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

Revisão de Alchisme Kirkaldy (Hemiptera, Membracidae, Membracinae, Hoplophorionini Revision of Alchisme Kirkaldy (Hemiptera, Membracidae, Membracinae, Hoplophorionini

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Antonio J. Creão-Duarte

1997-01-01

Full Text Available Thirty four (34 species of Alchisme Kirkaldy, 1904 are presented with descriptions, illustrations, and key for identification, except for two of them which were not seen, A. truncaticornis (Germar, 1835 and A. intermedia (Distant, 1881. The following nomenclatural changes are introduced: Achisme intermedia (Distant, 1881, sp. rev.; A. testacea (Fairmaire, 1846, sp. rev.; Alchisme apicalis (Walker, 1851 = A. costaricensis Goding, 1929, syn.n.; A. inermis (Fairmaire, 1846 = Triquetra nigrocarinala Fairmaire, 1846, syn.n.; A. rubrocostata (Spinola, 1852 = A. neuquina Remes-Lenicov, 1978, syn.n.; A. turrita (Germar, 1835 = Triquetra submaculata Buckton, 1901, syn.n.; A. ustulata (Fairmaire, 1846 = Triquetra virgata Fairmaire, 1846, syn.n.; A. virescens (Fairmaire, 1846 = Alchisme spinosa Funkhouser, 1940, syn.n.; Alchisme banosiensis sp.n. (from Ecuador; A. bordoni sp.n. (from Venezuela; A. colombiana sp.n. (from Colombia; A. salta sp.n. (from Argentina; A. cultellata sp.n. (from Venezuela; A. deflexa sp.n. (from Venezuela; A. erecta sp.n. (from Venezuela; A. frontomaculata sp.n. (from Brazil; A. goiana sp.n. (from Brazil; A. henryi sp.n. (from Venezuela; A. insolita sp.n. (from Colombia; A. mackameyi sp.n. (from Ecuador; A. onorei sp.n. (from Ecuador; A. schuhi sp.n. (from Peru.

Fungal species associated with Vigna unguiculata (L.) Walp (Cowpea)

African Journals Online (AJOL)

Aspergillus niger Van Tieghem, Botryodiplodia theobromae (Pat) Novel, Fusarium oxysporum Schlecht and Rhizopus stolonifer Ehrenb ex Link were isolated from both blotter and agar methods. Botryodiplodia theobromae had the highest mean occurrence (42.37%) followed by Fusarium oxysporum (30.02%), Aspergillus ...

Hongos tremeloides (Heterobasidiomycetes de la Reserva de la Biosfera de Calakmul, Campeche, México Tremelloid fungi (Heterobasidiomycetes from Calakmul Biosphere Reserve, Campeche, Mexico

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Sigfrido Sierra

2012-03-01

Full Text Available Se registran 7 especies de hongos tremeloides de la Reserva de la Biosfera de Calakmul: Auricularia cornea Ehrenb., A. delicata (Fr. Henn., A. mesenterica (Dicks. Pers., Dacryopinax elegans (Berk. et M.A. Curtis G.W. Martin, D. spathularia (Schwein. G.W. Martin, Tremella wrightii Berk. et M.A. Curtis y Tremelloscypha gelatinosa (Murrill Oberw. et K. Wells. Todas son registros nuevos para la reserva. Auricularia cornea y T. gelatinosa son nuevos registros para el estado de Campeche.Seven species of tremelloid fungi are recorded from Calakmul Biosphere Reserve: Auricularia cornea Ehrenb., A. delicata (Fr. Henn., A. mesenterica (Dicks. Pers., Dacryopinax elegans (Berk. et M.A. Curtis G.W. Martin, D. spathularia (Schwein. G.W. Martin, Tremella wrightii Berk. et M.A. Curtis and Tremelloscypha gelatinosa (Murrill Oberw. et K. Wells. All are new records for the reserve. Auricularia cornea and T. gelatinosa are new records for Campeche state.

Inhibition of the development of pathogenic fungi by extracts of some ...

African Journals Online (AJOL)

The different marine algae belonged to Chlorophyta (Enteromorpha prolifera and Ulva reticulata), Phaeophyta (Cystoseira myrica, Padina pavonica, Sargassum portieriatum and Turbinaria triquetra) and Rhodophyta (Gracilaria multipartita). Algal extraction was achieved successively by using petroleum ether, diethyl ether, ...

Colacium Minimum (Euglenophyta, A New Epiphytic Species For Asia

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Wołowski Konrad

2015-12-01

Full Text Available Colacium minimum Fott & Komárek, known so far from a few localities in Central Europe (Czech Republic, is reported here for the first time from Asia (Thailand. This epiphytic species was found growing on eight taxa of loricated euglenoids. The process of surface colonization of Trachelomonas Ehrenb. and Strombomonas Deflandre taxa by C. minimum in natural populations is briefly discussed and originally documented using LM and SEM.

Typification of the Linnaean names Plantago serraria and P. subulata (Plantago subgenus i>Coronopus>, Plantaginaceae)

DEFF Research Database (Denmark)

Hassemer, Gustavo; Iamonico, Duilio; Rønsted, Nina

2017-01-01

Plantago subg. Coronopus is a mainly Mediterranean group of plantains whose taxonomy is very complex. Two Linnaean names within this subgenus still remain untypified: P. serraria and P. subulata. We here discuss the possible types for these names, and designate lectotypes for both. For nomenclatu....... For nomenclatural purposes, the names P. triquetra and P. pungens are also included in the treatment of P. subulata....

Annotated Directory of Threatened and Endangered Wildlife on Selected U.S. Army Installations East of the Mississippi River

Science.gov (United States)

1991-05-01

species was historically collected from the Illinois River, in waters around the installation. Higgins eye, Lampsilis higginsi (SE): Historically...triquetra (SE): Found in the Mississippi River, this species may occur in waters around the installation. Higgins eye, Lampsilis higginsi (FE, SE): Found in...tributaries of the Tennessee river, it may still be present in waters around the installation. 131 Cumberland monkeyface, Quadrula intermedia (FE, SE

Lipid biomarkers : Linking the utilization of frontal plankton biomass to enhanced condition of juvenile North Sea cod

DEFF Research Database (Denmark)

St. John, Michael; Lund, T.

1996-01-01

, hatched and the N1 nauplii from these different feeding regimes fed to post yolk-sac larval North Sea cod. Post yolk-sac larval cod required 8 d on either a Heterocapsa- or Skeletonema-based food chain before tracer Lipid signals (the ratio of the lipids 16:1 omega 7 to 16:0) in the larvae began to change...

Tamarix duezenlii (Tamaricaceae - a species new to science from southern Turkey

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Halil Çakan

2011-01-01

Full Text Available Tamarix duezenlii, belonging to Tamarix L. ser. Leptostachyae (Bunge Baum, is described as a species new to science. It is related to T. hispida Willd. and T. arborea (Sieber ex Ehrenb. Bunge. From the former species it differs by its dense inflorescences, white petals and paralophic disc; from the latter by a shrubby habit, elliptic petals and calyx abruptly narrowed at the base. The species occurs in saline areas of the Cukurova Deltas at the mouths of the Seyhan and Ceyhan rivers in southern Turkey.

Feeding behaviour of the nauplii of the marine calanoid copepod Paracartia grani Sars: Functional response, prey size spectrum, and effects of the presence of alternative prey.

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Laura K Helenius

Full Text Available Laboratory feeding experiments were conducted to study the functional response and prey size spectrum of the young naupliar stages of the calanoid copepod Paracartia grani Sars. Experiments were conducted on a range of microalgal prey of varying sizes and motility patterns. Significant feeding was found in all prey of a size range of 4.5-19.8 μm, with Holling type III functional responses observed for most prey types. The highest clearance rates occurred when nauplii fed on the dinoflagellate Heterocapsa sp. and the diatom Thalassiosira weissflogii (respectively, 0.61 and 0.70 mL ind-1 d-1, suggesting an optimal prey:predator ratio of 0.09. Additional experiments were conducted to examine the effects of the presence of alternative prey (either Heterocapsa sp. or Gymnodinium litoralis on the functional response to the haptophyte Isochrysis galbana. In the bialgal mixtures, clearance and ingestion rates of I. galbana along the range of the functional response were significantly reduced as a result of selectivity towards the larger, alternative prey. Paradoxically, relatively large prey trigger a perception response in the nauplii, but most likely such prey cannot be completely ingested and a certain degree of sloppy feeding may occur. Our results are further evidence of the complex prey-specific feeding interactions that are likely to occur in natural assemblages with several available prey types.

Flora planctónica de laguna Lagartos, Quintana Roo Planktonic flora from Lagartos Lagoon, Quintana Roo

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Viridiana Margarita Nava-Ruiz

2012-09-01

Full Text Available Se presenta una lista de la flora planctónica de la laguna Lagartos, basada en la observación de muestras superficiales obtenidas entre noviembre de 2007 a septiembre de 2008. Las muestras se recolectaron con una botella Van Dorn de 2 litros en la parte central de la laguna; se registraron 67 taxa: 28 Bacillariophyta, 22 Cyanoprokaryota, 7 Chlorophyta, 6 Dinoflagellata, 2 Euglenophyta y 2 Cryptophyta. Las cianofitas dominaron durante todo el periodo de estudio, con una contribución mayor al 80% de la abundancia total del fitoplancton. Son nuevos registros para México 13 especies: Chroococcus pulcherrimus, Coelosphaerium confertum, Cyanodyction iac, Phormidium pachydermaticum, Planktolyngbya contorta, Rhodomonas minuta, Amphidinium massartii, Ensiculifera cf. loeblichii, Heterocapsa cf. pseudotriquetra, Prorocentrum cassubicum, Licmophora normaniana, Fistulifera saprophila y Amphora richardiana. Todos los taxa listados se ilustran con microfotografías.The planktonic flora from Lagartos Lagoon, Quintana Roo, was examined based on the observation of samples collected from November 2007 to September 2008. The superficial samples were collected with a Van Dorn bottle of 2 L, in the core part of the lagoon. A total of 67 taxa were identified: 28 Bacillariophyta, 22 Cyanoprokaryota, 7 Chlorophyta, 6 Dinoflagellata, 2 Euglenophyta and 2 Cryptophyta. Nevertheless, the blue green algae dominated during all study period, with more of 80% to the total abundance of the phytoplankton. The species Chroococcus pulcherrimus, Coelosphaerium confertum, Cyanodyction iac, Phormidium pachydermaticum, Planktolyngbya contorta, Rhodomonas minuta, Amphidinium massartii, Ensiculifera cf. loeblichii, Heterocapsa cf. pseudotriquetra, Prorocentrum cassubicum, Licmophora normaniana, Fistulifera saprophila and Amphora richardiana were recorded for the first time in Mexico. All the taxa are illustrated with microphotographs.

Diatom production in the marine environment : implications for larval fish growth and condition

DEFF Research Database (Denmark)

St. John, Michael; Clemmesen, C.; Lund, T.

2001-01-01

To test the effects of diatom production on larval fish growth and condition. laboratory experiments were performed with larval North Sea cod reared on different algal food chains. These food chains were based on cultures of (a) the diatoms Skeletonema costatum and Thalassiosira weissflogii: (b....../omega6 fatty acids in the algal source had no significant effect. The highest and lowest growth rates were observed in food chains based on H. triquetra and T. weissflogii. respectively (means for days 14-16 of 4.0 and - 4.7). The mixed diatom/dinoflagellate diet resulted in inter- mediate growth rates...... and condition. Regressions of growth rates against EPA and DHA content indicated no inhibitory effect of diatom production on growth in larval cod...

Development of high efficiency micropropagation protocol for tamarix nilotica ehrenb with valued medicinal properties

International Nuclear Information System (INIS)

Qurainy, F. A.; Nadeem, M.; Khan, S.; Tarroum, M.; Alansi, S.

2015-01-01

Tamarix nilotica is an important medicinal plant grows throughout the Kingdom, except in mountains on high altitude. Propagation of T. nilotica through cuttings and seeds are limited. To supplement harvesting of active ingredient from plants, alternative method for the purpose has been developed. Stem node cuttings were subjected to in vitro culture under the influence of various cytokinin to induce shoot proliferation. Maximum shoot stimulation was found on MS medium comprising 1.0 micro M TDZ followed by 2.5 micro M BA, Kn and 2ip. The number of shoots declined as the concentration of cytokinin increased. A lower shoots obtained on 5.0 and 10.0 micro M concentration of all the four cytokinins tested. After fair multiplication, individual shoots were subjected to different concentration of auxins IBA, NAA, 2,4-D and AA 2.5-10.0 micro M for root induction. Initial screening did not result desired rooting on MS medium. Therefore, pulse treatment of 100 micro M IBA was given to the isolated shoots for 5, 10 and 15 days time. Incubation for 10 days on MS medium supplied with 100.0 micro M resulted in maximum rooting when transferred on MS medium alone. Well rooted microshoots were exposed to four types of soil mixtures for acclimatization of plants. Among these soils, sand and FYM gave 100 percentage survival under controlled green house conditions. This protocol would be helpful in regeneration and conservation of this plant species; and provide an alternative source of biomass for pharmaceutical active ingredients. (author)

Novas ocorrências de desmídias filamentosas (Desmidiaceae, Zygnematophyceae para o estado da Bahia, Brasil New records of filamentous desmids (Desmidiaceae, Zygnematophyceae from Bahia state, Brazil

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Ivania Batista de Oliveira

2010-12-01

Full Text Available As desmídias de hábito filamentos são constituídas por filamentos de células relativamente curtos, que se dissociam com certa facilidade. O conhecimento destas algas no estado da Bahia é bastante escasso, até o momento, estando restrito a 13 táxons. O presente trabalho teve por objetivo realizar o inventário taxonômico dos gêneros filamentosos da família Desmidiaceae (Zygnematophyceae, de duas áreas de proteção ambiental, APA Rio Capivara e APA Lagoas de Guarajuba, município de Camaçari, a fim de ampliar o conhecimento destes na Bahia. Foram analisadas 33 amostras coletadas de acordo com os métodos usuais empregados nos estudos de taxonomia de microalgas continentais. Foram identificados 15 táxons distribuídos em sete gêneros (Bambusina Kütz. ex Kütz, Desmidium C.Agardh ex Ralfs, Groenbladia Teiling, Hyalotheca Ehrenb. ex Ralfs, Onychonema Wallich, Spondylosium Bréb. ex Kütz. e Teilingia Bourr., dos quais nove táxons constituem-se adições à flora de algas continentais da Bahia, aumentando o total de espécies conhecidas para 22.The filamentous desmids are composed of relatively short filaments of cells that dissociate rather easily. These algae are poorly known today in the state of Bahia, being restricted to 13 taxa. This study aimed to do a taxonomic inventory of filamentous genera of the family Desmidiaceae (Zygnematophyceae from two environmental protection areas, Rio Capivara and Lagoas de Guarajuba, Camaçari municipality, to increase our knowledge of these organisms in Bahia. We analyzed 33 samples collected according to the methods employed in studies of continental microalgae taxonomy. 15 taxa were recorded, distributed in seven genera: Bambusina Kütz. ex Kütz, Desmidium C.Agardh ex Ralfs, Groenbladia Teiling, Hyalotheca Ehrenb. ex Ralfs, Onychonema Wallich, Spondylosium Bréb. ex Kütz. and Teilingia Bourr. Of these, nine are additions to the algal flora of continental Bahia, increasing the total to 22

Tamarix arborea var. arborea and Tamarix parviflora: Two species valued for their adaptability to stress conditions.

Science.gov (United States)

Grisafi, Francesca; Oddo, Elisabetta; Gargano, Maria Letizia; Inzerillo, Simone; Russo, Gianni; Venturella, Giuseppe

2016-03-01

The choice of stress resistant and highly adaptable species is a fundamental step for landscaping and ornamental purposes in arid and coastal environments such as those in the Mediterranean basin. The genus Tamarix L. includes about 90 species with a high endurance of adversity. We investigated the water relations and photosynthetic response of Tamarix arborea (Sieb. ex Ehrenb.) Bge. var. arborea and T. parviflora DC. growing in an urban environment. Both species showed no evidence of drought or salt stress in summer, and appeared to follow two strategies with T. arborea var. arborea investing in high carbon gain at the beginning of the summer, and then reducing photosynthetic activity at the end of the season, and T. parviflora showing lower but constant levels of photosynthetic activity throughout the vegetative season. For landscaping and ornamental purposes, we suggest T. arborea var. arborea when a fast-growing, high-cover species is necessary, and T. parviflora when less-invasive species are required.

A check-list of the pentastomid parasites of crocodilians and freshwater chelonians

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K. Junker

2006-09-01

Full Text Available Based on published records and own data a summary is given of the geographical distribution of the currently known species of pentastomid parasites infecting crocodiles and alligators, as well as freshwater chelonians. A brief generic diagnosis is provided for each genus. Fourteen out of the currently 23 living crocodilian species have been recorded as being host to one or more pentastomes. Out of the 32 pentastome species six are considered species inquirendae. Presently, six genera of crocodilian pentastomes, Agema, Alofia, Leiperia, Sebekia, Selfia and Subtriquetra are recognized. African crocodiles harbour eight pentastome species, six of which have been recorded from the Nile crocodile, Crocodylus niloticus. Three species belong to the genus Sebekia, Alofia being represented by two and Leiperia by only one species. Two species, Alofia parva and Agema silvaepalustris, occur in the dwarf crocodile, Osteolaemus tetraspis, and the slender-snouted crocodile, Crocodylus cataphractus, exclusively, but a single Sebekia species is shared with the Nile crocodile. The genus Agema is endemic to the African region. Infective stages of the pentastome Sub triquetra rileyi, thought to utilize Nile crocodiles as final hosts, have been recovered only from fishes. The largest number of pentastome species is found in the Australasian region. Of these, the Indo-Pacific croc odile, Crocodylus porosus, harbours seven, representing the genera Alofia, Sebekia, Lei peria and Selfia. Selfia is exclusive to the latter host. The genus Subtriquetra has been reported from "Indian crocodiles", a term possibly referring to either Crocodylus palustris, Crocodylus porosus or Gavialis gangeticus. Ten species of pentastomes parasitizing the crocodilian genera Alligator, Caiman, Crocodylus and Melanosuchus have been recorded from the Neotropical region including the southern states of the North American continent. The two most wide-spread pentastome genera, Alofia and Sebekia

Survey on germination and species composition of dinoflagellates from ballast tanks and recent sediments in ports on the South Coast of Finland, North-Eastern Baltic Sea

International Nuclear Information System (INIS)

Pertola, Sari . E-mail sari.pertola@fimr.fi; Faust, Maria A.; Kuosa, Harri

2006-01-01

Cyst beds in ships and ports in Finland have previously been unstudied. Therefore, sediments from ships' ballast water tanks and four Finnish ports were sampled for dinoflagellate cysts and other phytoplankton. Untreated sediments were incubated at 10 o C and 20 o C in the local 6 psu salinity for 1, 4 and 7 days, and vegetative cells were examined with light and scanning electron microscope. Sediments were inhabited by various dinoflagellates, diatoms, chlorophytes, cyanophytes and small flagellates. Germinated dinoflagellates were found in 90% of ballast tanks and in all ports. Gymnodiniales spp. and Heterocapsa rotundata formed a major proportion of the proliferating dinoflagellate cells. One species, Peridinium quinquecorne, not previously reported from the Baltic Sea, was identified with SEM. The study emphasises that ships are potential transport vehicles for dinoflagellate cysts even in the low salinity Finnish waters, and small-sized dinoflagellates should be focused upon in ballast water studies

Caracterización cultural y morfológica e identificación de 12 aislamientos fungosos de semillas de Leucaena leucocephala cv. Perú Cultural and morphological characterization and identification of 12 fungal isolations in seeds of Leucaena leucocephala cv. Peru

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J. C Lezcano

2010-03-01

Full Text Available La presente investigación tuvo como objetivo identificar los agentes fungosos asociados a las semillas de Leucaena leucocephala cv. Perú almacenadas al ambiente, a partir de la caracterización cultural y morfológica de 12 aislamientos puros; estos se obtuvieron de la siembra de las estructuras fúngicas (vegetativas y/o reproductivas, en placas Petri (9 cm de diámetro que contenían Agar Papa Dextrosa (APD y Agar Malta (AM. Las placas se incubaron durante 10 días a 25ºC, con alternancia de 8 h luz/16 h oscuridad o a oscuridad constante, según los requerimientos de cada organismo. Se identificaron siete agentes fungosos asociados a las semillas, los cuales se clasificaron teniendo en cuenta los caracteres culturales y morfológicos, y se corroboraron con las claves taxonómicas. Ello permitió agrupar: Penicillium expansum Link, Rhizopus stolonifer Ehrenb. ex Fr., Cladosporium sphaerospermum Penz., Chaetomium indicum Corda, Alternaria alternata (Fr Keissl., Pestalotia sp. y Trichoderma sp. Dichos caracteres constituyen una herramienta importante para la identificación de los hongos hasta el nivel de especie, por lo que se recomienda realizar nuevos estudios con los aislamientos #9 y #11 con vista a completar la identificación hasta la especie en el caso de los géneros Trichoderma y Pestalotia; así como identificar las especies fungosas del resto de los aislamientos.The objective of this study was to identify the fungal agents associated to seeds of Leucaena leucocephala cv. Peru stored under ambient conditions, from the cultural and morphological characterization of 12 pure isolations; they were obtained from planting the fungal structures (vegetative and/or reproductive, in Petri dishes (9 cm diameter which contained Potato Dextrose Agar (PDA and Malt Agar (MA. The dishes were incubated for 10 days at 25ºC, alternating 8 h light/16 h darkness or at constant darkness, according to the requirements of each organism. Seven fungal

Spatial and temporal variations of Cocconeis placentula var. euglypta (Ehrenb. 1854 Grunow, 1884 in drift and periphyton

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EN. Gari

Full Text Available Spatial and temporal variations of Cocconeis placentula var. euglypta in drift and periphyton were studied in mountain streams of the Córdoba Province (Argentina. The sampling program was conducted in study sites located on a confluence between different order streams during an annual cycle. Samples were also taken every two hours during the daylight period in high and low water conditions. The relationship between drift and cellular reproduction was evaluated by valve length biometrics analysis. C. placentula var. euglypta drift was continuous; its density was not always dependent on periphyton density in each locality. C. placentula var. euglypta drift could be related to abiotic factors such as temperature and flow during the annual cycle. There were significant differences between periphyton and drift valve lengths. Moreover, drift can be associated with cellular reproduction because density was higher when valve lengths were shorter at different hours of the day. C. placentula var. euglypta epiphytims on Cladophora glomerata also influenced drift density and size distribution, modifying the relationship between periphyton and drift during the late spring when C. placentula var. euglypta was detached from senescent mats.

Survey on germination and species composition of dinoflagellates from ballast tanks and recent sediments in ports on the South Coast of Finland, North-Eastern Baltic Sea

Energy Technology Data Exchange (ETDEWEB)

Pertola, Sari [Finnish Institute of Marine Research, Department of Biological Research, P.O. Box 2, FI-00561 Helsinki (Finland)]. E-mail sari.pertola@fimr.fi; Faust, Maria A. [Department of Botany, US National Herbarium, Smithsonian Institution, 4210 Silver Hill Road, Suitland, Maryland 20746 (United States); Kuosa, Harri [Tvaerminne Zoological Station, University of Helsinki, FI-10900 Hanko (Finland)

2006-08-15

Cyst beds in ships and ports in Finland have previously been unstudied. Therefore, sediments from ships' ballast water tanks and four Finnish ports were sampled for dinoflagellate cysts and other phytoplankton. Untreated sediments were incubated at 10 {sup o}C and 20 {sup o}C in the local 6 psu salinity for 1, 4 and 7 days, and vegetative cells were examined with light and scanning electron microscope. Sediments were inhabited by various dinoflagellates, diatoms, chlorophytes, cyanophytes and small flagellates. Germinated dinoflagellates were found in 90% of ballast tanks and in all ports. Gymnodiniales spp. and Heterocapsa rotundata formed a major proportion of the proliferating dinoflagellate cells. One species, Peridinium quinquecorne, not previously reported from the Baltic Sea, was identified with SEM. The study emphasises that ships are potential transport vehicles for dinoflagellate cysts even in the low salinity Finnish waters, and small-sized dinoflagellates should be focused upon in ballast water studies.

Assessing the viability of microorganisms in the ballast water of vessels transiting the North Atlantic Ocean.

Science.gov (United States)

Steichen, Jamie L; Quigg, Antonietta

2015-12-15

Testing phytoplankton viability within ballast tanks and receiving waters of ballast water discharge remain understudied. Potentially harmful dinoflagellates and diatoms are transported via ballast water to Galveston Bay, Texas (USA), home to three major ports: Houston, Texas City and Galveston. Ballast water from vessels transiting the North Atlantic Ocean was inoculated into treatments representing low and high salinity conditions similar to the Ports of Houston and Galveston respectively. Phytoplankton in ballast water growout experiments were deemed viable and showed growth in low and mid salinities with nutrient enrichment. Molecular methods identified several genera: Dinophysis, Gymnodinium, Gyrodinium, Heterocapsa, Peridinium, Scrippsiella, Chaetoceros and Nitzschia. These phytoplankton genera were previously identified in Galveston Bay except Scrippsiella. Phytoplankton, including those capable of forming harmful algal blooms leading to fish and shellfish kills, are transported to Galveston Bay via ballast water, and are viable when introduced to similar salinity conditions found in Galveston Bay ports. Copyright © 2015 Elsevier Ltd. All rights reserved.

Hepatoprotective and antioxidant activities of Tamarix nilotica flowers.

Science.gov (United States)

Abouzid, Sameh; Sleem, Amany

2011-04-01

 Tamarix nilotica (Ehrenb.) Bunge (Tamaricaceae) is used in the Egyptian traditional medicine as an antiseptic agent. This plant has been known since pharaonic times and has been mentioned in medical papyri to expel fever, relieve headache, to draw out inflammation, and as an aphrodisiac. No scientific study is available about the biological effect of this plant.  This study aimed to evaluate the hydro-alcoholic extract (80%) of T. nilotica flowers for hepatoprotective and antioxidant activities.  Hepatoprotective activity was assessed using carbon tetrachloride-induced hepatic injury in rats by monitoring biochemical parameters. Antioxidant activity was evaluated in alloxan-induced diabetic rats. Biochemical markers of hepatic damage such as serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), alkaline phosphatase (ALP), and tissue glutathione were determined in all groups.  Carbon tetrachloride (5 mL/kg body weight) enhanced the SGOT, SGPT, and ALP levels. There was a marked reduction in tissue glutathione level in diabetic rats. The hydro-alcoholic extract of T. nilotica (100 mg/kg body weight) ameliorated the adverse effects of carbon tetrachloride and returned the altered levels of biochemical markers near to the normal levels.

Photosynthetic carbon metabolism in seagrasses C-labeling evidence for the c(3) pathway.

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Andrews, T J; Abel, K M

1979-04-01

The delta(13)C values of several seagrasses were considerably less negative than those of terrestrial C(3) plants and tended toward those of terrestrial C(4) plants. However, for Thalassia hemprichii (Ehrenb.) Aschers and Halophila spinulosa (R. Br.) Aschers, phosphoglycerate and other C(3) cycle intermediates predominated among the early labeled products of photosynthesis in (14)C-labeled seawater (more than 90% at the earliest times) and the labeling pattern at longer times was brought about by the operation of the C(3) pathway. Malate and aspartate together accounted for only a minor fraction of the total fixed label at all times and the kinetic data of this labeling were not at all consistent with these compounds being early intermediates in seagrass photosynthesis. Pulse-chase (14)C-labeling studies further substantiated these conclusions. Significant labeling of photorespiratory intermediates was observed in all experiments. The kinetics of total fixation of label during some steady-state and pulse-chase experiments suggested that there may be an intermediate pool of inorganic carbon of variable size closely associated with the leaves, either externally or internally. Such a pool may be one cause for the C(4)-like carbon isotope ratios of seagrasses.

Bioaccumulation of technetium by marine phytoplankton

International Nuclear Information System (INIS)

Fisher, N.S.

1982-01-01

/sup 95m/Tc, in the IV and VII oxidation states, was added in picomolar quantities to monocultures of seven species of marine phytoplankton, including a green algae (Dunaliella tertiolecta), a diatom (Thalassiosira pseudonana), a blue-green alga (Oscillatoria woronichinii), a prasinophyte (Testraselmis chuii), two haptophytes (Emiliania huxleyi and Cricosphaera carterae), and a dinoflagellate (Heterocapsa pygmaea). Cultures were incubated for 4 days, and uptake of Tc was periodically determined by ν spectroscopy of filtered and unfiltered samples. All the Tc remained in the water column in all flasks, but none of the species appreciably concentrated the element in either oxidation state. Mean uptake (measured as the fraction retained on filters) for all species was 0.029% for Tc(IV) and 0.023% for Tc(VII), neither of which was significantly different from the uninoculated control cultures. Wet weight concentration factors never exceeded 20 for any species, 3 orders of magnitude lower than previously reported for phytoplankton and Tc. The results indicate that phytoplankton are likely to have negligble influence on the cycling of Tc in marine systems

Effects of CO/sub 2/ and membranes on sporulation in axenic cultures of flax rust. [Melampsora lini

Energy Technology Data Exchange (ETDEWEB)

Boasson, R.; Shaw, M.

1985-01-01

Uredospore production by axenically grown flax rust (Melampsora lini (Ehrenb.) Lev.) was measured as carotenoids (extinction units at 458 nm) per milligram protein. Sporulation was not affected by raising (flushing with 1-5% (v/v) CO/sub 2/ in air) or lowering (KOH well in culture flasks) the level of CO/sub 2/ in the air space above the cultures. Significant (two- to four-fold) increases in sporulation occurred beneath impermeable membranes of parafilm or Saran wrap placed on the surface of young (3 weeks from seeding) mycelial mats for 2 weeks. The stimulatory effect was confined strictly to those areas of the mycelial mats in contact with the membranes. Both Parafilm and Saran wrap were easily and cleanly peeled away from the mycelial mats. Permeable Unipore and HVHP membranes, to which the fungus adhered strongly, did not stimulate sporulation. The fungus did not adhere to Unipore or HVHP membranes treated with silicone or paraffin oil; membranes thus treated stimulated sporulation. The stimulatory effect of membranes on sporulation appears to depend on the nature of the contact between the membrane surface and the mycelium and to be unrelated to the effect of the membranes on the diffusion of gases or other volatile substances. 11 references, 2 figures, 4 tables.

Polyuridylylation and processing of transcripts from multiple gene minicircles in chloroplasts of the dinoflagellate Amphidinium carterae

KAUST Repository

Barbrook, Adrian C.

2012-05-05

Although transcription and transcript processing in the chloroplasts of plants have been extensively characterised, the RNA metabolism of other chloroplast lineages across the eukaryotes remains poorly understood. In this paper, we use RT-PCR to study transcription and transcript processing in the chloroplasts of Amphidinium carterae, a model peridinin-containing dinoflagellate. These organisms have a highly unusual chloroplast genome, with genes located on multiple small \\'minicircle\\' elements, and a number of idiosyncratic features of RNA metabolism including transcription via a rolling circle mechanism, and 3′ terminal polyuridylylation of transcripts. We demonstrate that transcription occurs in A. carterae via a rolling circle mechanism, as previously shown in the dinoflagellate Heterocapsa, and present evidence for the production of both polycistronic and monocistronic transcripts from A. carterae minicircles, including several regions containing ORFs previously not known to be expressed. We demonstrate the presence of both polyuridylylated and non-polyuridylylated transcripts in A. carterae, and show that polycistronic transcripts can be terminally polyuridylylated. We present a model for RNA metabolism in dinoflagellate chloroplasts where long polycistronic precursors are processed to form mature transcripts. Terminal polyuridylylation may mark transcripts with the correct 3′ end. © 2012 Springer Science+Business Media B.V.

Laser damage to marine plankton and its application to checking biofouling and invasion by aquatic species: a laboratory study.

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Nandakumar, Kanavillil; Obika, Hideki; Sreekumari, Kurissery; Utsumi, Akihiro; Ooie, Toshihiko; Yano, Tetsuo

2009-01-01

In this laboratory study, the ability of low-power pulsed laser irradiation to kill planktonic organisms in a flowing water system was examined, thus, to test the possibility of using this technique as a water treatment strategy to reduce biofouling growth in condenser tubes of power plants and to reduce bioinvasion via the ballast water of ships. Two flow rates (4.6 and 9.0 l h(-1)) were tested on three planktonic organisms: two marine centric diatoms viz. Skeletonema costatum and Chaetoceros gracilis and a dinoflagellate, Heterocapsa circularisquama. A low-power pulsed laser irradiation at 532 nm with a fluence of 0.1 J cm(-2) from a frequency-doubled Nd:YAG laser was used as the irradiation source. The laser irradiation resulted in a heavy mortality of the test cells. The mortality observed was >90% for S. costatum and H. circularisqama and >70% for C. gracilis. The results suggest that laser irradiation has the potential to act as a water treatment strategy to reduce biofouling of condenser tubes in power plants as well as to reduce species invasion via the ballast water of ships.

Identification of non-indigenous phytoplankton species dominated bloom off Goa using inverted microscopy and pigment (HPLC) analysis

Science.gov (United States)

Bhaskar, P. V.; Roy, Rajdeep; Gauns, Mangesh; Shenoy, D. M.; Rao, V. D.; Mochemadkar, S.

2011-12-01

An unusual phytoplankton bloom dominated by unidentified green coloured spherical algal cells (˜5μm diameter) and dinoflagellates ( Heterocapsa, Scripsiella and Gymnodinium) was encountered along the coast of Goa, India during 27 and 29 January, 2005. Pigment analysis was carried out using both fluorometric and HPLC methods. Seawater samples collected from various depths within the intense bloom area showed high concentrations of Chl a (up to 106 mg m - 3) associated with low bacterial production (0.31 to 0.52 mg C m - 3 h - 1) and mesozooplankton biomass (0.03 ml m - 3). Pigment analyses of the seawater samples were done using HPLC detected marker pigments corresponding to prasinophytes, dinoflagellates and diatoms. Chlorophyll b (36-56%) followed by peridinin (15-30%), prasinoxanthin (11-17%) and fucoxanthin (7-15%) were the major diagnostic pigments while pigments of cryptophytes and cyanobacteria including alloxanthin and zeaxanthin formed <10%. Although microscopic analysis indicated a decline in the bloom, pheaophytin concentrations in the water column measured by both techniques were very low, presumably due to fast recycling and/or settling rate. The unique composition of the bloom and its probable causes are discussed in this paper.

Holocene history and environmental reconstruction of a Hercynian mire and surrounding mountain landscape based on multiple proxies

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Dudová, Lydie; Hájková, Petra; Opravilová, Věra; Hájek, Michal

2014-07-01

We discovered the first peat section covering the entire Holocene in the Hrubý Jeseník Mountains, representing an island of unique alpine vegetation whose history may display transitional features between the Hercynian and Carpathian regions. We analysed pollen, plant macrofossils (more abundant in bottom layers), testate amoebae (more abundant in upper layers), peat stratigraphy and chemistry. We found that the landscape development indeed differed from other Hercynian mountains located westward. This is represented by Pinus cembra and Larix during the Pleistocene/Holocene transition, the early expansion of spruce around 10,450 cal yr BP, and survival of Larix during the climatic optimum. The early Holocene climatic fluctuations are traced in our profile by species compositions of both the mire and surrounding forests. The mire started to develop as a calcium-rich percolation fen with some species recently considered to be postglacial relicts (Meesia triquetra, Betula nana), shifted into ombrotrophy around 7450 cal yr BP by autogenic succession and changed into a pauperised, nutrient-enriched spruce woodland due to modern forestry activities. We therefore concluded that its recent vegetation is not a product of natural processes. From a methodological viewpoint we demonstrated how using multiple biotic proxies and extensive training sets in transfer functions may overcome taphonomic problems.

Solar PAR and UVR modify the community composition and photosynthetic activity of sea ice algae.

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Enberg, Sara; Piiparinen, Jonna; Majaneva, Markus; Vähätalo, Anssi V; Autio, Riitta; Rintala, Janne-Markus

2015-10-01

The effects of increased photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) on species diversity, biomass and photosynthetic activity were studied in fast ice algal communities. The experimental set-up consisted of nine 1.44 m(2) squares with three treatments: untreated with natural snow cover (UNT), snow-free (PAR + UVR) and snow-free ice covered with a UV screen (PAR). The total algal biomass, dominated by diatoms and dinoflagellates, increased in all treatments during the experiment. However, the smaller biomass growth in the top 10-cm layer of the PAR + UVR treatment compared with the PAR treatment indicated the negative effect of UVR. Scrippsiella complex (mainly Scrippsiella hangoei, Biecheleria baltica and Gymnodinium corollarium) showed UV sensitivity in the top 5-cm layer, whereas Heterocapsa arctica ssp. frigida and green algae showed sensitivity to both PAR and UVR. The photosynthetic activity was highest in the top 5-cm layer of the PAR treatment, where the biomass of the pennate diatom Nitzschia frigida increased, indicating the UV sensitivity of this species. This study shows that UVR is one of the controlling factors of algal communities in Baltic Sea ice, and that increased availability of PAR together with UVR exclusion can cause changes in algal biomass, photosynthetic activity and community composition. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A comparison of morphological and molecular-based surveys to estimate the species richness of Chaetoceros and Thalassiosira (bacillariophyta, in the Bay of Fundy.

Directory of Open Access Journals (Sweden)

Sarah E Hamsher

Full Text Available The goal of this study was to compare the ability of morphology and molecular-based surveys to estimate species richness for two species-rich diatom genera, Chaetoceros Ehrenb. and Thalassiosira Cleve, in the Bay of Fundy. Phytoplankton tows were collected from two sites at intervals over two years and subsampled for morphology-based surveys (2010, 2011, a culture-based DNA reference library (DRL; 2010, and a molecular-based survey (2011. The DRL and molecular-based survey utilized the 3' end of the RUBISCO large subunit (rbcL-3P to identify genetic species groups (based on 0.1% divergence in rbcL-3P, which were subsequently identified morphologically to allow comparisons to the morphology-based survey. Comparisons were compiled for the year (2011 by site (n = 2 and by season (n = 3. Of the 34 taxa included in the comparisons, 50% of taxa were common to both methods, 35% were unique to the molecular-based survey, and 12% were unique to the morphology-based survey, while the remaining 3% of taxa were unidentified genetic species groups. The morphology-based survey excelled at identifying rare taxa in individual tow subsamples, which were occasionally missed with the molecular approach used here, while the molecular methods (the DRL and molecular-based survey, uncovered nine cryptic species pairs and four previously overlooked species. The last mentioned were typically difficult to identify and were generically assigned to Thalassiosira spp. during the morphology-based survey. Therefore, for now we suggest a combined approach encompassing routine morphology-based surveys accompanied by periodic molecular-based surveys to monitor for cryptic and difficult to identify taxa. As sequencing technologies improve, molecular-based surveys should become routine, leading to a more accurate representation of species composition and richness in monitoring programs.

Simultaneous quantification by HPLC of the phenolic compounds for the crude drug of Prunus serotina subsp. capuli.

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Rivero-Cruz, Blanca

2014-08-01

Prunus serotina Ehrenb. subsp. capuli (Cav.) McVaugh (Rosaceae), commonly known as "capulin", is a native North American tree, commercialized and used in folk medicine for the treatment of the hypertension, gastrointestinal illnesses, and cough. This work developed a suitable HPLC method for quantifying the major active constituents of the infusion of P. serotina, the most important preparation consumed by populations around the world. The analytical method was performed using a Fortis-RP column (150 mm × 4.6 mm; film thickness 5 µm). The mobile phase consisted of an isocratic acetate buffer solution (pH 2.7; A) and methanol (B) (65:35 v/v) at a flow rate of 1.0 mL min(-1). The proposed method was applied to the quantification of 1-3 in several samples of the leaves of P. serotina. The results indicated that amounts of 1-3 in the samples analyzed are uniform, and greater amounts of chlorogenic acid (2; 479.9 ± 33.6 µg g(-1), dry matter) along with hyperoside (1; 185.7 ± 55.3 µg g(-1), dry matter) were present. On the other hand, benzaldehyde (3; 118.2 ± 12.1 µg g(-1) dry matter) was found to be in lower concentration. A simple, sensitive, precise, and reproducible HPLC method for the simultaneous quantification of 1-3 in P. serotina was developed and validated. This is the first report on the quantification of 1-3 as active principles, and compound 1 was selected as a marker of P. serotina, which could be useful to guarantee the quality of the crude drug and herbal products.

New Neandertal wrist bones from El Sidrón, Spain (1994-2009).

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Kivell, Tracy L; Rosas, Antonio; Estalrrich, Almudena; Huguet, Rosa; García-Tabernero, Antonio; Ríos, Luis; de la Rasilla, Marco

2018-01-01

Twenty-nine carpal bones of Homo neanderthalensis have been recovered from the site of El Sidrón (Asturias, Spain) during excavations between 1994 and 2009, alongside ∼2500 other Neandertal skeletal elements dated to ∼49,000 years ago. All bones of the wrist are represented, including adult scaphoids (n = 6), lunates (n = 2), triquetra (n = 4), pisiforms (n = 2), trapezia (n = 2), trapezoids (n = 5), capitates (n = 5), and hamates (n = 2), as well as one fragmentary and possibly juvenile scaphoid. Several of these carpals appear to belong to the complete right wrist of a single individual. Here we provide qualitative and quantitative morphological descriptions of these carpals, within a comparative context of other European and Near Eastern Neandertals, early and recent Homo sapiens, and other fossil hominins, including Homo antecessor, Homo naledi, and australopiths. Overall, the El Sidrón carpals show characteristics that typically distinguish Neandertals from H. sapiens, such as a relatively flat first metacarpal facet on the trapezium and a more laterally oriented second metacarpal facet on the capitate. However, there are some distinctive features of the El Sidrón carpals compared with most other Neandertals. For example, the tubercle of the trapezium is small with limited projection, while the scaphoid tubercle and hamate hamulus are among the largest seen in other Neandertals. Furthermore, three of the six adult scaphoids show a distinctive os-centrale portion, while another is a bipartite scaphoid with a truncated tubercle. The high frequency of rare carpal morphologies supports other evidence of a close genetic relationship among the Neandertals found at El Sidrón. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spatial and temporal trends of freshwater mussel assemblages in the Meramec River Basin, Missouri, USA

Science.gov (United States)

Hinck, Jo Ellen; McMurray, Stephen E.; Roberts, Andrew D.; Barnhart, M. Christopher; Ingersoll, Christopher G.; Wang, Ning; Augspurger, Tom

2012-01-01

The Meramec River basin in east-central Missouri has one of the most diverse unionoid mussel faunas in the central United States with >40 species identified. Data were analyzed from historical surveys to test whether diversity and abundance of mussels in the Meramec River basin (Big, Bourbeuse, and Meramec rivers, representing >400 river miles) decreased between 1978 and 1997. We found that over 20y, species richness and diversity decreased significantly in the Bourbeuse and Meramec rivers but not in the Big River. Most species were found at fewer sites and in lower numbers in 1997 than in 1978. Federally endangered species and Missouri Species of Conservation Concern with the most severe temporal declines were Alasmidonta viridis, Arcidens confragosus, Elliptio crassidens, Epioblasma triquetra, Fusconaia ebena, Lampsilis abrupta, Lampsilis brittsi, and Simpsonaias ambigua. Averaged across all species, mussels were generally being extirpated from historical sampling sites more rapidly than colonization was occurring. An exception was one reach of the Meramec River between river miles 28.4 and 59.5, where mussel abundance and diversity were greater than in other reaches and where colonization of Margaritiferidae, Lampsilini, and Quadrulini exceeded extirpation. The exact reasons mussel diversity and abundance have remained robust in this 30- mile reach is uncertain, but the reach is associated with increased gradients, few long pools, and vertical rock faces, all of which are preferable for mussels. Complete loss of mussel communities at eight sites (16%) with relatively diverse historical assemblages was attributed to physical habitat changes including bank erosion, unstable substrate, and sedimentation. Mussel conservation efforts, including restoring and protecting riparian habitats, limiting the effects of in-stream sand and gravel mining, monitoring and controlling invasive species, and protecting water quality, may be warranted in the Meramec River basin.

Effects of Nitrogen Availability and Form on Phytoplankton Growth in a Eutrophied Estuary (Neuse River Estuary, NC, USA).

Science.gov (United States)

Cira, Emily K; Paerl, Hans W; Wetz, Michael S

2016-01-01

Nitrogen availability and form are important controls on estuarine phytoplankton growth. This study experimentally determined the influence of urea and nitrate additions on phytoplankton growth throughout the growing season (March 2012, June 2011, August 2011) in a temperate, eutrophied estuary (Neuse River Estuary, North Carolina, USA). Photopigments (chlorophyll a and diagnostic photopigments: peridinin, fucoxanthin, alloxanthin, zeaxanthin, chlorophyll b) and microscopy-based cell counts were used as indicators of phytoplankton growth. In March, the phytoplankton community was dominated by Gyrodinium instriatum and only fucoxanthin-based growth rates were stimulated by nitrogen addition. The limited response to nitrogen suggests other factors may control phytoplankton growth and community composition in early spring. In June, inorganic nitrogen concentrations were low and stimulatory effects of both nitrogen forms were observed for chlorophyll a- and diagnostic photopigment-based growth rates. In contrast, cell counts showed that only cryptophyte and dinoflagellate (Heterocapsa rotundata) growth were stimulated. Responses of other photopigments may have been due to an increase in pigment per cell or growth of plankton too small to be counted with the microscopic methods used. Despite high nitrate concentrations in August, growth rates were elevated in response to urea and/or nitrate addition for all photopigments except peridinin. However, this response was not observed in cell counts, again suggesting that pigment-based growth responses may not always be indicative of a true community and/or taxa-specific growth response. This highlights the need to employ targeted microscopy-based cell enumeration concurrent with pigment-based technology to facilitate a more complete understanding of phytoplankton dynamics in estuarine systems. These results are consistent with previous studies showing the seasonal importance of nitrogen availability in estuaries, and also

Remarkable sequence similarity between the dinoflagellate-infecting marine girus and the terrestrial pathogen African swine fever virus

Directory of Open Access Journals (Sweden)

Claverie Jean-Michel

2009-10-01

Full Text Available Abstract Heterocapsa circularisquama DNA virus (HcDNAV; previously designated as HcV is a giant virus (girus with a ~356-kbp double-stranded DNA (dsDNA genome. HcDNAV lytically infects the bivalve-killing marine dinoflagellate H. circularisquama, and currently represents the sole DNA virus isolated from dinoflagellates, one of the most abundant protists in marine ecosystems. Its morphological features, genome type, and host range previously suggested that HcDNAV might be a member of the family Phycodnaviridae of Nucleo-Cytoplasmic Large DNA Viruses (NCLDVs, though no supporting sequence data was available. NCLDVs currently include two families found in aquatic environments (Phycodnaviridae, Mimiviridae, one mostly infecting terrestrial animals (Poxviridae, another isolated from fish, amphibians and insects (Iridoviridae, and the last one (Asfarviridae exclusively represented by the animal pathogen African swine fever virus (ASFV, the agent of a fatal hemorrhagic disease in domestic swine. In this study, we determined the complete sequence of the type B DNA polymerase (PolB gene of HcDNAV. The viral PolB was transcribed at least from 6 h post inoculation (hpi, suggesting its crucial function for viral replication. Most unexpectedly, the HcDNAV PolB sequence was found to be closely related to the PolB sequence of ASFV. In addition, the amino acid sequence of HcDNAV PolB showed a rare amino acid substitution within a motif containing highly conserved motif: YSDTDS was found in HcDNAV PolB instead of YGDTDS in most dsDNA viruses. Together with the previous observation of ASFV-like sequences in the Sorcerer II Global Ocean Sampling metagenomic datasets, our results further reinforce the ideas that the terrestrial ASFV has its evolutionary origin in marine environments.

Effects of Nitrogen Availability and Form on Phytoplankton Growth in a Eutrophied Estuary (Neuse River Estuary, NC, USA)

Science.gov (United States)

Paerl, Hans W.; Wetz, Michael S.

2016-01-01

Nitrogen availability and form are important controls on estuarine phytoplankton growth. This study experimentally determined the influence of urea and nitrate additions on phytoplankton growth throughout the growing season (March 2012, June 2011, August 2011) in a temperate, eutrophied estuary (Neuse River Estuary, North Carolina, USA). Photopigments (chlorophyll a and diagnostic photopigments: peridinin, fucoxanthin, alloxanthin, zeaxanthin, chlorophyll b) and microscopy-based cell counts were used as indicators of phytoplankton growth. In March, the phytoplankton community was dominated by Gyrodinium instriatum and only fucoxanthin-based growth rates were stimulated by nitrogen addition. The limited response to nitrogen suggests other factors may control phytoplankton growth and community composition in early spring. In June, inorganic nitrogen concentrations were low and stimulatory effects of both nitrogen forms were observed for chlorophyll a- and diagnostic photopigment-based growth rates. In contrast, cell counts showed that only cryptophyte and dinoflagellate (Heterocapsa rotundata) growth were stimulated. Responses of other photopigments may have been due to an increase in pigment per cell or growth of plankton too small to be counted with the microscopic methods used. Despite high nitrate concentrations in August, growth rates were elevated in response to urea and/or nitrate addition for all photopigments except peridinin. However, this response was not observed in cell counts, again suggesting that pigment-based growth responses may not always be indicative of a true community and/or taxa-specific growth response. This highlights the need to employ targeted microscopy-based cell enumeration concurrent with pigment-based technology to facilitate a more complete understanding of phytoplankton dynamics in estuarine systems. These results are consistent with previous studies showing the seasonal importance of nitrogen availability in estuaries, and also

Uso combinado de radiación UV-C y biorecubrimiento de quitosán con aceites esenciales para el control de hongos en papaya Maradol

Directory of Open Access Journals (Sweden)

Alfredo Vázquez-Ovando

2018-05-01

Full Text Available Resumen La antracnosis y pudrición blanda en frutos de papaya provocan deterioro de la calidad, así como grandes pérdidas durante el manejo postcosecha. El uso de estrategias individuales para el control de enfermedades resulta poco eficiente. Por lo anterior, en el presente estudio se evaluó el efecto sinérgico de varias estrategias de control sobre la incidencia de enfermedad causada por la inoculación de esporas de los hongos Colletotrichum gloeosporioides (Penz. y Rhizopus stolonifer (Ehrenb. en papaya var. Maradol. Se evaluaron tratamientos resultantes de la combinación del uso de biorecubrimientos compuestos elaborados con quitosán (15 g L-1 adicionadas con aceites esenciales (AE de clavo, tomillo y/o lima (5 ó 10 mL L-1 de cada AE y tres dosis de irradiación UV-C (0.97 kJ·m-2, 2 kJ·m-2 y 2.88 kJ·m-2, aplicados a las 12, 24 y 48 h post-inoculación de esporas de los fitopatógenos. El tratamiento donde se combinó el biorecubrimiento adicionado con 10 mL L-1 de AE de clavo y 10 mL L-1 de AE de tomillo y una dosis de irradiación UV-C de 2.88 kJ m-2 (B1T92 aplicado a las 24 h post-inoculación de esporas, logró mantener la incidencia de enfermedad (para ambos hongos evaluados a valores menores de 25% durante nueve días de almacenamiento a temperatura de 28 ± 3 °C y 80% de HR. Este mismo tratamiento redujo la velocidad específica de la enfermedad, con valores de 0.549 y 0.029 d-1 para C. gloeosporioidesy R. stolonifer, respectivamente. Otros tratamientos (B2T62, B1T34, B1T34, B1T94 presentaron actividad antifúngica (valores promedio de incidencia de 35% durante todo el almacenamiento para R. stolonifer. Los resultados de este trabajo demuestran que el efecto sinérgico del uso de biorecubrimientos de quitosán con aceites esenciales y energía UV-C controla el desarrollo de hongos causantes de antracnosis y pudrición blanda en frutos de papaya Maradol.

Synoptic events force biological productivity in Patagonian fjord ecosystems

Science.gov (United States)

Daneri, Giovanni

2016-04-01

an extremely productive bloom of the dinoflagellate Heterocapsa sp. in July 2014, after the passage of a synoptic low pressure front provided, for the first time, strong evidence that phytoplankton blooming in the Patagonian fjord ecosystems is controlled by synoptic processes and that they are not limited by light as previously reported. This research was funded by COPAS Sur-Austral (PFB-31) and FONDECYT 1131063

Possible importance of algal toxins in the Salton Sea, California

Science.gov (United States)

Reifel, K.M.; McCoy, M.P.; Rocke, T.E.; Tiffany, M.A.; Hurlbert, S.H.; Faulkner, D.J.

2002-01-01

In response to wildlife mortality including unexplained eared grebe (Podiceps nigricollis) die-off events in 1992 and 1994 and other mortality events including large fish kills, a survey was conducted for the presence of algal toxins in the Salton Sea. Goals of this survey were to determine if and when algal toxins are present in the Salton Sea and to describe the phytoplankton composition during those times. A total of 29 samples was collected for toxicity analysis from both nearshore and midlake sites visited biweekly from January to December 1999. Dinoflagellates and diatoms dominated most samples, but some were dominated by a prymnesiophyte (Pleurochrysis pseudoroscoffensis) or a raphidophyte (Chattonella marina). Several types of blooms were observed and sampled. The dinoflagellate Gyrodinium uncatenum formed an extensive, dense (up to 310 000 cells ml−1) and long-lasting bloom during the winter in 1999. A coccolithophorid, Pleurochrysis pseudoroscoffensis, occurred at high densities in surface films and nearshore areas during the spring and summer of 1999. These surface films also contained high densities of one or two other species (an unidentified scrippsielloid, Heterocapsa niei, Chattonella marina). Localized blooms were also observed in the Salton Sea. An unknown small dinoflagellate reached high densities (110 000 cells ml−1) inside Varner Harbor, and an unidentified species of Gymnodinium formed a dense (270 000 cells ml−1) band along part of the southern shoreline during the summer. Three species known to produce toxins in other systems were found. Protoceratium reticulatum (=Gonyaulax grindleyi) and Chattonella marina were found in several samples taken during summer months, and Prorocentrum minimum was found in low densities in several samples. Extracts of most samples, including those containing known toxic species, showed a low level (Salton Sea, no evidence gathered in this study suggests that algal toxins are present

Biological Ice Nuclei: They are Everywhere, What are Their Roles? (Invited)

Science.gov (United States)

Schnell, R. C.

2009-12-01

Biological ice nuclei active at temperatures warmer than -2C were first observed in the late 1960s associated with decaying grass and tree leaves; discovered more by accident than in a planned experiment. The active component of the decaying leaves was subsequently found to be produced by a few living bacteria, the two most ubiquitous being strains of P. syringae and E. herbicola. The active bacterial ice nuclei are easily deactivated by anaerobic, chemical and heat stresses. The same grass and tree leaves, when well decayed, generally contain less active ice nuclei (threshold temperatures of -5C to - 6C) in the 0.1 micron diameter range compared to the larger (1 micron) bacteria associated ice nuclei. The well decayed leaf litter ice nuclei are stable over a wide range of stresses and time; some samples of leaf derived nuclei stored at room temperature have exhibited the same ice nucleus concentration for over 30 years. Fungi also have active ice nuclei that are stable over many decades. Active ice nuclei are found in marine waters associated with plankton, and are produced by at least one marine dinoflagellate (Heterocapsa niei) that expresses ice nucleus activity almost as warm as terrestrial bacteria ice nuclei. Living ice nucleus bacteria have been found in marine fogs far at sea, in precipitation in Antarctica as well as over many continental areas, in air in the high Arctic, on vegetation around the world, on remote ice bound islands, and growing on and inside water storing vegetation on isolated tropical mountain peaks. But why? What is the evolutionary advantage for the ice nucleus gene to be expressed in such a wide range of environments, by greatly different species? There is an energy cost for bacteria and fungi to support the ice gene, so it probably is not a genetic anomaly. Possibly the ice nuclei play many roles? These could include damaging plants to acquire a food source, an aid in survival and dispersal in clouds, initiation of precipitation to