements and are expected to have strong competitive interactions. This raises the problem of finding the mechanisms that may explain the coexistence of cryptic species and challenges the conventional view of coexistence based on niche differentiation. The cryptic species complex of the rotifer Brachionus plicatilis is an excellent model to study these questions and to test hypotheses regarding ecological differentiation. Rotifer species within this complex are filtering zooplankters commonly found inhabiting the same ponds across the Iberian Peninsula and exhibit an extremely similar morphology-some of them being even virtually identical. Here, we explore whether subtle differences in body size and morphology translate into ecological differentiation by comparing two extremely morphologically similar species belonging to this complex: B. plicatilis and B. manjavacas. We focus on three key ecological features related to body size: (1 functional response, expressed by clearance rates; (2 tolerance to starvation, measured by growth and reproduction; and (3 vulnerability to copepod predation, measured by the number of preyed upon neonates. No major differences between B. plicatilis and B. manjavacas were found in the response to these features. Our results demonstrate the existence of a substantial niche overlap, suggesting that the subtle size differences between these two cryptic species are not sufficient to explain their coexistence. This lack of evidence for ecological differentiation in the studied biotic niche features is in agreement with the phylogenetic limiting similarity hypothesis but requires a mechanistic explanation of the coexistence of these species not

  13. Comparative transcriptome analysis of obligately asexual and cyclically sexual rotifers reveals genes with putative functions in sexual reproduction, dormancy, and asexual egg production.

    Science.gov (United States)

    Hanson, Sara J; Stelzer, Claus-Peter; Welch, David B Mark; Logsdon, John M

    2013-06-19

    Sexual reproduction is a widely studied biological process because it is critically important to the genetics, evolution, and ecology of eukaryotes. Despite decades of study on this topic, no comprehensive explanation has been accepted that explains the evolutionary forces underlying its prevalence and persistence in nature. Monogonont rotifers offer a useful system for experimental studies relating to the evolution of sexual reproduction due to their rapid reproductive rate and close relationship to the putatively ancient asexual bdelloid rotifers. However, little is known about the molecular underpinnings of sex in any rotifer species. We generated mRNA-seq libraries for obligate parthenogenetic (OP) and cyclical parthenogenetic (CP) strains of the monogonont rotifer, Brachionus calyciflorus, to identify genes specific to both modes of reproduction. Our differential expression analysis identified receptors with putative roles in signaling pathways responsible for the transition from asexual to sexual reproduction. Differential expression of a specific copy of the duplicated cell cycle regulatory gene CDC20 and specific copies of histone H2A suggest that such duplications may underlie the phenotypic plasticity required for reproductive mode switch in monogononts. We further identified differential expression of genes involved in the formation of resting eggs, a process linked exclusively to sex in this species. Finally, we identified transcripts from the bdelloid rotifer Adineta ricciae that have significant sequence similarity to genes with higher expression in CP strains of B. calyciflorus. Our analysis of global gene expression differences between facultatively sexual and exclusively asexual populations of B. calyciflorus provides insights into the molecular nature of sexual reproduction in rotifers. Furthermore, our results offer insight into the evolution of obligate asexuality in bdelloid rotifers and provide indicators important for the use of monogononts

  14. Spatial variations in zooplankton diversity in waters contaminated with composite effluents

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    Asitava CHATTERJEE

    2007-08-01

    Full Text Available Zooplankton species are cosmopolitan in their clean freshwater habitat and are also found in industrial and municipal wastewaters. The present study records for the first time the aspects of zooplankton diversity in relation to physico-chemical environment of five selected sites of the East Calcutta wetlands, a Ramsar site of Kolkata city, India, heavily contaminated by industrial and municipal wastewaters. The study revealed the occurrence of 22 species of zooplankton, among these 3 species of Cladocera, 2 species of Copepoda, 15 species of Rotifera, and 2 species of Ostracoda were recorded. The copepod Mesocyclops leuckarti was found in all the five sites, rotifers Asplanchna brightwelli, Brachionus angularis, B. calyciflorus and Cladocera Ceriodaphnia cornuta were found in four sites; Moina micrura and Diaphanosoma sarsi were found at three sites. Site wise variation in dominance, diversity, evenness and richness were calculated. Site 1, a fish-pond that stabilized composite wastewater, showed the maximum species richness having 17 species, while Site 2, SWF wastewater carrying canal, showed only 4 species. The calculated Jack 1 values of Sites 1 to 5 were 21.78, 3.77, 18.63, 12.5 and 16.95 respectively. Shannon-Wiener species diversity index (H/ values were almost similar for all the three relatively less polluted sites viz, Site 1 (1.959, Site 4 (2.010, Site 5 (2.047. However, at highly polluted sites viz., 2 and 3, H/ value of 1.336 and 0.984 respectively, were calculated. Simpson’s Dominance index (Dsimp value was highest at Site 3 (0.618 indicating maximum dominance, whereas at Site 5 dominance was lowest (0.1680 and diversity was highest. We discuss the role of zooplankton in the amelioration of wastewater.

  15. Use of neutralized industrial residue to stabilize trace elements (Cu, Cd, Zn, As, Mo, and Cr) in marine dredged sediment from South-East of France.

    Science.gov (United States)

    Taneez, Mehwish; Marmier, Nicolas; Hurel, Charlotte

    2016-05-01

    Management of marine dredged sediments polluted with trace elements is prime issue in the French Mediterranean coast. The polluted sediments possess ecological threats to surrounding environment on land disposal. Therefore, stabilization of contaminants in multi-contaminated marine dredged sediment is a promising technique. Present study aimed to assess the effect of gypsum neutralized bauxaline(®) (bauxite residue) to decrease the availability of pollutants and inherent toxicity of marine dredged sediment. Bauxaline(®), (alumia industry waste) contains high content of iron oxide but its high alkalinity makes it not suitable for the stabilization of all trace elements from multi-contaminated dredged sediments. In this study, neutralized bauxaline(®) was prepared by mixing bauxaline(®) with 5% of plaster. Experiments were carried out for 3 months to study the effect of 5% and 20% amendment rate on the availability of Cu, Cd, Zn, As, Mo, and Cr. Trace elements concentration, pH, EC and dissolved organic carbon were measured in all leachates. Toxicity of leachates was assessed against marine rotifers Brachionus plicatilis. The Results showed that both treatments have immobilization capacity against different pollutants. Significant stabilization of contaminants (Cu, Cd, Zn) was achieved with 20% application rate whereas As, Mo, and Cr were slightly stabilized. Toxicity results revealed that leachates collected from treated sediment were less toxic than the control sediment. These results suggest that application of neutralized bauxaline(®) to dredged sediment is an effective approach to manage large quantities of dredged sediments as well as bauxite residue itself. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Global isolation by distance despite strong regional phylogeography in a small metazoan

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    Mills Scott

    2007-11-01

    Full Text Available Abstract Background Small vagile eukaryotic organisms, which comprise a large proportion of the Earth's biodiversity, have traditionally been thought to lack the extent of population structuring and geographic speciation observed in larger taxa. Here we investigate the patterns of genetic diversity, amongst populations of the salt lake microscopic metazoan Brachionus plicatilis s. s. (sensu stricto (Rotifera: Monogononta on a global scale. We examine the phylogenetic relationships of geographic isolates from four continents using a 603 bp fragment of the mitochondrial COI gene to investigate patterns of phylogeographic subdivision in this species. In addition we investigate the relationship between genetic and geographic distances on a global scale to try and reconcile the paradox between the high vagility of this species and the previously reported patterns of restricted gene flow, even over local spatial scales. Results Analysis of global sequence diversity of B. plicatilis s. s. reveals the presence of four allopatric genetic lineages: North American-Far East Asian, Western Mediterranean, Australian, and an Eastern Mediterranean lineage represented by a single isolate. Geographically orientated substructure is also apparent within the three best sampled lineages. Surprisingly, given this strong phylogeographic structure, B. plicatilis s. s. shows a significant correlation between geographic and genetic distance on a global scale ('isolation by distance' – IBD. Conclusion Despite its cosmopolitan distribution and potential for high gene flow, B. plicatilis s. s. is strongly structured at a global scale. IBD patterns have traditionally been interpreted to indicate migration-drift equilibrium, although in this system equilibrium conditions are incompatible with the observed genetic structure. Instead, we suggest the pattern may have arisen through persistent founder effects, acting in a similar fashion to geographic barriers for larger

  17. CHRONIC TOXICITY OF ALUMINUM, AT A PH OF 6, TO FRESHWATER ORGANISMS: EMPIRICAL DATA FOR THE DEVELOPMENT OF INTERNATIONAL REGULATORY STANDARDS/CRITERIA.

    Science.gov (United States)

    Cardwell, Allison S; Adams, William J; Gensemer, Robert W; Nordheim, Eirik; Santore, Robert C; Ryan, Adam C; Stubblefield, William A

    2017-07-01

    The chemistry, bioavailability, and toxicity of aluminum (Al) in the aquatic environment is complex and affected by a wide-range of water quality characteristics (pH, hardness, dissolved organic carbon). Data gaps in Al ecotoxicology exist for pH ranges representative of natural surface waters (pH 6-8). To address these gaps, a series of chronic toxicity tests were performed at pH 6 with eight freshwater species, including two fish (Pimephales promelas and Danio rerio); an oligochaete (Aeolosoma sp.); a rotifer (Brachionus calyciflorus); a snail (Lymnaea stagnalis); an amphipod (Hyalella azteca); a midge (Chironomus riparius); and an aquatic plant (Lemna minor). The 10% effect concentrations (EC10s as µg total Al/L) ranged from 98 for D. rerio to 2,175 for L. minor. From these data and additional published data, species-sensitivity distributions (SSDs) were developed to derive concentrations protective of 95% of tested species (i.e., HC5-50). A generic HC5-50 (not adjusted for bioavailability) of 74.4 µg total Al/L was estimated using the SSD. An Al specific biotic ligand model (BLM) was used to develop SSDs normalized for bioavailability based upon site-specific water quality characteristics. Normalized HC5-50s ranged from 93.7 to 534 µg total Al/L for waters representing a range of European ecoregions, while a chronic HC5 calculated using USEPA aquatic life criteria methods (i.e., a Continuous Criterion Concentration [CCC]) was 125 µg total Al/L when normalized to Lake Superior water in the US. HC5-50 and CCC values for site-specific waters other than those presented here can be obtained using the Al BLM. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  18. Study of the chemistry and biota of acid and alkaline ponds at the Smoking Hills, N. W. T

    Energy Technology Data Exchange (ETDEWEB)

    Havas, M.

    1981-01-01

    Sulphur dioxide and sulphuric acid aerosols, emitted from spontaneously burning bituminous shales at the Smoking Hills, have significantly altered nearby tundra ponds. The antiquity of these burns, the intensity of the emissions, and the relatively localized but severe effects have produced an ideal field-laboratory for the study of the long-term consequences of acidification. Many of the once alkaline ponds have become acidic. A bimodal pH distribution of the ponds shows peaks at pH 8 and pH3, which correspond to the two dominant buffering systems in this area. Metal concentrations are elevated in the acidified ponds, especially below pH 4.5. Changes in pH in the soils and sediments, relate to aerial deposition and differential leaching rates. Biological diversity is significantly reduced in the acidified ponds. The few species that can survive are abundant. These include the alga Euglena mutabilis, the mosses Drepanocladus exannulatus and Leptodictyum riparium, the rotifer Brachionus urceolaris, and the red Diptera Chironomus riparius. Crustaceans are rare or absent from acidified ponds. Bioassays revealed that crustaceans were sensitive to pH below 4.5. Insect larvae, in contrast, were considerably more tolerant. Metals especially Al, increased the toxicity of the acidified pond water. Acid-sensitive invertebrates were unable to regulate osmotically important elements at low pH. The net loss of sodium by Daphnia was due primarily to an accelerated rate of sodium loss. Sodium uptake was also affected, but only at very low pH's. Daphnia middendorffiana was able to recover following brief exposure to pH 4.0 when restored to a neutral solution. Secondary fungal infection was observed and many interfere with long-term survival in acid waters.

  19. Zooplankton of an urban coastal lagoon: composition and association with environmental factors and summer fish kill

    Directory of Open Access Journals (Sweden)

    Leonardo C. e Souza

    2011-06-01

    Full Text Available Zooplankton may be regarded as a sensitive tool for monitoring environmental variations in coastal lagoons due to their ability to immediately react to changes in the water column trophic features and salinity levels. As a coastal lagoon with a broad history of anthropic influence, Rodrigo de Freitas Lagoon (Rio de Janeiro, Brazil is widely used for water sports and artisanal fishing. The present study aimed to expand the knowledge base about zooplankton in the Rodrigo de Freitas Lagoon by assessing the composition and time-spatial distribution of the major zooplankton groups. Samples were collected fortnightly from at four distinct sampling points August 2001 to July 2002. At each point, salinity, temperature, dissolved oxygen and water transparency were measured. During the study period, the lagoon behaved as an spatially homogeneous environment in what regards the abiotic variables. However, all these variables showed significant differences along the time, mainly related to seasonality (air temperature and rainy and dry periods. The zooplankton community showed low taxonomic richness, with the predominance of species commonly found in coastal lagoons, especially with mesohaline conditions, as well as those found in estuaries. An interesting fact was the rise in zooplankton abundance at all sampling points right after a fish kill event. Such increase was caused mainly by the Brachionus plicatilis O.F. Müller 1786 species. Thus, the zooplankton community was affected by physical and chemical factors, mainly by the dissolved oxygen decline event and variations in the influx of seawater into the lagoon. In addition, phytoplankton availability and fish predation pressure were suggested as important regulating factors of the zooplankton community.

  20. Different types of interactions of links in artificial and natural ecosystems under anthropogenic pressure

    Science.gov (United States)

    Somova, Lydia; Pisman, Tamara; Mikheeva, Galina; Pechurkin, Nickolay

    The life of organisms in an ecosystem depends not only on abiotic factors, but also on the interaction of organisms in which they come with each other. The study of mechanisms of the bioregulation based on ecological - biochemical interactions of ecosystem links is necessary to know the ecosystem development, its stability, survival of ecosystem organisms. It is of high importance as for the creation of artificial ecosystems, and also for the study of natural ecosystems under anthropogenic pressure on them. To create well-functioning ecosystems is necessary to study and consider the basic types of relationships between organisms. The basic types of interactions between organisms have been studied with simple terrestrial and water ecosystems. 1. The interaction of microbiocenoses and plants were studied in experiments with agrocenoses. Microbiocenosis proposed for increase of productivity of plants and for obtaining ecologically pure production of plants has been created taking into account mutual relationships between species of microorganisms. 2. The experimental model of the atmosphere closed «autotroph - heterotroph» system in which heterotrophic link was the mixed population of yeasts (Candida utilis and Candida guilliermondii) was studied. The algae Chlorella vulgaris was used as an autotroph link. It was shown, that the competition result for heterotrophic link depended on strategy of populations of yeast in relation to a substrate and oxygen utilization. 3. As a result of experimental and theoretical modelling of a competition of algae Chlorella vulgaris and Scenedesmus quadricauda at continuous cultivation, the impossibility of their coexistence in the conditions of limitation on nitrogen was shown. 4. Pray-predator interactions between algae (Chlorella vulgaris, Scenedesmus quadricauda) and invertebrates (Paramecium caudatum, Brachionus plicatilis) were studied in experimental closed ecosystem. This work was partly supported by the Russian Foundation for

  1. A Multidisciplinary Assessment of River Surface Water Quality in Areas Heavily Influenced by Human Activities.

    Science.gov (United States)

    Charalampous, Nikolina; Kindou, Aggeliki; Vlastos, Dimitris; Tsarpali, Vasiliki; Antonopoulou, Maria; Konstantinou, Ioannis; Dailianis, Stefanos

    2015-08-01

    The present study could serve as a multidisciplinary approach for the assessment of river surface water quality with the use of chemical and biological methods. Specifically, physicochemical parameters, heavy metals, and pesticides were measured in water samples from three different stations (sampling station S1, S2, and S3) along Asopos River (Greece). In parallel, algal species (primary producers)-such as Scenedesmus rubescens and Chlorococcum sp.; consumer invertebrate species, such as the fairy shrimp Thamnocephalus platyurus and the rotifer Brachionus calyciflorus; as well as human lymphocytes-were exposed to those samples for assessing their toxic and genotoxic/mutagenic effects. According to the results, although the values of almost all of the physicochemical parameters tested, heavy metals (zinc, cadmium, lead, and mercury) and pesticides were lower than or within the respective environmental quality standards, thus offering no clear evidence for their natural or anthropogenic origin. Values recorded for nickel, chromium, hexavalent chromium, and malathion represent a typical case of mixed influence from natural and anthropogenic enrichments. In contrast, the algal growth arrest, the acute toxic effects on the freshwater invertebrates, and the increased micronuclei frequencies observed in human lymphocytes showed the presence of human-derived hazardous substances, which were hardly determinable with the use of conventional chemical methods. Given that the presence of priority pollutants in river surface waters, heavily burdened by anthropogenic activities, could give no clear evidence for their biological risk, the results of the present study showed that chemical and biological assays should be applied in parallel, thus serving as a reliable tool for the assessment of river water quality.

  2. Unexpected increases in rotifer resting egg abundances during the period of contamination of Lake Orta

    Directory of Open Access Journals (Sweden)

    Roberta Piscia

    2016-04-01

    Full Text Available Despite their ecological importance and rapid response to environmental changes, rotifers are rarely included in palaeolimnological studies. Here, we describe changes in abundance (ABD and morphotype (MTs diversity of rotifer resting eggs in the sediments of deep subalpine Lake Orta, Italy, covering a period prior to (pre- 1926, during long-term ammonia and metal pollution from a rayon factory, and subsequent recovery of water quality. Following the pollution and bacterial oxidation of the ammonia, Lake Orta became the largest and deepest acid lake in Europe. Recovery of water quality followed both a ban on the discharge of industrial wastes, and a liming intervention in 1989 and 1990. We sectioned a sediment core collected from the deepest part of the lake (ORTA 07/2A to provide a high  time resolution, given the ca. 3-4 y cm-1 of sediment accumulation. Rotifer resting egg (RRE abundance and morphotypes were examined from the sediments and compared to limnological variables indicating the pollution. Rotifer resting egg abundance significantly increased with lake contamination (r=0.609 and -0.624 for copper and pH, respectively; P<0.001; n=27. A lake-water copper concentration threshold of ca. 40 µg L-1discriminated among pre-, during-, and post- pollution compositions of the rotifer morphotype assemblages. Diversity and morphotype richness increased during the recovery from copper pollution and with complete restoration from acidity, while abundance increased during pollution. The persistence of presumably viable Brachionus resting eggs and of hatched egg cases during the heavy pollution phase suggests that, unlike most other organisms, which were extirpated by the pollution of the lake, rotifers survived producing resting eggs, which secured future generations.

  3. Toxicity of algal-derived aldehydes to two invertebrate species: Do heavy metal pollutants have a synergistic effect?

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Rebecca L. [School of Marine Science and Technology, University of Newcastle upon Tyne, Ridley Building, Claremont Road, Newcastle upon Tyne NE1 7RU (United Kingdom)]. E-mail: r.l.taylor@ncl.ac.uk; Caldwell, Gary S. [School of Marine Science and Technology, University of Newcastle upon Tyne, Ridley Building, Claremont Road, Newcastle upon Tyne NE1 7RU (United Kingdom); Bentley, Matthew G. [School of Marine Science and Technology, University of Newcastle upon Tyne, Ridley Building, Claremont Road, Newcastle upon Tyne NE1 7RU (United Kingdom)

    2005-08-15

    The recent discovery of the production of anti-proliferative aldehydes in a variety of microalgal species has lead to considerable investigation into the effects of these toxins on aquatic invertebrates. Studies have, however, rarely considered the impact pollutants may have on grazer responses to algal toxins. In this study, the acute toxicities of five aldehydes to the rotifer Brachionus plicatilis and nauplii of the brine shrimp Artemia salina are examined using immersion assays. In addition, the effect of a representative of these aldehydes in the presence of sub-lethal levels of heavy metals was examined. B. plicatilis generally showed greater sensitivity to the aldehydes than A. salina. The polyunsaturated 2-trans,4-trans-decadienal was the most toxic to both species having 24 h LD{sub 50} values of 7 and 20 {mu}M for B. plicatilis and A. salina, respectively. The remaining aldehydes had different orders of toxicity for the two species with a stronger relationship observed between mortality and aldehyde carbon-chain length for A. salina whereas B. plicatilis mortality showed a stronger dependence on the presence of carbon-carbon double bonds in the aldehydes. The presence of 1 {mu}M of copper sulphate in solutions of decadienal resulted in the reduction of the 24 h LD{sub 50} of decadienal by approximately a third for both species. 1 {mu}M of copper chloride in solutions of decadienal reduced the 24 h LD{sub 50} of decadienal to A. salina nauplii by approximately 11% and 1 {mu}M zinc sulphate caused a reduction of only 3%. Pre-exposure of the organisms to 1 {mu}M copper sulphate had no significant impact on their subsequent mortality in decadienal. The ecological implications and the possible mechanisms for the action of copper sulphate on the response of organisms to decadienal are discussed.

  4. Aeolian transport of biota with dust: A wind tunnel experiment

    Science.gov (United States)

    Rivas, J. A., Jr.; Gill, T. E.; Van Pelt, R. S.; Walsh, E.

    2015-12-01

    Ephemeral wetlands are ideal sources for dust emission, as well as repositories for dormant stages of aquatic invertebrates. An important component of invertebrate dispersal and colonization to new areas is the ability to be entrained into the atmosphere. Aquatic invertebrate eggs fall within the size of dust and sand grains (30-600μm), are less dense and aerodynamically shaped. We have shown previously that aquatic invertebrates can be dispersed long distances in dust storms but the extent of transport of taxa based on diapausing egg size/morphology has not been investigated. Here, we control the wind erosion process in a wind tunnel to test entrainment of diapausing stages of brine shrimp, clam shrimp, tadpole shrimp, fairy shrimp, Daphnia, and the rotifers Brachionus plicatilis and B. calyciflorus into the air by saltation. Diapausing eggs were mixed with sterilized wind-erodible soil. The soil/egg mixture was moistened with distilled water and air dried to form a crust. Dust was generated in a wind tunnel by releasing sand grains that act as saltator material similar to wind-entrained natural sands. Maximum wind velocity was 10m/s and entrained particles were sampled through an isokinetic horizontal intake opening. Aeolian sediment was collected from three points in the system; transfer section for coarse sediment, the pan subtending a settling chamber for finer saltation-sized sediment, and two paper filters for suspension-sized sediment. Samples were then passed through 250 and 350 μm sieves to remove abrader sand and rehydrated with various sterile media depending on the type of organism. We retrieved viable brine, fairy, and tadpole shrimp, ostracods, Daphnia, and diapausing eggs of the rotifers after hydration. This experiment demonstrates that resting stages of many invertebrates can be wind-eroded due to size and egg morphology and remain viable under controlled conditions mimicking dust emission.

  5. EST based phylogenomics of Syndermata questions monophyly of Eurotatoria

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    Bucher Gregor

    2008-12-01

    Full Text Available Abstract Background The metazoan taxon Syndermata comprising Rotifera (in the classical sense of Monogononta+Bdelloidea+Seisonidea and Acanthocephala has raised several hypotheses connected to the phylogeny of these animal groups and the included subtaxa. While the monophyletic origin of Syndermata and Acanthocephala is well established based on morphological and molecular data, the phylogenetic position of Syndermata within Spiralia, the monophyletic origin of Monogononta, Bdelloidea, and Seisonidea and the acanthocephalan sister group are still a matter of debate. The comparison of the alternative hypotheses suggests that testing the phylogenetic validity of Eurotatoria (Monogononta+Bdelloidea is the key to unravel the phylogenetic relations within Syndermata. The syndermatan phylogeny in turn is a prerequisite for reconstructing the evolution of the acanthocephalan endoparasitism. Results Here we present our results from a phylogenomic approach studying i the phylogenetic position of Syndermata within Spiralia, ii the monophyletic origin of monogononts and bdelloids and iii the phylogenetic relations of the latter two taxa to acanthocephalans. For this analysis we have generated EST libraries of Pomphorhynchus laevis, Echinorhynchus truttae (Acanthocephala and Brachionus plicatilis (Monogononta. By extending these data with database entries of B. plicatilis, Philodina roseola (Bdelloidea and 25 additional metazoan species, we conducted phylogenetic reconstructions based on 79 ribosomal proteins using maximum likelihood and bayesian approaches. Our findings suggest that the phylogenetic position of Syndermata within Spiralia is close to Platyhelminthes, that Eurotatoria are not monophyletic and that bdelloids are more closely related to acanthocephalans than monogononts. Conclusion Mapping morphological character evolution onto molecular phylogeny suggests the (partial or complete reduction of the corona and the emergence of a retractable

  6. EST based phylogenomics of Syndermata questions monophyly of Eurotatoria.

    Science.gov (United States)

    Witek, Alexander; Herlyn, Holger; Meyer, Achim; Boell, Louis; Bucher, Gregor; Hankeln, Thomas

    2008-12-29

    The metazoan taxon Syndermata comprising Rotifera (in the classical sense of Monogononta+Bdelloidea+Seisonidea) and Acanthocephala has raised several hypotheses connected to the phylogeny of these animal groups and the included subtaxa. While the monophyletic origin of Syndermata and Acanthocephala is well established based on morphological and molecular data, the phylogenetic position of Syndermata within Spiralia, the monophyletic origin of Monogononta, Bdelloidea, and Seisonidea and the acanthocephalan sister group are still a matter of debate. The comparison of the alternative hypotheses suggests that testing the phylogenetic validity of Eurotatoria (Monogononta+Bdelloidea) is the key to unravel the phylogenetic relations within Syndermata. The syndermatan phylogeny in turn is a prerequisite for reconstructing the evolution of the acanthocephalan endoparasitism. Here we present our results from a phylogenomic approach studying i) the phylogenetic position of Syndermata within Spiralia, ii) the monophyletic origin of monogononts and bdelloids and iii) the phylogenetic relations of the latter two taxa to acanthocephalans. For this analysis we have generated EST libraries of Pomphorhynchus laevis, Echinorhynchus truttae (Acanthocephala) and Brachionus plicatilis (Monogononta). By extending these data with database entries of B. plicatilis, Philodina roseola (Bdelloidea) and 25 additional metazoan species, we conducted phylogenetic reconstructions based on 79 ribosomal proteins using maximum likelihood and bayesian approaches. Our findings suggest that the phylogenetic position of Syndermata within Spiralia is close to Platyhelminthes, that Eurotatoria are not monophyletic and that bdelloids are more closely related to acanthocephalans than monogononts. Mapping morphological character evolution onto molecular phylogeny suggests the (partial or complete) reduction of the corona and the emergence of a retractable anterior end (rostrum, proboscis) before the

  7. Does haplodiploidy purge inbreeding depression in rotifer populations?

    Directory of Open Access Journals (Sweden)

    Ana M Tortajada

    Full Text Available BACKGROUND: Inbreeding depression is an important evolutionary factor, particularly when new habitats are colonized by few individuals. Then, inbreeding depression by drift could favour the establishment of later immigrants because their hybrid offspring would enjoy higher fitness. Rotifers are the only major zooplanktonic group where information on inbreeding depression is still critically scarce, despite the fact that in cyclical parthenogenetic rotifers males are haploid and could purge deleterious recessive alleles, thereby decreasing inbreeding depression. METHODOLOGY/PRINCIPAL FINDINGS: We studied the effects of inbreeding in two populations of the cyclical parthenogenetic rotifer Brachionus plicatilis. For each population, we compared both the parental fertilization proportion and F1 fitness components from intraclonal (selfed and interclonal (outcrossed crosses. The parental fertilization proportion was similar for both types of crosses, suggesting that there is no mechanism to avoid selfing. In the F1 generation of both populations, we found evidence of inbreeding depression for the fitness components associated with asexual reproduction; whereas inbreeding depression was only found for one of the two sexual reproduction fitness components measured. CONCLUSIONS/SIGNIFICANCE: Our results show that rotifers, like other major zooplanktonic groups, can be affected by inbreeding depression in different stages of their life cycle. These results suggest that haplodiploidy does not purge efficiently deleterious recessive alleles. The inbreeding depression detected here has important implications when a rotifer population is founded and intraclonal crossing is likely to occur. Thus, during the foundation of new populations inbreeding depression may provide opportunities for new immigrants, increasing gene flow between populations, and affecting genetic differentiation.

  8. Temporal variation in plankton assemblages and physicochemistry of Devils Lake, North Dakota

    Science.gov (United States)

    Leland, H.V.; Berkas, W.R.

    1998-01-01

    the rotifers Brachionus spp., Filinia longiseta, Keratella cochlearis and K. quadrata) also indicated variation in algal populations related to grazing. ?? 1998 Kluwer Academic Publishers.

  9. Filming of zooplankton: a case study of rotifer males and Daphnia magna

    Directory of Open Access Journals (Sweden)

    Pierluigi Colangeli

    2015-11-01

    Full Text Available Filming live organisms can give new insights into the hidden life of plankton. Accessibly priced digital cameras are now available for a large range of users. Here, we demonstrate the technical setup and workflow of using a single-lens reflex (DSLR camera to film the behaviour of males of two rotifer species, Brachionus angularis Gosse (1851 and Keratella cochlearis Gosse (1851, and of the cladoceran Daphnia magna Straus (1820. Rotifers are cyclical parthenogens that produce males only under certain environmental conditions. Thus, knowledge on rotifer males is still limited because of their ephemeral nature and because they are often smaller than females. We filmed males of B. angularis and K. cochlearis with a DSLR camera connected to a compound microscope to better understand their morphology and behaviour in comparison to conspecific females. While written descriptions have their scientific value, seeing is complementary because everyone can verify what has been described. We made our videos publicly accessible through links connected to the paper. Our videos are, to our best knowledge, the first on males of B. angularis and K. cochlearis. Furthermore, we filmed the behavioural response of D. magna to ultraviolet (UV radiation with a macro lens attached to the DSLR camera. Approaches like this are valuable tools in environmental teaching. To see live organisms with one’s own eyes may contribute to raising public awareness about the value of water resources and their hidden communities. In summary, filming can be a valuable tool to ignite scientific discussion, but the videos need an open-access platform where they can be referenced in a topic-related order.

  10. Feeding behaviour of the hydromedusa Aequorea vitrina

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    Hans Ulrik RiisgÅrd

    2007-06-01

    Full Text Available The prey-capture mechanism of the hydromedusa Aequorea vitrina was studied by means of laboratory video-microscope observations. In stagnant water A. vitrina remains stationary with its very long (about 4x bell diameter marginal tentacles motionless hanging down in the water, ready for ambush capture of prey organisms that collide with the tentacles. A. vitrina was found to be efficient at capturing brine shrimps (Artemia salina, less efficient at capturing rotifers (Brachionus plicatilis, and very inefficient at capturing copepods (Acartia tonsa. The initial hauling up of an extended marginal tentacle with an adhering prey is fast (>10 mm s-1. Both the bell margin and the mouth move towards each other so that the captured prey can be transferred from the tentacle to the elongated mouth-lips to be further transported into the mouth and stomach. It takes about 20 s from when an Artemia prey organism encounters a tentacle until it is transferred to the mouth-lips. The subsequent digestion in the stomach takes about 30 min. When A. vitrina encounters a jellyfish-prey (a small medusa of Aurelia aurita, it starts to swim in order to adhere the relatively big prey to its mouth-lips. Then A. vitrina opens its mouth wide to swallow the captured medusa, a process which takes about 15 to 20 min. The subsequent digestion takes 2 to 3 h. Field observations of undisturbed A. vitrina made by snorkelling in the Limfjord (Denmark revealed that the feeding behaviour was similar to that observed in the laboratory in stagnant water. It is concluded that A. vitrina is an ambush-predator, and not a cruising-predatory medusa as previously suggested.

  11. Phycoremediation of landfill leachate with the chlorophyte Chlamydomonas sp. SW15aRL and evaluation of toxicity pre and post treatment.

    Science.gov (United States)

    Paskuliakova, Andrea; McGowan, Ted; Tonry, Steve; Touzet, Nicolas

    2018-01-01

    Landfill leachate treatment is an ongoing challenge in the wastewater management of existing sanitary landfill sites due to the complex nature of leachates and their heavy pollutant load. There is a continuous interest in treatment biotechnologies with expected added benefits for resource recovery; microalgal bioremediation is seen as promising in this regard. Toxicity reduction of landfill leachate subsequent to phycoremediation was investigated in this study. The treatment eventuated from the growth of the ammonia tolerant microalgal strain Chlamydomonas sp. SW15aRL using a N:P ratio adjustment in diluted leachate for facilitating the process. Toxicity tests ranging over a number of trophic levels were applied, including bacterial-yeast (MARA), protistean (microalgae growth inhibition test), crustacean (daphnia, rotifer) and higher plant (monocot, dicot) assays. Ammonia nitrogen in the diluted landfill leachate containing up to 158mgl(-1) NH4(+)-N (60% dilution of the original) was reduced by 83% during the microalgal treatment. Testing prior to remediation indicated the highest toxicity in the crustacean assays Daphnia magna and Brachionus calyciflorus with EC50s at 24h of ~ 35% and 40% leachate dilution, respectively. A major reduction in toxicity was achieved with both bioassays post microalgal treatment with effects well below the EC20s. The microalgae inhibition test on the other hand indicated increased stimulation of growth after treatment as a result of toxicity reduction but also the presence of residual nutrients. Several concurrent processes of both biotic and abiotic natures contributed to pollutant reduction during the treatment. Modifying phosphate dosage especially seems to require further attention. As a by-product of the remediation process, up to 1.2gl(-1) of microalgal biomass was obtained with ~ 18% DW lipid content. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Toxic effect of a marine bacterium on aquatic organisms and its algicidal substances against Phaeocystis globosa.

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    Qiuchan Yang

    Full Text Available Harmful algal blooms have caused enormous damage to the marine ecosystem and the coastal economy in China. In this paper, a bacterial strain B1, which had strong algicidal activity against Phaeocystis globosa, was isolated from the coastal waters of Zhuhai in China. The strain B1 was identified as Bacillus sp. on the basis of 16S rDNA gene sequence and morphological characteristics. To evaluate the ecological safety of the algicidal substances produced by strain B1, their toxic effects on marine organisms were tested. Results showed that there were no adverse effects observed in the growth of Chlorella vulgaris, Chaetoceros muelleri, and Isochrystis galbana after exposure to the algicidal substances at a concentration of 1.0% (v/v for 96 h. The 48h LC50 values for Brachionus plicatilis, Moina mongolica Daday and Paralichthys olivaceus were 5.7, 9.0 and 12.1% (v/v, respectively. Subsequently, the algicidal substances from strain B1 culture were isolated and purified by silica gel column, Sephadex G-15 column and high-performance liquid chromatography. Based on quadrupole time-of-flight mass spectrometry and PeakView Software, the purified substances were identified as prolyl-methionine and hypoxanthine. Algicidal mechanism indicated that prolyl-methionine and hypoxanthine inhibited the growth of P. globosa by disrupting the antioxidant systems. In the acute toxicity assessment using M. mongolica, 24h LC50 values of prolyl-methionine and hypoxanthine were 7.0 and 13.8 g/L, respectively. The active substances produced by strain B1 can be considered as ecologically and environmentally biological agents for controlling harmful algal blooms.

  13. The evolution of sex is favoured during adaptation to new environments.

    Science.gov (United States)

    Becks, Lutz; Agrawal, Aneil F

    2012-01-01

    Both theory and experiments have demonstrated that sex can facilitate adaptation, potentially yielding a group-level advantage to sex. However, it is unclear whether this process can help solve the more difficult problem of the maintenance of sex within populations. Using experimental populations of the facultatively sexual rotifer Brachionus calyciflorus, we show that rates of sex evolve to higher levels during adaptation but then decline as fitness plateaus. To assess the fitness consequences of genetic mixing, we directly compare the fitnesses of sexually and asexually derived genotypes that naturally occur in our experimental populations. Sexually derived genotypes are more fit than asexually derived genotypes when adaptive pressures are strong, but this pattern reverses as the pace of adaptation slows, matching the pattern of evolutionary change in the rate of sex. These fitness assays test the net effect of sex but cannot be used to disentangle whether selection on sex arises because highly sexual lineages become associated with different allele combinations or with different allele frequencies than less sexual lineages (i.e., "short-" or "long-term" effects, respectively). We infer which of these mechanisms provides an advantage to sex by performing additional manipulations to obtain fitness distributions of sexual and asexual progeny arrays from unbiased parents (rather than from naturally occurring, and thereby evolutionarily biased, parents). We find evidence that sex breaks down adaptive gene combinations, resulting in lower average fitness of sexual progeny (i.e., a short-term disadvantage to sex). As predicted by theory, the advantage to sex arises because sexually derived progeny are more variable in fitness, allowing for faster adaptation. This "long-term advantage" builds over multiple generations, eventually resulting in higher fitness of sexual types.

  14. Cultivation of Arthrospira (Spirulina platensis using confectionary wastes for aquaculture feeding

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    Hala Y. El-Kassas

    2015-12-01

    Full Text Available The microalga biomass production from confectionary effluent is a possible solution for the urgent need for a live food in aquaculture. Arthrospira (Spirulina platensis was the dominant alga in effluent of “Biscomisr a confectionary factory”, in Alexandria–Egypt. Therefore, it was isolated from the effluent samples and used throughout the study. The cyanobacterium, A. platensis was grown on the effluent using 22 Central Composite Design (22 CCD. This work addresses the best effluent dilution (WC, % as well as sodium bicarbonate concentration (SBC on the alga growth and biochemical composition. Total protein, carbohydrate, lipid contents and fatty acid profiles of the produced algal biomass were highly improved. The statistical analyses suggested that the main effect of (WC, % is significant negative influences on the algal contents of proteins, lipids and carbohydrates (p > 0.01. Although it had a significant positive influence on chlorophyll (p > 0.01, no significant effect on algal β carotenes (p > 0.05 had been reported. The inter action effect of SBC together with WC, % exerted a significant negative influence on the algal proteins (p > 0.01 and no significant effect on the other responses (p > 0.05. The produced alga biomass was used for feeding the rotifer, Brachionus plicatilis for further application in aquaculture. Growth rate, reproductive rate and fecundity attributes, fatty acid content of B. plicatilis were amended. The Pearson correlation test indicated that β carotenes displayed a highly positive significant correlation with the growth rate of B. plicatilis (r = 0.733, p < 0.01 and the carbohydrates showed significant positive correlations with Egg % (r = 0.657, p < 0.05.

  15. Long-term competitive dynamics of two cryptic rotifer species: diapause and fluctuating conditions.

    Science.gov (United States)

    Gabaldón, Carmen; Carmona, María José; Montero-Pau, Javier; Serra, Manuel

    2015-01-01

    Life-history traits may have an important role in promoting species coexistence. However, the complexity of certain life cycles makes it difficult to draw conclusions about the conditions for coexistence or exclusion based on the study of short-term competitive dynamics. Brachionus plicatilis and B. manjavacasare two cryptic rotifer species co-occurring in many lakes on the Iberian Peninsula. They have a complex life cycle in which cyclical parthenogenesis occurs with diapausing stages being the result of sexual reproduction. B. plicatilis and B. manjavacasare identical in morphology and size, their biotic niches are broadly overlapping, and they have similar competitive abilities. However, the species differ in life-history traits involving sexual reproduction and diapause, and respond differently to salinity and temperature. As in the case of certain other species that are extremely similar in morphology, a fluctuating environment are considered to be important for their coexistence. We studied the long-term competitive dynamics of B. plicatilis and B. manjavacas under different salinity regimes (constant and fluctuating). Moreover, we focused on the dynamics of the diapausing egg bank to explore how the outcome of the entire life cycle of these rotifers can work to mediate stable coexistence. We demonstrated that these species do not coexist under constant-salinity environment, as the outcome of competition is affected by the level of salinity-at low salinity, B. plicatilis excluded B. manjavacas, and the opposite outcome occurred at high salinity. Competitive dynamics under fluctuating salinity showed that the dominance of one species over the other also tended to fluctuate. The duration of co-occurrence of these species was favoured by salinity fluctuation and perhaps by the existence of a diapausing egg bank. Stable coexistence was not found in our system, which suggests that other factors or other salinity fluctuation patterns might act as stabilizing

  16. Effect of food type and concentration on growth and fatty acid composition of early larvae of the anchovy (Engraulis encrasicolus) reared under laboratory conditions

    KAUST Repository

    Garrido, Susana

    2012-12-01

    Experiments were conducted during the summer of 2008 and 2009 to study the growth of early post yolk-sac European anchovy (Engraulis encrasicolus, Linnaeus, 1758) larvae reared under different food regimes. The fatty acid composition was used to assess nutritional condition of the larvae. Prey items used in the experiments were Gymnodinium sanguineum, Brachionus plicatilis and nauplii of the copepods Acartia grani and Euterpina acutifrons. Food type and concentration affected the growth of the larvae. Mixed diets composed of rotifers and copepod nauplii at high concentration resulted in higher anchovy larvae growth rates in comparison with single-prey diets using either rotifers or copepod nauplii. The addition of the dinoflagellate G. sanguineum (25-50cellsml -1) to the prey offered did not enhance significantly larval growth. Highest growth rates of anchovy larvae (0.28mmd -1) were obtained using high concentrations of a mixed diet, particularly the combination of rotifers and A. grani nauplii. Fatty acid composition at hatch was similar to the composition observed in the field, but during larvae ontogeny there was a marked decrease in the contribution of polyunsaturated fatty acids such as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). Such difference reflects the high requirements of these PUFA for larvae development, and suggests that the food offered failed to fulfill the larvae nutritional requirements. The growth rates obtained in our experiments were, overall, in the lower range of those observed in natural conditions. Taking into considerations the fact that larvae in the field are expected to encounter lower prey concentrations, we discuss the reasons for such disagreement. © 2012 Elsevier B.V.

  17. Application of leaching tests for toxicity evaluation of coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Tsiridis, V.; Samaras, P.; Kungolos, A.; Sakellaropoullos, G.P. [Technological Educational Institute for West Macedonia, Kozani (Greece). Dept. for Pollution Control Technology

    2006-08-15

    The toxic properties of coal fly ash samples obtained from various coal combustion power plants were evaluated in this work using physicochemical analyses and bioassays. Physicochemical analyses showed that heavy metals present in solid samples included Cr, Cu, Mn, Ni, Pb, and Zn. The results of the chemical analysis of eluates deduced by the application of standard leaching tests according to EN 12457-2 and Toxicity Characteristic Leaching Procedure (TCLP) methods indicated that the compounds contained in fly ashes could potentially be transferred to the liquid phase depending upon the leaching method used. Heavy metal concentrations were higher in TCLP eluates, indicating that the initial pH value of the leaching medium significantly affected the transfer of these elements to the liquid phase. Tests conducted with the photobacterium Vibrio fischeri (Microtox test), the crustacean Daphnia magna, and the rotifer Brachionus calyciflorus were used to assess toxicity of eluates obtained by both leaching tests. Daphnia magna was the most sensitive test organism. The EN 12457-2 method proved to be more reliable for toxicity evaluation of eluates. In contrast, the TCLP method showed some interference owing to acetic acid toxicity, and precipitation occurred after pH adjustment of eluates from acid to neutral range. The toxicity of both fly ashes and the corresponding solid leaching residues of EN 12457-2 and TCLP leaching tests was also measured using the Microtox Basic Solid phase Test. The results generated with this bioassay indicated that toxicity was greatly influenced by the pH status of the solid samples.

  18. First feed affects the expressions of microRNA and their targets in Atlantic cod.

    Science.gov (United States)

    Bizuayehu, Teshome Tilahun; Furmanek, Tomasz; Karlsen, Ørjan; van der Meeren, Terje; Edvardsen, Rolf Brudvik; Rønnestad, Ivar; Hamre, Kristin; Johansen, Steinar D; Babiak, Igor

    2016-04-14

    To our knowledge, there is no report on microRNA (miRNA) expression and their target analysis in relation to the type of the first feed and its effect on the further growth of fish. Atlantic cod (Gadus morhua) larvae have better growth and development performance when fed natural zooplankton as a start-feed, as compared with those fed typical aquaculture start-feeds. In our experiment, two groups of Atlantic cod larvae were fed reference feed (zooplankton, mostly copepods, filtered from a seawater pond) v. aquaculture feeds: enriched rotifers (Brachionus sp.) and later brine shrimp (Artemia salina). We examined the miRNA expressions of six defined developmental stages as determined and standardised by body length from first feeding for both diet groups. We found eight miRNA (miR-9, miR-19a, miR-130b, miR-146, miR-181a, miR-192, miR-206 and miR-11240) differentially expressed between the two feeding groups in at least one developmental stage. We verified the next-generation sequencing data using real-time RT-PCR. We found 397 putative targets (mRNA) to the differentially expressed miRNA; eighteen of these mRNA showed differential expression in at least one stage. The patterns of differentially expressed miRNA and their putative target mRNA were mostly inverse, but sometimes also concurrent. The predicted miRNA targets were involved in different pathways, including metabolic, phototransduction and signalling pathways. The results of this study provide new nutrigenomic information on the potential role of miRNA in mediating nutritional effects on growth during the start-feeding period in fish larvae.

  19. Performance of Debaryomyces hansenii as a Diet for Rotifers for Feeding Zebrafish Larvae.

    Science.gov (United States)

    Opazo, Rafael; Fuenzalida, Karen; Plaza-Parrochia, Francisca; Romero, Jaime

    2017-04-01

    The zebrafish larval stage is a critical moment due to high mortality rates associated with inadequate supplies of nutritional requirements. Larval feeding has important challenges associated with such factors as small mouth gape (≈100 μm), the low activity of digestive enzymes, and the intake of live food. A common zebrafish live food at the onset of exogenous feeding is rotifers, mainly Brachionus plicatilis. These rotifers should be fed with other microorganisms such as microalgae or yeast, mostly from the Saccharomyces genus. In the laboratory, the culture of microalgae is more expensive than the culture of yeast. The aim of this study was to evaluate the performance of Debaryomyces hansenii as a diet for rotifers in comparison to a microalgae-based diet (Rotigrow®). To achieve this aim, we assessed the rotifer total protein content, the rotifers fatty acid profile, zebrafish larval growth performance, the expression of key growth, and endocrine appetite regulation genes. The total protein and fatty acids content were similar in both rotifer cultures, averaging 35% of dry matter (DM) and 18% of DM, respectively. Interestingly, the fatty acids profile showed differences between the two rotifer cultures: omega-3 fatty acids were only observed in the Microalgae/rotifer, whereas, omega-6 fatty acids presented similar levels in both rotifer cultures. No differences were observed in the larval body length distribution or mortalities between the rotifer cultures. However, gh, igf-1, and cck gene expression showed significantly higher upregulation in zebrafish fed the Microalgae/rotifer diet compared with those fed the Debaryomyces/rotifer diet. In conclusion, D. hansenii could be an alternative diet for rotifer used as a live food in zebrafish larvae at the onset of exogenous feeding. The gene responses observed in this work open up the opportunity to study the effect of omega-3 supply on growth regulation in zebrafish.

  20. Assessing the impacts of dimethoate on rotifers' reproduction through the pre-exposure history.

    Science.gov (United States)

    Guo, Ruixin; Chen, Jianqiu

    2015-01-01

    Organism usually undergoes an exposure of environmental pollution after a maternal exposure before birth. Traditional toxicological studies often initiated with rotifer neonates derived from the unexposed mothers while ignoring the pre-exposure (maternal exposure). The present study assessed the effect of dimethoate on the reproduction of the rotifer Brachionus calyciflorus, considering how the pre-exposure occurred in the parental generation influenced the subsequent impact. The F0 generation rotifers were exposed to the pesticide at five concentrations until the first F1 generation rotifers were reproduced. The neonates (F1 generation) were then exposed to the pesticide at the corresponding concentrations. The offspring reproduction, the time begins to reproduce, the duration of the reproductive period and the lifespan of the F1 generation rotifers were evaluated. Our results indicated that dimethoate influenced the maturation and reproduction of the rotifers. The highest concentration (1.8 mg L(-1)) of dimethoate caused an inhibition in the offspring reproduction, shortened the life span and reduced the duration of the reproductive period. In addition, of particular interest in our study was that reproduction is also accelerated by the lowest concentration (0.2 mg L(-1)). However, the pre-exposure had a significant effect on the subsequent impact. The dimethoate pre-exposure increased the impacts when the F1 generation rotifers were exposed to the substance, even at the same concentrations as in pre-exposure. It suggests that the maternal exposure history before birth is also important and has the long-lasting consequence from one generation to another. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Environmental

    Directory of Open Access Journals (Sweden)

    Sawsan M. Aboul Ezz

    2014-01-01

    Full Text Available Rotifers are one of the most common, abundant components of plankton in the coastal waters of the Mediterranean Sea, which means that they can be used as bio-indicators and provide useful information on the long-term dynamics of the El-Mex Bay ecosystem. Rotifera species were quantitatively and qualitatively assessed in the El-Mex Bay, west of Alexandria at eight stations to study spatial, temporal, dominance, and abundance of the rotifer community and their relation with changes in environmental conditions. Samples were collected seasonally from autumn 2011 to autumn 2012. Ecological parameters were determined and correlated with total rotifers abundance to gain information about the forces that structure the rotifer community in this dynamic environment. A total of 38 rotifer species were identified belonging to 16 genera within 12 families and 3 orders under one class and contributed about 12.1% of the total zooplankton in the study area with an average of 1077 specimens/m3. Maximum density was observed in summer 2012 with an average of 1445 specimens/m3. During autumn 2011 rotifers appeared in low density (434 specimens/m3. The predominant species Ascomorpha saltans, Brachionus urceolaris, Synchaeta oblonga, Synchaeta okai, Synchaeta pectinata and Synchaeta tremula were recorded in all study stations of the bay. Salinity, temperature, depth, and chlorophyll-a concentration were the most important environmental factors co-related with the abundance of rotifers in the El-Mex Bay. A significant positive correlation between the total rotifer abundance and chlorophyll-a was observed during winter 2012 and summer 2012 (r = 0.763 and r = 0.694, respectively, at p ⩽ 0.05.

  2. Enriching rotifers with "premium" microalgae. Nannochloropsis gaditana.

    Science.gov (United States)

    Ferreira, Martiña; Coutinho, Paula; Seixas, Pedro; Fábregas, Jaime; Otero, Ana

    2009-01-01

    The nutritive quality of Nannochloropsis gaditana cultured semicontinuously with different daily renewal rates was tested as a diet for short-term enrichment of the rotifer Brachionus plicatilis. After 24 h, dramatic differences in the survival, dry weight, and biochemical composition of the rotifers depending on the renewal rate of microalgal cultures were observed. Survival after the feeding period increased with increasing renewal rates. Rotifers fed microalgae from low renewal rate, nutrient-deficient cultures showed low dry weight and organic contents very similar to those of the initial rotifers that were starved for 12 h before the start of the feeding period. On the contrary, rotifers fed nutrient-sufficient microalgal cells underwent up to twofold increases of dry weight and protein, lipid, and carbohydrate contents with regard to rotifers fed nutrient-depleted N. gaditana. Consequently, feed conversion rate decreased in these conditions, indicating a better assimilation of the microalgal biomass obtained at high renewal rates. No single microalgal biochemical parameter among those studied can explain the response of the filter feeder. Similarly to gross composition, EPA and n-3 contents in rotifers fed microalgae from nutrient-sufficient cultures were double than the contents found in rotifers fed nutrient-limited microalgae. In addition, very high positive correlations between the contents of EPA and n-3 in N. gaditana and B. plicatilis were observed. These results demonstrate that selecting the appropriate conditions of semicontinuous culture can strongly enhance the nutritional value of microalgae that is reflected in the growth and biochemical composition of the filter-feeder even in short exposure periods.

  3. Does Haplodiploidy Purge Inbreeding Depression in Rotifer Populations?

    Science.gov (United States)

    Tortajada, Ana M.; Carmona, María José; Serra, Manuel

    2009-01-01

    Background Inbreeding depression is an important evolutionary factor, particularly when new habitats are colonized by few individuals. Then, inbreeding depression by drift could favour the establishment of later immigrants because their hybrid offspring would enjoy higher fitness. Rotifers are the only major zooplanktonic group where information on inbreeding depression is still critically scarce, despite the fact that in cyclical parthenogenetic rotifers males are haploid and could purge deleterious recessive alleles, thereby decreasing inbreeding depression. Methodology/Principal Findings We studied the effects of inbreeding in two populations of the cyclical parthenogenetic rotifer Brachionus plicatilis. For each population, we compared both the parental fertilization proportion and F1 fitness components from intraclonal (selfed) and interclonal (outcrossed) crosses. The parental fertilization proportion was similar for both types of crosses, suggesting that there is no mechanism to avoid selfing. In the F1 generation of both populations, we found evidence of inbreeding depression for the fitness components associated with asexual reproduction; whereas inbreeding depression was only found for one of the two sexual reproduction fitness components measured. Conclusions/Significance Our results show that rotifers, like other major zooplanktonic groups, can be affected by inbreeding depression in different stages of their life cycle. These results suggest that haplodiploidy does not purge efficiently deleterious recessive alleles. The inbreeding depression detected here has important implications when a rotifer population is founded and intraclonal crossing is likely to occur. Thus, during the foundation of new populations inbreeding depression may provide opportunities for new immigrants, increasing gene flow between populations, and affecting genetic differentiation. PMID:19997616

  4. Phaeobacter gallaeciensis reduces Vibrio anguillarum in cultures of microalgae and rotifers, and prevents vibriosis in cod larvae.

    Science.gov (United States)

    D'Alvise, Paul W; Lillebø, Siril; Prol-Garcia, Maria J; Wergeland, Heidrun I; Nielsen, Kristian F; Bergh, Øivind; Gram, Lone

    2012-01-01

    Phaeobacter gallaeciensis can antagonize fish-pathogenic bacteria in vitro, and the purpose of this study was to evaluate the organism as a probiont for marine fish larvae and their feed cultures. An in vivo mechanism of action of the antagonistic probiotic bacterium is suggested using a non-antagonistic mutant. P. gallaeciensis was readily established in axenic cultures of the two microalgae Tetraselmis suecica and Nannochloropsis oculata, and of the rotifer Brachionus plicatilis. P. gallaeciensis reached densities of 10(7) cfu/ml and did not adversely affect growth of algae or rotifers. Vibrio anguillarum was significantly reduced by wild-type P. gallaeciensis, when introduced into these cultures. A P. gallaeciensis mutant that did not produce the antibacterial compound tropodithietic acid (TDA) did not reduce V. anguillarum numbers, suggesting that production of the antibacterial compound is important for the antagonistic properties of P. gallaeciensis. The ability of P. gallaeciensis to protect fish larvae from vibriosis was determined in a bath challenge experiment using a multidish system with 1 larva per well. Unchallenged larvae reached 40% accumulated mortality which increased to 100% when infected with V. anguillarum. P. gallaeciensis reduced the mortality of challenged cod larvae (Gadus morhua) to 10%, significantly below the levels of both the challenged and the unchallenged larvae. The TDA mutant reduced mortality of the cod larvae in some of the replicates, although to a much lesser extent than the wild type. It is concluded that P. gallaeciensis is a promising probiont in marine larviculture and that TDA production likely contributes to its probiotic effect.

  5. Phaeobacter gallaeciensis reduces Vibrio anguillarum in cultures of microalgae and rotifers, and prevents vibriosis in cod larvae.

    Directory of Open Access Journals (Sweden)

    Paul W D'Alvise

    Full Text Available Phaeobacter gallaeciensis can antagonize fish-pathogenic bacteria in vitro, and the purpose of this study was to evaluate the organism as a probiont for marine fish larvae and their feed cultures. An in vivo mechanism of action of the antagonistic probiotic bacterium is suggested using a non-antagonistic mutant. P. gallaeciensis was readily established in axenic cultures of the two microalgae Tetraselmis suecica and Nannochloropsis oculata, and of the rotifer Brachionus plicatilis. P. gallaeciensis reached densities of 10(7 cfu/ml and did not adversely affect growth of algae or rotifers. Vibrio anguillarum was significantly reduced by wild-type P. gallaeciensis, when introduced into these cultures. A P. gallaeciensis mutant that did not produce the antibacterial compound tropodithietic acid (TDA did not reduce V. anguillarum numbers, suggesting that production of the antibacterial compound is important for the antagonistic properties of P. gallaeciensis. The ability of P. gallaeciensis to protect fish larvae from vibriosis was determined in a bath challenge experiment using a multidish system with 1 larva per well. Unchallenged larvae reached 40% accumulated mortality which increased to 100% when infected with V. anguillarum. P. gallaeciensis reduced the mortality of challenged cod larvae (Gadus morhua to 10%, significantly below the levels of both the challenged and the unchallenged larvae. The TDA mutant reduced mortality of the cod larvae in some of the replicates, although to a much lesser extent than the wild type. It is concluded that P. gallaeciensis is a promising probiont in marine larviculture and that TDA production likely contributes to its probiotic effect.

  6. Does copepods influence dusky grouper (Epinephelus marginatus early development?

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    Monica Mateus

    2014-06-01

    Full Text Available Good knowledge on the development of early life stages is essential for successful conservation programs of threatened fish species. Diet and rearing system affects early life survival and juvenile quality. Copepods are the natural food of fish larvae in the wild possessing high nutritional value, when compared with live feeds used in aquaculture (rotifers and artemia, and a wide range of size classes. Rearing systems with low water column disturbance and low larval densities enhanced the survival of fragile fish larvae. The aim of this work is to evaluate the effect of the introduction of copepods in the diet of early dusky grouper larvae reared in controlled mesocosm systems using larval development and juvenile quality as indicators. Two feeding protocols were tested, one composed only by rotifers (Brachionus plicatilis, brine shrimp (Artemia spp. and dry feed and the other supplemented with copepods (Paracartia grani from mouth opening (2 day after hatching - DAH to 8 DAH. Feeding behavior, growth, survival, skeletal malformations and digestive enzymes activity was assessed at different developmental stages. The addition of copepods to the early larvae diet of dusky grouper resulted in faster development and higher survival rates. Larvae fed with copepods improved their development. At 20 DAH all larvae reared at the mesocosm with copedods were already at the stage of post-flexion while in the system without copepods this stage was attained later. At 25 DAH only 64% of the larvae were in post flexion in the mesoscosm without copepods. At 30 DAH larvae supplemented with copepods attained an acidic digestion (high specific activity of pepsin earlier than at the system without copepods. In this last system alkaline digestion (trypsin specific activity, characteristic of early larval stages, was significantly higher reinforcing the faster development of larvae fed with copepods. In both systems the incidence of skeletal malformations was low.

  7. EFECTOS DE LA FLUCTUACIÓN DEL NIVEL DEL AGUA SOBRE LA ESTRUCTURA DEL ENSAMBLAJE DE ROTÍFEROS EN EL LAGO LARGO (SISTEMA YAHUARCACA - LLANURA DE INUNDACIÓN DEL RÍO AMAZONAS - COLOMBIA

    Directory of Open Access Journals (Sweden)

    Andrade Camilo

    2011-12-01

    Full Text Available Se realizó un reconocimiento taxonómico y estimación de la densidad en el ensamblaje de rotíferos en el lago Largo, del sistema de lagos Yahuarcaca, en la ribera colombiana del río Amazonas, a partir de muestreos en las fases hidrológicas de aguas bajas, ascenso y descenso. Se identificaron 68 especies, 28 de ellas son nuevos registros para ambientes colombianos. Se encontró aumento en la riqueza en las épocas de ascenso y descenso, siendo mayor en la zona litoral respecto de la limnética, y la tendencia a mayor similitud taxonómica entre ambas zonas en el periodo de aguas bajas, debido al mínimo desarrollo de macrófitas en esta fase y la consecuente menor heterogeneidad espacial. Se observó el predominio de rotíferos con trofi adaptados para moler y triturar partículas (maleado y maleorramado en las épocas de aguas bajas (Brachionus ahlstromi y descenso (Filina saltator y en la época de ascenso de Polyarthra vulgaris, con trofi adaptado para perforar y succionar fluidos de algas y otros organismos (virgado y apéndices que favorecen la rápida natación. En general, se establecieron posibles relaciones entre la riqueza y la densidad de rotíferos con cambios en características como el desarrollo de vegetación acuática en el litoral, profundidad del lago, nivel de conectividad con los otros lagos del sistema Yahuarcaca, influencia de aguas blancas del Amazonas y negras de origen local, potenciales recursos nutricionales y depredadores, y posible efecto de arrastre por la corriente.

  8. Species composition, abundance and distribution of zooplankton in a tropical eutrophic lake: Lake Catemaco, México

    Directory of Open Access Journals (Sweden)

    Roberto E. Torres-Orozco B.

    1998-06-01

    Full Text Available From April 1992 to May 1993, zooplankton samples were collected monthly by means of horizontal tows in nine sites of the lake. Prior to the towing, temperature of surface water, transparency (Secchi, pH and dissolved oxygen were evaluated. A total of 31 zooplankton forms, including 14 species of rotifers, three copepods, five cladocerans and one ostracod, as well as protozoans (mainly vorticellids and ciliates, were detected. Rotifers were the dominant organisms, mainly Brachionus havanaensis (27.6 ind l-¹, B. angularis (6.9 ind l-¹, Keratella cochlearis (4.9 ind l-¹, Conochilus unicornis (10.8 ind l-¹ and C. dossuarius (3.1 ind l-¹. Within crustaceans, higher densities were shown by larvae (nauplii and copepodites of calanoid (16.8 ind l-¹ and cyclopoid (15.6 ind l-¹ copepods, as well as Arctodiaptomus dorsalis (2 ind l-¹, Mesocyclops edax (0.5 ind l-¹, and the cladocerans Bosmina longirostris (1.6 ind l-¹ and Diaphanosoma brachyurum (0.5 ind l-¹. Densities were low, probably because of a high predation pressure imposed by fishes. A gradual increase in total zooplankton density related with a progressive diminution of transparency was observed throughout the sampling period. Zooplankton densities in the stations located at the central part of the lake were higher when compared with those at a more peripheral position. Time variation in rotifer's relative abundance was directly related to temperature fluctuations. The low density and diversity values, the small size of the zooplankters, the presence of an important number of indicator species, and the calanoid copepods: other planktonic crustaceans low ratio, are all indicators of eutrophy. Evidences suggest that the eutrophication process of Lake Catemaco is still progressing rapidly.Entre abril de 1992 y mayo de 1993, se realizaron mensualmente recolectas subsuperficiales de zooplancton, con red, en nueve localidades del lago, en donde también se determinaron la temperatura

  9. Plancto e hidrobiologia sanitária de tanques tropicais com dáfnias e rotíferos

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    Lejeune P. H. de Oliveira

    1967-01-01

    NH[4 subscripted]. b Species of the genus Chlamydomonas; it is even possible that all the species of theses genus inhabit strong-mesosaprobic to polysaprobic waters when in massive blooms. c Several species of Euglenaceae in fast growing number, at the same time of the protozoa Amoebidae, Vorticellidae and simultaneous with deposition of the decaying cells of the blue algae Anacystis cyanea (= Microcystis when the consumed oxygen by organic matter resulted in 40 mg. L. But, we found, among various Euglenacea the cosmopolite species (Euglena viridis, a well known polysaprobic indicatior of which presence occur in septic zone. d Analcystis cyanea (= M. aeruginosa as we observed was in blooms increasing to the order of billions of cells per litter, its maximum in the summer. Temperatures 73ºF to 82ºF but even 90ºF, the pH higher than 8. When these blue algae was joined to the rotifer Brachionus calyflorus the waters gets a milky appearance, but greenished one. In fact, that cosmopolite algae is used as a mesosaprobic indicator. Into the water of the ponds its predominance finished when the septic polysaprobic conditions began. e Ankistrodesmus falcatus was present in the 5th pond from 26the. April untill the 26th July, and when N.NH[4 subscripted] gets 1.28 mg. L. and when chlorinity stayed from 0.034 to 0.061 mg. L. It never was found at N.NH[4 subscripted] higher than 1 mg. L. The green algae A. falcatus, an indicatior of pollution, lives in moderate mesosaprobic waters. f As everyone knows, the rotifer eggs may be widely dispersed by wind. The rotifer Asplanchna brightwelli in our observation seemed like a green colored bag, overcharged by green cells and detritus, specially into its spacious stomach, which ends blindly (the intestine, cloaca, being absent. The stock of Asplanchna in the ponds, during the construction of the bridge "PONTE OSWALDO CRUZ" inhabits alkaline waters, pH 8,0 a 8,3, and when we observed we noted its dissolved oxygen from 3.5 to 4 mg. L

  10. The chronic toxicity of molybdate to freshwater organisms. I. Generating reliable effects data

    Energy Technology Data Exchange (ETDEWEB)

    De Schamphelaere, K.A.C., E-mail: karel.deschamphelaere@Ugent.be [Laboratory of Environmental Toxicology and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University (Belgium); Stubblefield, W. [Oregon State University, Department of Environmental and Molecular Toxicology, 421 Weniger Hall, Corvallis, OR 97331 (United States); Rodriguez, P. [Centro de Investigacion Minera y Metalurgica (CIMM), Santiago (Chile); Vleminckx, K. [Department for Molecular Biomedical Research, Ghent University (Belgium); Janssen, C.R. [Laboratory of Environmental Toxicology and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University (Belgium)

    2010-10-15

    The European Union regulation on Registration, Evaluation, Authorization and Restriction of Chemical substances (REACH) (EC, 2006) requires the characterization of the chronic toxicity of many chemicals in the aquatic environment, including molybdate (MoO{sub 4}{sup 2-}). Our literature review on the ecotoxicity of molybdate revealed that a limited amount of reliable chronic no observed effect concentrations (NOECs) for the derivation of a predicted no-effect concentration (PNEC) existed. This paper presents the results of additional ecotoxicity experiments that were conducted in order to fulfill the requirements for the derivation of a PNEC by means of the scientifically most robust species sensitivity distribution (SSD) approach (also called the statistical extrapolation approach). Ten test species were chronically exposed to molybdate (added as sodium molybdate dihydrate, Na{sub 2}MoO{sub 4}.2H{sub 2}O) according to internationally accepted standard testing guidelines or equivalent. The 10% effective concentrations (EC10, expressed as measured dissolved molybdenum) for the most sensitive endpoint per species were 62.8-105.6 (mg Mo)/L for Daphnia magna (21 day-reproduction), 78.2 (mg Mo)/L for Ceriodaphnia dubia (7 day-reproduction), 61.2-366.2 (mg Mo)/L for the green alga Pseudokirchneriella subcapitata (72 h-growth rate), 193.6 (mg Mo)/L for the rotifer Brachionus calyciflorus (48 h-population growth rate), 121.4 (mg Mo)/L for the midge Chironomus riparius (14 day-growth), 211.3 (mg Mo)/L for the snail Lymnaea stagnalis (28 day-growth rate), 115.9 (mg Mo)/L for the frog Xenopus laevis (4 day-larval development), 241.5 (mg Mo)/L for the higher plant Lemna minor (7 day-growth rate), 39.3 (mg Mo)/L for the fathead minnow Pimephales promelas (34 day-dry weight/biomass), and 43.2 (mg Mo)/L for the rainbow trout Oncorhynchus mykiss (78 day-biomass). These effect concentrations are in line with the few reliable data currently available in the open literature. The data

  11. Limnological studies on inorganic acid lakes in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Satake, K.

    1980-01-01

    Many volcanic acid lakes having pH from 0.9 to 5.5 are distributed throughout Japan. Most of the lakes with pH less than 4.0 are found in craters of volcanoes, and their acidity depends on an inflow of acidic water from the lake bottom. Many of the remaining lakes are located in caldelas or have a volcanic dammed origin, and their acidity depends on an inflow of acidic river water. Studies on inorganic acid lakes in Japan were initiated in 1915. Next came the limnological works on the Goshikinuma lake group (pH 3.1-7.2) and Lake Katanuma. The typology of acid lakes was discussed by Ueno who observed the lakes located at North Shinano, South Kyushu and the Kuril islands. The biota in acid lakes were studied by Negoro, Kikuchi, Kokubo, Fujimatsu, Tamura and Masiko et al. The researchers reported Pinnularia braunii var. amphicephala in Lake Katanuma (pH 1.4 at that time), Brachionus urceoralis in Lake Ichibishinaiko (pH 2.8), Leptodictyum sp. and fish in Lake Osoresanko (pH 3.4), as well as the other algae, zooplankton and insects in the acid lakes. The deposition of iron compounds was followed by the occurrence of Pinnularia braunii var. amphicephala. After World War II, observation of biota in acid lakes was commenced by Suzuki who reported on the mold and bacteria in acid lakes. Phytoplankton and zooplankton were observed by Mizuno on the lake Group located in Kirishima volcano (pH 3.7-7.5), and Watanabe and Oyagi observed benthic diatoms in Lake Fudoike. Macrophytes and fish were observed by Yamamoto et al., in Lake Osoresanko. In Lake Katanuma Satake and Saijo clarified the mechanism of sulfur-diatom lamination in the sediment. Sato observed the change of biota caused by the acidification of Lake Tazawako. Eguchi et al., observed the inflow of acid river and the change of biota in Lake Toyako. 81 references.

  12. Effects of population outcrossing on rotifer fitness

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    Serra Manuel

    2010-10-01

    Full Text Available Abstract Background Outcrossing between populations can exert either positive or negative effects on offspring fitness. Cyclically parthenogenetic rotifers, like other continental zooplankters, show high genetic differentiation despite their high potential for passive dispersal. Within this context, the effects of outcrossing may be relevant in modulating gene flow between populations through selection for or against interpopulation hybrids. Nevertheless, these effects remain practically unexplored in rotifers. Here, the consequences of outcrossing on the rotifer Brachionus plicatilis were investigated. Cross-mating experiments were performed between a reference population and three alternative populations that differed in their genetic distance with regard to the former. Two offspring generations were obtained: F1 and BC ('backcross'. Fitness of the outcrossed offspring was compared with fitness of the offspring of the reference population for both generations and for three different between-population combinations. Four fitness components were measured throughout the rotifer life cycle: the diapausing egg-hatching proportion, clone viability (for the clones originating from diapausing eggs, initial net growth rate R for each viable clone, and the proportion of male-producing clones. Additionally, both the parental fertilisation proportion and a compound fitness measure, integrating the complete life cycle, were estimated. Results In the F1 generation, hybrid vigour was detected for the diapausing egg-hatching proportion, while R was lower in the outcrossed offspring than in the offspring of the reference population. Despite these contrasting results, hybrid vigour was globally observed for the compound measure of fitness. Moreover, there was evidence that this vigour could increase with the genetic differentiation of the outcrossed populations. In the BC generation, the hybrid vigour detected for the egg-hatching proportion in the F1

  13. Direct and Indirect Effects of Resource P-Limitation Differentially Impact Population Growth, Life History and Body Elemental Composition of a Zooplankton Consumer

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    Libin Zhou

    2018-02-01

    Full Text Available One of the central tenets of ecological stoichiometry is that consumer growth rate is strongly determined by food phosphorus (P content. In planktonic organisms population growth rates of zooplankton have repeatedly been shown to be reduced when fed with P-limited algal food sources. However, P-limitation may also affect other quality-related aspects of algae, such as biochemical composition or palatability. We studied the population growth, detailed life history and body elemental composition of the herbivorous rotifer, Brachionus calyciflorus, in response to three different food quality treatments: algae cultured in high phosphorus conditions (average algal molar C:P ≈ 112, ‘HP’, algae cultured in low P conditions (molar C:P ≈ 631, ‘LP’ and low-P cultured algae spiked with P just before feeding (molar C:P ≈ 113, ‘LP+P’. LP+P algae thus combined high P content with a history of growth under P-limited conditions. Total P content and the C:P ratio of rotifers in the LP+P treatment equaled those of rotifers in the HP treatment. Rotifer population growth rates were higher in HP than in LP and intermediate in the LP+P treatment. Similarly, many life history traits observed for animals in the LP+P treatment, such as somatic growth rate, age at maturity, and egg production rate were also intermediate to those observed in the LP and HP treatments. However, there were important deviations from this pattern: size at first reproduction and egg mortality in the LP+P treatment equaled the HP treatment, whereas size and development time of the first eggs equaled those of the LP treatment. Our results indicate that elemental limitation cannot fully explain reduced performance of consumers fed with P-limited algae and strongly suggest that indirect, non-stoichiometric effects of P-limitation, e.g., via changes in biochemical composition or morphology of the algae also play a major role. Furthermore, our study highlights that such indirect

  14. G. J. Billberg's (1833) 'On the ichthyology, and description of some new fish species of the pipefish genus Syngnathus'.

    Science.gov (United States)

    Kullander, Sven O

    2016-01-14

    Gustaf Johan Billberg's review of ichthyology, published in Swedish in 1833 in the Linnéska samfundets handlingar, mentions 92 fish taxa at genus and species level, 41 of which represent new taxa, unnecessary replacement names, or unjustified emendations. Billberg presents his own classification of fishes, in which five new family names are introduced: Ballistidae, Diodontidae, Ooididae, Chironectidae, and Macrorhyncidae. Diodontidae has priority over Diodontidae Bonaparte, 1835. Macrorhyncidae was published earlier than Gempylidae Gill, 1862, but the latter has priority by prevailing usage.        Billberg mentions 61 genera of fishes, 41 of them listed only by name. Six generic names proposed by Billberg are available as unjustified emendations: Myxinus, Petromyzus, Scylia, Mustellus, Zyganna, and Ballistes. Brachionus is an unnecessary replacement name. Aphrus, Capriscus, Exormizus, Enneophthalmus, and Oedaus are nomina nuda. Eight new genera of fishes are proposed: Anodon, Posthias, Orbis, Sphaeroides, and Ooides are junior synonyms; Cotilla is a nomen oblitum in relation to Sufflamen Jordan, 1916; Tropigaster a nomen oblitum in relation to Aracana Gray, 1835; and Tetragonizus a nomen oblitum in relation to Lactoria Jordan & Fowler, 1902.        Billberg lists 31 species of fishes. Three represent new combinations; two are nomina nuda. The following 14 new species are described based on literature: Raja forskohlii, Cephaloptera dumerillii, Myliobatis lacepedei, Scylia russelii, Anodon macropterus, Cotilla frenata, Monacanthus blochii, M. sebae, M. cuvieri, M. marcgravii, Tetraodon striatus, Orbis psittacinus, Orbis punctulatus, and Orbis guttatus. All of those are invalid, except Scylia russelii, which is a species inquirenda. The following nine species group names are unnecessary replacement names and consequently invalid: Raja arabica, Myliobatis rissoi, Scylia isabellina, Anodon cirrhosus, Anodon cornutus, Zyganna voracissima, Centrina

  15. Development of fingerlings of Piracanjuba (Brycon orbignyannus, Vallencienes (1849 (Teleostei: characidae in tanks fertilized with organic manures/ Desenvolvimento de juvenis de Piracanjuba (Brycon orbignyannus, Vallencienes (1849 (Teleostei: characidae em tanques experimentais fertilizados com adubação orgânica

    Directory of Open Access Journals (Sweden)

    Carmino Hayashi

    2005-06-01

    Full Text Available The objective of this paper was to study the development of Piracanjuba (Brycon orbignyanus in tanks under differents organic fertilizers. The experiment, entirely randomized, was accomplished in 16 tanks of 1000 liters, fertilized with manures of bovine (BOV, pigs (SUI, chickens (FRG and others without fertilizer (SAO, using 15 fish/m3 with an initial average weight and length of 10,87+0,31 g e 9,78+0,07 cm. After 30 days, the experiment showed a uniform development of the fish and high survival rate in thestudied density. The treatments presented significant statistical differences (PO objetivo deste trabalho foi estudar o desenvolvimento de juvenis de Piracanjuba (Brycon orbignyanus, em tanques com adubações orgânicas. O experimento, inteiramente casualizado, foi realizado em 16 tanques de 1000 litros, adubados com estercos de bovinos (BOV, suínos (SUI, frangos de corte (FRG e outros sem adubação (SAO, utilizando 15 peixes/m3 com peso e comprimento médios iniciais de 10,87+0,31 g e 9,78+0,07 cm. Após 30 dias, o experimento mostrou um desenvolvimento uniforme dos peixes e alta taxa de sobrevivência na densidade estudada. Os tratamentos apresentaram diferenças estatisticamente significativas (p < 0,05 para ganho de peso e crescimento diário, com exceção dos tratamentos BOV e SUI quando comparados entre si. A temperatura e o oxigênio dissolvido foram os fatores abióticos que exerceram maior influência sobre a biota aquática, afetando o desenvolvimento dos peixes. Entre o fitoplâncton houve maior abundância de organismos nanoplanctônicos favorecendo o desenvolvimento do zooplâncton, destacando-se as clorófitas, com o gênero Scenedesmus, e as cianofíceas, com o gênero Microcystis, e entre o zooplâncton, a maior abundância foi de rotíferos dos gêneros Brachionus e Keratella, seguido por copépodas. O tratamento adubado com esterco de frangos possibilitou um maior desenvolvimento da comunidade planctônica, e melhores

  16. L'élevage larvaire des poissons marins : chaînes alimentaires et aliments composés

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    GIRIN M.

    1977-01-01

    Full Text Available L'approvisionnement quotidien en nourriture est, en règle générale, le principal facteur limitant de productions à grande échelle de jeunes poissons marins.La pêche de plancton dans la nature a été, et reste, le moyen d'expérimentation le plus immédiat, et le plus satisfaisant sur le plan qualitatif. Mais la récolte des quantités nécessaires, au moment voulu, devient très délicate dès que l'on dépasse l'échelle de l'aquarium. Le développement, ces dernières décennies, de techniques de production en masse d'animaux-proies a permis le lancement d'élevages à grande échelle. Parmi ces proies, le Branchiopode Artemia salina et le Rotifère Brachionus plicatilis dominent incontestablement ; tandis que l'élevage des Copépodes, part la plus intéressante du plancton naturel, reste encore mal maîtrisé. Cependant , l'élevage et l'emploi de proies vivantes, quelles qu'elles soient, imposent la réalisation d'installations coûteuses et l'emploi d'un abondant personnel qualifié. Il en est résulté récemment un important effort de recherche en direction de nourritures inertes, broyats , poudres et aliments composés, généralement abandonnés après les échecs enregistrés pendant les premières années du siècle. Quelques résultats encourageants ont été obtenus, mais ils restent limités et soulèvent de délicats problèmes d'hygiène des bacs d'élevage. L'emploi de proies vivantes , au moins pendant le premier mois des élevages , reste donc encore une obligation. Dans ce contexte, l'essentiel de l'effort actuel tend , d'une part à réduire leur durée d'emploi au minimum possible et, d'autre part, à rendre leur production plus rationnelle , en recherchant des méthodes qui évitent, pour leur alimentation , de faire appel à des algues planctoniques vivantes.

  17. Plankton and Macrobiota Composition and Diversity of Three Tropical Freshwaters Rivers in Ogun and Ondo States, Southwest Nigeria

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    Taofikat Abosede ADESALU

    2016-06-01

    Full Text Available Three different rivers in Ogun and Ondo states were investigated for both micro and macro-biota of the water bodies. Several physical and chemical properties of these rivers were determined. The pH value of the studied water bodies was essentially neutral with salinity values between 0.02 - 4.0‰. Microalgae communities were represented by three divisions: Cyanophyta, Bacillariophyta and Chlorophyta at Oluwa and Ifara Rivers (Ondo state, while at Ibefun River (Ogun state, five divisions: Cyanophyta, Bacillariophyta, Chlorophyta, Euglenophyta and Pyrrhophyta were identified. Diatoms dominated these water bodies, with Navicula radiosa Kutz. at Ifara River, Fragilaria sp. in Oluwa River, while out of 90 algal taxa identified in Ibefun river, 64 were diatoms species belonging to 26 genera, with Melosira sp. and Synedra sp. recording the highest numbers of cell count. Dinoflagellates recorded only Peridinium sp. while Phacus orbicularis Hubner and Trachelomonas sp. dominated the euglenoids. For the zooplankton composition at Ibefun, rotifers (75.95% were represented by Brachionus sp., which recorded 62.03%, and Gastropus sp. with 13.92% of the total zooplankton, thus dominated the spectrum, while the copepod recorded 22.78% of the total organisms, with Copilia sp. and Euchirella sp. having 8.86% each. The macrobenthic invertebrates were represented by 3 taxa, belonging to 3 groups, with the dominant group Insecta accounted for 57% of the total individuals (7 individuals/m2, while Oligochaeta and Hirudinea accounted for 29% and 14% respectively of the total individuals at Oluwa and Ifara Rivers. At Ibefun River, the macrobenthic invertebrates were represented by 5 taxa, belonging to 3 groups, Bivalves, Oligochaeta and Insecta, with bivalves being the dominant group (51.7% of the total individuals, as 64 individuals/m2, while Oligochaeta and Insecta accounted for 26.6% and 21.9% respectively of the total individuals. The dominant taxon, Macoma cumana

  18. Limnología e ictiofauna de la laguna José María (Córdoba, Argentina, con especial referencia al pejerrey (Odontesthes bonariensis -Valenciennes, 1835-

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    M. Mancini

    2016-09-01

    Full Text Available La región sur de la provincia de Córdoba presenta numerosas lagunas cuyo origen y salinidad varían ampliamente. Muchos de estos ambientes son utilizados para la pesca recreativa del pejerrey (Odontesthes bonariensis. El objetivo del presente trabajo fue caracterizar la calidad del agua y determinar la diversidad del zooplancton y de la ictiofauna con especial referencia a O. bonariensis, de la laguna José María (34º50’17’’S, 63º37’23’’O. Este ambiente se ubica en la cuenca del río Quinto (Córdoba y está comunicado con numerosas lagunas. Se analizaron in situ (n=8, el pH, el oxígeno, la temperatura y transparencia del agua y se tomaron muestras de agua y zooplancton para su análisis en laboratorio. Para la captura de peces se utilizaron redes de enmalle, arrastre, trampa y espineles. La profundidad promedio fue de 1,99 m, con un máximo de 2,20 m. Los registros medios del pH, oxígeno disuelto, temperatura y transparencia fueron 8,51, 9,03 mg/L, 24,3 ºC y 44 cm respectivamente. Por su transparencia, la laguna fue caracterizada como “turbia”. El agua se clasificó como oligohalina (4,09 g/L, sulfatada-sódica y muy dura (484 ppm de CO3Ca. El zooplancton estuvo representado por 3 especies de crustáceos y 7 de rotíferos. Entre los primeros, Metacyclops mendocinus fue el que registró la mayor densidad (162,2 ind/L, mientras que entre los rotíferos fue Brachionus plicatilis con 482,7 ind/L. Se capturaron 12 especies de peces, pertenecientes a 5 órdenes y 9 familias (Shannon = 2,23 bits. El pejerrey fue la especie de mayor abundancia (50,8% y junto al sabalito Cyphocharax voga y la carpa Cyprinus carpio representaron el 85 % del total de biomasa de los peces capturados. Los parámetros poblacionales de O. bonariensis fueron: Peso= 0,0000047081*LEst3,178 (R2=0,99, n=116; longitud total= 5,854+LEst*1,168 (R2= 0,99, n= 117; LEst(t= 489,02 (1-e-0,225(t-0,46 y W(t= 1647,5 (1- e-0,225(t-0,463,177.

  19. DESCRIPTION DE LA ZOOÉPIBIOSE DE L’ÉCREVISSE SIGNAL (PACIFASTACUS LENIUSCULUS, DANA EN ASTACICULTURE

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    CUELLAR M. C.

    2002-07-01

    Full Text Available Des recherches ont été effectuées concernant la zooépibiose de l’écrevisse signal (Pacifastacus leniusculus, D., provenant d’un centre d’astaciculture espagnol, au cours de la période 1997-1998. Les organismes épibiotiques dominants trouvés sur l’exosquelette appartiennent aux groupes zoologiques d’Invertébrés suivants : Mastigophora (Bodo, Cilliophora (Stentor, Epistylis, Zoothamnium, Acineta, Turbelaria (Temnocephala, Rotifera (Brachionus, Annelida (Branchiobdella, Acarina (Hygrobates et Ostracode (Eucypris ou Enthocytera, on souligne le nombre élevé de Branchiobdellides de l’espèce Branchiobdella instabilia M., dont les quantités minimum et maximum, en mâles et femelles, oscillent de 12 à 139 et de 7 à 130, respectivement. Les hyperbranchiobdelloses provoquent des automutilations, des décollements des pinces et autres appendices, des mues anormales, des lésions cuticulaires, de l’hémocytopénie et des changements éthologiques. Les colonisations maximales d’Ostracodes de l’espèce Eucypris virens, J.O., Enthocytera heterodonta, R., dans les poches d’incubation des femelles donnent lieu à une coloration rougeâtre des oeufs et à leur perte postérieure. Compte tenu de leur nombre limité et de la période d’épibiose, les genres des sous-types Mastigophora, Ciliophora, Turbelaria, Rotifera et Arachnida ne représentent aucun danger pour les écrevisses. En ce qui concerne la zooépibiose associée aux appendices et aux régions du corps des écrevisses du Pacifique, les chélipèdes ou pinces constituent le substrat où se place de préférence le genre Branchiobdella ; le céphalothorax sert de support à tous les groupes taxonomiques d’épibiontes identifiés.

  20. Caracterización limnológica de la laguna de Cashibococha (UcayaliPerú durante el año 2001

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    José Riofrío

    2013-06-01

    Full Text Available Durante el año 2001 se realizaron muestreos bimensuales en tres estaciones fijas en la laguna de Cashibococha (Ucayali, Perú. Cashibococha presenta aguas de color verdoso a café oscuro, con pH entre 6 a 6,8, Conductividad entre 10 y 30µS.cm −1 , Transparencia de 21 a 59 cm y Alcalinidad Total entre 14 y 22 mg CaCO3 / L . La temperatura superficial del agua osciló entre 24,4 y 37 ºC y el Oxígeno Disuelto entre 1,3 y 7,4 mg/ L. Los análisis bacteriológicos registraron recuentos de aerobios mesófilos entre 350 y 3600 UFC/ mL. Los coliformes totales oscilaron entre 3 y 43 NMP/ 100 mL. Se diferenciaron 47 especies pertenecientes a 20 familias de macrófitas acuáticas; el mayor número de especies se reportó durante la época de Transición − Creciente (octubre − noviembre, debido a la inundación del bosque. Fueron identificadas 52 especies de fitoplancton, la División Chlorophyta fue la mas dominante. La comunidad fitoplanctónica está dominada por las especies Actinastrum hantzschi, Spirogyra sp., Eudorina elegans, Pandorina morum y Closterium kuetzingui. Se diferenciaron 54 especies de Zooplancton. Los rotíferos fue el taxa dominante. La densidad de zooplancton está dominada por Brachionus patulus macracanthus y Polyarthra vulgaris. Fueron identificadas 66 especies de peces, pertenecientes a 55 géneros, 11 familias y 4 órdenes. El orden dominante en diversidad y abundancia fue el de Characiformes, Curimata vittata fue la especie dominante en la comunidad de peces en éstas áreas litorales. Los índices de diversidad fueron superiores a 3,0 bits. ind –1 , en todas las estaciones y lugares de muestreo. De igual manera los valores de equitabilidad fueron superiores a 0,8 en todas las estaciones y lugares de muestreo.

  1. Biotest- and chemistry-based hazard assessment of soils, sediments and solid wastes

    Energy Technology Data Exchange (ETDEWEB)

    Pollumaa, L.; Kahru, A. [National Inst. of Chemical Physics and Biophysics, Tallinn (Estonia); Manusadzianas, L. [Inst. of Botany, Vilnius (Lithuania)

    2004-07-01

    The aim of the current study was (1) to compare the ecotoxicity and chemistry-based environmental evaluations for 27 solid-phase environmental samples (soils, sediments, solid wastes); (2) to suggest the battery of biotests for the screening of water-extracted toxicity. 14 soils, 9 sediments and 4 oil-shale industry solid waste samples from Estonia and Lithuania were analyzed for the concentration of total PAHs, heavy metals, oil products and water-extracted phenols. The pollution level was evaluated by comparison of measured concentrations with Estonian permitted limit values in residential (PLV{sub r}) and industrial (PLV{sub i}) areas for each key pollutant. A battery of 8 aquatic toxicity tests was applied for the analysis of aqueous extracts (L/S=3) of samples: tests with microalgae Selenastrum capricornutum, macroalgae Nitellopsis obtusa, protozoa Tetrahymena thermophila, crustaceans Daphnia magna and Thamnocephalus platyurus, rotifers Brachionus calyciflorus and photobacteria Vibrio fischeri. Particle-bound bioavailable toxicity was evaluated using a kinetic photobacterial assay with Vibrio fischeri (Solid-Phase Flash-Assay). The toxicity data were evaluated by MaxTox index (highest toxic signal of the battery). Results. Chemical evaluation and toxicological evaluation pointed to the same direction in half of the cases (13/27): 5 samples (including 2 presumably clean control soils) proved harmless and 8 hazardous to environment in case of both evaluations. However, there was a disagreement between chemical and toxicological evaluations for the rest of the samples (14/27). In two mismatching cases (soils from the territory of former gasoline stations) the level of oil products exceeded the PLV{sub r}, but no toxicity was detected, most probably due to the low bioavailability of aged pollutants. The results of this study show the necessity of biotesting in environmental risk assessment to avoid the falsenegative results that may result in harmful effects for

  2. The use of multivariate analysis to link sediment contamination and toxicity data to establish sediment quality guidelines: an example in the Gulf of Cadiz (Spain); El uso del analisis multivariante en la union de datos de toxicidad y contaminacion para establecer guias de calidad de sedimento: Un ejemplo en la Bahia de Cadiz (Espana)

    Energy Technology Data Exchange (ETDEWEB)

    Del Valls, T. Angel; Forja, Jesus M [Departamento de Quimica Fisica, Facultad de Ciencias del Mar, Universidad de Cadiz, Cadiz, (Spain); Gomez-Parra, Abelardo [Instituto de Ciencias Marinas de Andalucia, CSIC, Puerto Real, Cadiz, (Spain)

    1998-03-01

    To evaluate marine sediment quality in the Gulf of Cadiz, chemical concentration and toxicity test endpoints from sediments were linked using multivariate analysis. Sediment samples were collected synoptically at seven stations in two littoral ecosystems of the Gulf of Cadiz (five in the Bay of Cadiz and two in the salt marsh of the Barbate River), and subjected to six separate, replicated sediment toxicity tests and comprehensive sediment chemistry analyses. The toxic effects of sediments were tested using three operational sediment phases: whole sediment, using the estuarine amphipod Microdeutopus gryllotalpa (10 d static: survival) and the estuarine clam Ruditapes philippinaru (48 h static: survival) and of the marine fish Sparus aurata (48 h static. Survival); and interstitial water, using populations of the estuarine rotifer Brachionus Plicatilis (7 d static: Population decline) and of the marine bacteria Photobacterium phosphoreum (Microtox ). To evaluate the levels of contamination, the concentrations in the sediments of organic carbon, 14 trace metals (Fe, Mn, Cu, Zn, Pb, Cd, Ag, Hg, As, Sn, V, Ni, Co and Cr) and the surfactant linear alkylbenzenesulphonate (LAS) were measured. The results of the toxicity tests were compared in a dose-response relationship between sites, demonstrating a general agreement between the toxicity values determined by all the tests, except in the case of interstitial water toxicity (principally due to toxic mixtures of trace metals). Data derived from sediment chemistry and bioassays were assembled by multivariate statistical techniques (PCA and factor analysis), showing that the two data types could be represented by only five factors corresponding to five overlapping chemical-biological effect relations. Positive prevalence of these factors in the cases studied was used to establish those ranges in chemical concentrations associated with adverse effects. The sediment quality guidelines, in terms of concentrations at or below

  3. Efeitos de fertilização na biomassa e qualidade nutricional do zooplâncton utilizado para alimentação de alevinos na estação de hidrobiologia e piscicultura de Furnas, MG Fertilization effects on biomass and nutritional quality of zooplancton in feeding of fry in the Furnas (MG, Brazil hydrobiology and pisciculture station

    Directory of Open Access Journals (Sweden)

    Raquel Magalhães Santeiro

    2000-05-01

    Full Text Available O estudo objetivou avaliar os efeitos da adição intensiva de dejetos orgânicos e de nutrientes na qualidade do zooplâncton obtido em tanques de plâncton, empregado na alimentação de alevinos de “trairão” (Hoplias lacerdae. Os teores de lipídeos totais do zooplâncton bem como sua abundância e biomassa foram acompanhados, através de duas coletas semanais, em dois tanques de produção de plâncton durante dois meses seguidos. Foram medidos ainda a temperatura, pH, oxigênio dissolvido, condutividade elétrica na coluna de água. As concentrações de clorofila-a, fósforo total, amônia e nitrogênio total (TKN foram acompanhadas semanalmente. Nos primeiros trinta dias, foi feita a adubação a cada cinco dias e, nos últimos trinta dias, não houve qualquer adubação em ambos os tanques. A interrupção da fertilização causou uma notável e rápida mudança na qualidade físico-química da água bem como na estrutura da comunidade zooplanctônica. Houve um decréscimo nos teores de condutividade, amônia, nitrogênio total, fósforo total e clorofila-a. Em contraste, houve um aumento nos níveis de oxigênio dissolvido e pH. Logo após a parada da fertilização, houve um pico na biomassa total do zooplâncton que perdurou por cerca de 20 dias, em ambos os tanques. Nesse período, o cladócero Moina reticulata e o rotífero Brachionus calyciflorus foram os mais abundantes. No entanto, ao final do período de estudos, os ciclopóides voltaram a ser os organismos dominantes, embora com predominância de formas imaturas. Os teores de lipídeos totais do zooplâncton permaneceram baixos durante todo o período de estudos (6-10%, sugerindo a má qualidade do seu alimento dentro dos tanques. O estudo demonstra que a fertilização é necessária para que seja obtido um zooplâncton com maiores valores nutricionais mas a baixa qualidade da água causada pela hipereutrofização e os baixos níveis de lipídeos encontrados no zoopl

  4. Repurposing FDA-approved drugs for anti-aging therapies.

    Science.gov (United States)

    Snell, Terry W; Johnston, Rachel K; Srinivasan, Bharath; Zhou, Hongyi; Gao, Mu; Skolnick, Jeffrey

    2016-11-01

    There is great interest in drugs that are capable of modulating multiple aging pathways, thereby delaying the onset and progression of aging. Effective strategies for drug development include the repurposing of existing drugs already approved by the FDA for human therapy. FDA approved drugs have known mechanisms of action and have been thoroughly screened for safety. Although there has been extensive scientific activity in repurposing drugs for disease therapy, there has been little testing of these drugs for their effects on aging. The pool of FDA approved drugs therefore represents a large reservoir of drug candidates with substantial potential for anti-aging therapy. In this paper we employ FINDSITE(comb), a powerful ligand homology modeling program, to identify binding partners for proteins produced by temperature sensing genes that have been implicated in aging. This list of drugs with potential to modulate aging rates was then tested experimentally for lifespan and healthspan extension using a small invertebrate model. Three protein targets of the rotifer Brachionus manjavacas corresponding to products of the transient receptor potential gene 7, ribosomal protein S6 polypeptide 2 gene, or forkhead box C gene, were screened against a compound library consisting of DrugBank drugs including 1347 FDA approved, non-nutraceutical molecules. Twenty nine drugs ranked in the top 1 % for binding to each target were subsequently included in our experimental analysis. Continuous exposure of rotifers to 1 µM naproxen significantly extended rotifer mean lifespan by 14 %. We used three endpoints to estimate rotifer health: swimming speed (mobility proxy), reproduction (overall vitality), and mitochondria activity (cellular senescence proxy). The natural decline in swimming speed with aging was more gradual when rotifers were exposed to three drugs, so that on day 6, mean swimming speed of females was 1.19 mm/s for naproxen (P = 0.038), 1.20 for fludarabine (P = 0

  5. Characterization of biocenosis in the storage-reservoirs of liquid radioactive wastes of 'Mayak' PA

    Energy Technology Data Exchange (ETDEWEB)

    Pryakhin, E.; Tryapitsina, G.; Andreyev, S.; Akleyev, A. [Urals Research Center for Radiation Medicine - URCRM (Russian Federation); Mokrov, Y.; Ivanov, I. [Mayak PA (Russian Federation)

    2014-07-01

    cycle. In reservoir R-3 there was no small pelophylic mollusks either, 90% of zooplankton community was represented by rotifers, in zoo-benthos community there was no small pelophylic mollusks, in species composition of ichthyofauna there was no carnivorous species of fish. In reservoir R-17 ichthyofauna was completely absent, species diversity of phytoplankton was significantly reduced, zooplankton was represented only by rotifers, and zoo-benthos was represented only by gnat larvae. In reservoir R-9 there was no ichthyofauna; phytoplankton was almost a mono-culture of cyanobacteria Geitlerinema amphibium, zooplankton was almost a mono-culture of rotifers Brachionus calyciflorus or Hexartra fennic in different years. In all of the above mentioned reservoirs, the development of bacterial plankton was at the levels characteristic of the standing water bodies of this geographical zone. Document available in abstract form only. (authors)

  6. Review on the acute Daphnia magna toxicity test – Evaluation of the sensitivity and the precision of assays performed with organisms from laboratory cultures or hatched from dormant eggs

    Directory of Open Access Journals (Sweden)

    Persoone G.

    2009-08-01

    daphnids from lab cultures. The obvious advantages of Daphnia microbiotests over tests with Daphnias stemming from lab cultures have led to the worldwide use of these culture/maintenance free and low cost small-scale assays in both research and toxicity monitoring. The Daphnia microbiotest is in current use in several countries for toxicity testing in a regulatory framework, and recent calculations indicate that about 10 000 acute D. magna assays are now performed annually with neonates hatched from dormant eggs. The use of dormant eggs to obtain test organisms independently of stock culturing has recently also been accepted in international standards for toxicity testing. ISO standard 20665 (2008 related to the determination of chronic toxicity with Ceriodaphnia dubia, and ISO standard 20666 (2008 for the determination of the chronic toxicity with Brachionus calyciflorus in 48 h, both indicate that the assays can be conducted with organisms hatched from dormant eggs. On the basis of the extensive scientific evidence provided in this review that is justifiably supported by the two ISO methods mentioned above, the authors therefore recommend that the use of Daphnias hatched from dormant eggs should also be incorporated in national and international standards, as an alternative to the use of Daphnias taken from laboratory cultures.

  7. Zoo-heleoplankton structure in three artificial ponds of North-eastern Argentina

    Directory of Open Access Journals (Sweden)

    S. M Frutos

    2008-09-01

    Full Text Available The aim of the present study was to compare the abundance and species richness of zoo-heleoplankton bigger than 53 µm in an annual cycle under similar climate conditions in three artificial ponds, in order to observe the changes during an annual cycle. Samples were taken monthly from June 1993 to July 1994 in Corrientes, Argentina. The first pond (A was covered an 80% by Eichhornia crassipes (Mart., the second one (B with bloom of Microcystis aeruginosa (Kurtzing and the last one (C with organic matter deposited in the bottom. The water was more acidic at pond A, and the water at pond B contained more dissolved oxygen concentration than the water at the other two ponds. The zoo-heleoplankton densities varied between 20-1728 ind.l-1 at pond A, 42-4082 ind.l-1 at pond B and 148-2447 ind.l-1 at pond C. The maximum zoo-heleoplankton abundance was found in the pond with cyanobacteria bloom during Autumn 1994 and the minimum abundance was found in the one with a predominance of E. crassipes. The rank of species richness was pond A > pond B > pond C. Rotifera was the most abundant group in pond A whereas the larval stages of Copepoda were abundant in the other two ponds. Anuraeopsis navicula Rousselt 1910 was the dominant population in the pond with macrophytes prevalence. Brachionus calyciflorus Pallas 1776 and larval stage of Copepoda had variable proportions in the pond with cyanobacteria bloom. Thermocyclops decipiens (Kiefer 1929 was present during the annual cycle only in the pond with organic matter deposited in the bottom. The succession of taxa was observed in the pond with coverage of aquatic macrophytes and with cyanobacteria bloom. Differences in species richness and low similarity in zoo-heleoplankton between ponds were determined by differences in the quality of the water in relation to the presence of macrophytes, cyanobacteria, organic matter deposited in the bottom and fish predation. Multiple regression analysis (stepwise revealed

  8. Review on the acute Daphnia magna toxicity test – Evaluation of the sensitivity and the precision of assays performed with organisms from laboratory cultures or hatched from dormant eggs

    Directory of Open Access Journals (Sweden)

    G. Persoone

    2009-08-01

    dormant eggs.The use of dormant eggs to obtain test organisms independently of stock culturing has recently also been accepted in international standards for toxicity testing. ISO standard 20665 (2008 related to the determination of chronic toxicity with Ceriodaphnia dubia, and ISO standard 20666 (2008 for the determination of the chronic toxicity with Brachionus calyciflorus in 48 h, both indicate that the assays can be conducted with organisms hatched from dormant eggs.On the basis of the extensive scientific evidence provided in this review that is justifiably supported by the two ISO methods mentioned above, the authors therefore recommend that the use of Daphnias hatched from dormant eggs should also be incorporated in national and international standards, as an alternative to the use of Daphnias taken from laboratory cultures.