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751.
On the occasion of the anniversary a recollection is given of the history of the discovery of electron diffraction.
相似文献752.
Sylvie Lapègue Inès Ben Salah Frederico M. Batista Serge Heurtebise Lassad Neifar Pierre Boudry 《Marine Biology》2006,150(1):103-110
Despite the economic importance of oysters due to the high aquaculture production of several species, the current knowledge of oyster phylogeny and systematics is still fragmentary. In Europe, Ostrea edulis, the European flat oyster, and Ostreola stentina, the Provence oyster or dwarf oyster, are both present along the European and African, Atlantic and Mediterranean, coasts. In order to document the relationship not only between O. stentina and O. edulis, but also with the other Ostrea and Ostreola species, we performed a sequence analysis of the 16S mitochondrial fragment (16S rDNA: the large subunit rRNA-coding gene) and the COI fragment (COI: cytochrome oxidase subunit I). Oysters were sampled from populations in Portugal (two populations), Tunisia (two populations) and Morocco (one population), identified as O. stentina on the basis of shell morphological characters. Our data supported a high degree of differentiation between O. stentina and O. edulis and a close relationship between O. stentina and both Ostrea aupouria (from New Zealand) and Ostreola equestris (from Mexico Gulf/Atlantic). The status of this geographic disjunction between these closely related species is discussed. Furthermore, although identified in a separate genus Ostreola by Harry (Veliger 28:121–158, 1985), our molecular data on O. stentina, together with those available for the other two putative congeneric species, O. equestris and Ostreola conchaphila, would favour incorporation of Ostreola in Ostrea. Finally, a PCR-RFLP approach allowed the rapid identification of O. edulis and O. stentina. 相似文献
753.
This study investigates the feeding behaviour of the precious red coral Corallium rubrum on bacterioplankton. The effects of flow rate, prey concentration, and seawater temperature were tested. The results obtained
show that C. rubrum was able to prey on both pico- and nanoplankton cells. Flagellates constituted the major bacterioplankton food source in
terms of carbon and nitrogen, representing from 43 to 70% of the C and N ingested. Flow speed (2, 6, and 11 cm s−1) had no effect on grazing rates, maybe due to the small size of the ingested particles. Conversely, feeding rates increased
with prey concentration and seawater temperature. There was a doubling of the picoplankton ingestion rate for a sixfold increase
in its concentration. The ingestion of autotrophic flagellates, however, increased at the same time as their concentration,
indicating a preference for this type of food. Considering the range of concentrations typically found in the Ligurian Sea,
the ingestion of pico- and nanoplankton brings 148 ng C polyp−1 day−1 and 28 ng N polyp−1 day−1. This type of food represents only ca. 4.5% of the total carbon gained by C. rubrum from the different sources, but might be the most important in terms of nitrogen, phosphorus, and other essential elements. 相似文献
754.
Hélène Hégaret Gary H. Wikfors Philippe Soudant Christophe Lambert Sandra E. Shumway Jean Baptiste Bérard Patrick Lassus 《Marine Biology》2007,152(2):441-447
The possible effect of Alexandrium spp. containing paralytic shellfish poisoning (PSP) toxins on the hemocytes of oysters was tested experimentally. In one
trial, eastern oysters, Crassostrea virginica Gmelin, were exposed to bloom concentrations of the sympatric dinoflagellate, Alexandrium
fundyense Balech, alone and in a mixture with a non-toxic diatom, Thalassiosira weissflogii (Grun) Fryxell et Hasle. Subsequently, another experiment exposed Pacific oysters, Crassostrea gigas Thunberg, to a mixed suspension of the sympatric, toxic species Alexandrium catenella (Whedon et Kofoid) Balech, with T. weissflogii. Measurements of numbers of oyster hemocytes, percentages of different cell types, and functions (phagocytosis, reactive
oxygen species (ROS) production, and mortality) were made using flow-cytometry. During and after exposure, almost no significant
effects of Alexandrium spp. upon hemocyte numbers, morphology, or functions were detected, despite observations of adductor-muscle paralysis in
C. virginica and measured toxin accumulation in C. gigas. The only significant correlation found was between toxin accumulation at one temperature and higher numbers of circulating
live and dead hemocytes in C. gigas. The PSP toxins are known to interfere specifically with sodium-channel function; therefore, the finding that the toxins
had no effect on measured hemocyte functions suggests that sodium-channel physiology is not important in these hemocyte functions.
Finally, because oysters were exposed to the living algae, not purified toxins, there was no evidence of bioactive compounds
other than PSP toxins affecting hemocytes in the two species of Alexandrium studied. 相似文献
755.
D. Rivière 《Marine Biology》1983,75(1):19-23
Four copepod species (Acartia clausi, Centropages typicus, Temora stylifera, Calanus helgolandicus) from the northwest Mediterranean were subjected to electrophoresis on polyacrylamide gel in an attempt to distinguish specific biochemical characteristics for each species. Enzymograms of 5 enzymes were studied: esterases, leucine aminopeptidase, alkaline phosphatase, malate dehydrogenase and the malic enzyme. Marked interspecific differences were revealed, enabling specific biochemical identities to be established which can be useful as taxonomic criteria in the same way as morphological characteristics. The study was performed during different seasons in 1980. 相似文献
756.
Females of the Norway lobster Nephrops norvegicus (L.) incubate their eggs under the abdomen for a period of several months. We estimated the individual fecundity of N. norvegicus (1) before spawning, and (2) at the end of the incubation period. From these two relationships, we then calculated the average egg loss. Egg loss seems to be relatively higher for small females than for large ones. The mean egg loss estimated for the Bay of Biscay (45%) differs from the only other existing value (75%) calculated by other authors for Portuguese waters. Egg loss may regulate stock-density, and may be a mechanism intervening in stock-recruitment. In order to estimate the fecundity per recruit, fecundity at the end of the incubation period must be used: this takes into account the rate of egg loss as a function of female length.
Contribution No. 721, du Centre Océanologique de Bretagne 相似文献
Contribution No. 721, du Centre Océanologique de Bretagne 相似文献
757.
Maria do Socorro S. Pereira Eduardo Winter Jose Roberto Guimarães Susanne Rath Anne Hélène Fostier 《Environmental Chemistry Letters》2007,5(3):137-141
Here, we show a fast and sensitive method for the determination of inorganic arsenic in natural waters using differential
pulse cathodic stripping voltammetry. All the arsenite determinations were done in 2.0 mol L−1 HCl + 3.15 × 10−4 mol L−1 Cu(II) supporting electrolyte. 1 × 10−3 mol L−1 sodium thiosulphate was used as As(V) reducing agent. The detection limit was 0.5 μg L−1 for both species. The method has been applied to water samples collected in an arsenic-contaminated region of Brazil, in
particular, to verify the efficiency of the solar oxidation and removal of arsenic process applied to these waters. 相似文献
758.
Vincenzo Augugliaro Claudio Baiocchi Alessandra Bianco Prevot Elisa García-Lpez Vittorio Loddo Sixto Malato Giuseppe Marcí Leonardo Palmisano Marco Pazzi Edmondo Pramauro 《Chemosphere》2002,49(10)
The photodegradation of two common and very stable azo-dyes, i.e. methyl-orange (C14H14N3SO3Na) and orange II (C16H11N2SO4Na), is reported. The photocatalytic oxidation was carried out in aqueous suspensions of polycrystalline TiO2 irradiated by sunlight. Compound parabolic collectors, installed at the “Plataforma Solar de Almería” (PSA, Spain) were used as the photoreactors and two identical reacting systems allowed to perform photoreactivity runs for the two dyes at the same time and under the same irradiation conditions. The disappearance of colour and substrates together with the abatement of total organic carbon content was monitored. The main sulfonate-containing intermediates were found to be in lower number in respect to those obtained under artificial irradiation. In particular there were no more evidence of the presence of hydroxylated transients. The dependence of dye photooxidation rate on: (i) substrate concentration; (ii) catalyst amount; and (iii) initial pH was investigated. The influence of the presence of strong oxidant species (H2O2, S2O82−) and some ions (Cl−, SO42−) on the process was also studied. 相似文献
759.
760.
Marguerite Miguet Julien Thevenon Vincent Laugel Mathilde Lefebvre Aurélie Bourchany Jean-Baptiste Rivière Yannis Duffourd Elise Schaefer Maria Cristina Antal Rosalie Abida Anne-Sophie Weingertner Valérie Kremer Pierre Vabres Fanny Morice-Picard Marie Gonzales Dan Lipsker Sylvie Fraitag Jean-Louis Mandel Jamel Chelly Hélène Dollfus Laurence Faivre Christel Thauvin-Robinet Nadège Calmels Salima El Chehadeh 《黑龙江环境通报》2016,36(13):1276-1279