Nouvelles formulations des regles ecologiques connues sous le nom de reegle de Bergmann et loi de Jordan: Amendments of the ecological rules known as Bergmann's and Jordan's rules

Measurements of populations of planktonic and micronektonicspecies from the Atlanto-mediterranean region (about 10,000specimens) have lead to improvements in Bergmann's rule relatingto the increase in size with latitude. There are three cases : Mediterranean specimens may be smaller(e.g. the mysid Eucopia hansent), equal to (e.g. the decapodcrustacean Gennadas elegans) or larger than Atlantic ones (e.g.the thecosomatous genus Cymbulia). All the species in the last group have their principal distributionin warm ocean waters. In the Atlantic, tropical species (e.g.the euphausiid Euphausia gibboides) decrease in size in thenorthern parts of their range while temperate species (e.g.the decapod crustacean Sergesles corniculum) decrease in sizetowards both the pole and the equator. The comparison with the number of vertebrae of fish, which increasesas does the size according to Jordan's rule, is interesting:though correct for cold water species (e.g. Merlucdus merluccius),this rule cannot be applied to warm water species (e.g. Merlucciussenegalensis). Thus, these rules must be corrected like this:- "a species reachesits maximal size in high, intermediate or low latitudes of itsarea if it has a boreal, temperate or tropical distribution"; - "the number of vertebrae increases with latitude for borealfish and decreases for tropical ones".     

Conditions de formation d'agr?gats de chlorophylle {alpha} dans des solvants polaires aqueux: polarit? du milieu

The absorbance and emission spectroscopy of chlorophyll a (10^–5M) in water-miscible alcohols, acetone and dioxane were studiedto determine the properties of the chloroplast membranes whichsupport the aggregation of chlorophyll in vivo. It appears thatthe formation of the chlorophyll aggregates is closely dependenton the polarity of their molecular environment. (Received April 16, 1974; )     

Sur une nouvelle applicaton de la theorie de P information a la description des series chronologiques planctoniques

Corrélations simples (r) et pondérées (r_p)entre S. setosa (trois stades cumulés), S. minima etS. inflata (stade 1), S. bipunctata, et les quatre paramétreshydrologiques retenus. ^aSeuil de signification 5%. ^bSeuil designification 1%     

Anomalies morphologiques chez le genre Acartia (Crustacea, Copepoda): description et essai de quantification

We have found morphological anomalies in the fifth pair of thoraciclegs of female Acartic clausi and A. discaudata, sampled inthe harbour at Dunkirk (France), in the eastern English Channeland in the North Sea. The percentage of anomalies in A. clausi(<1%) is not significantly different between polluted andnon-polluted sites. The frequency of anomalies is on the otherhand clearly higher in A. bilfilosa (>20%) than in A. clausi.     

Hugo de Vries and the Development of Seed Aging Theory

Although work published in 1901 by de Vries has helped shapeour current understanding of the relationship between seed agingand genetic mutation, it has been fundamentally misinterpreted.Upon sowing 5 year-old Oenothera erythrosepala seed, de Vriesobtained an emergence of about 1 per cent. A relatively highproportion of the seedlings (about 40 per cent) displayed mutantphenotypes, mostly albida or lata. De Vries concluded that thesephenotypes, which were already present to a minor extent (about1 per cent) in unaged seed lots, were more resistant to agingthan the erythrosepala norm. Later opinion has dismissed DeVries' hypothesis, contending instead that the mutant phenotypesarose as a consequence of seed aging. A reconsideration of thesedata suggests that the De Vries' explanation remains more convincing;paradoxically, his work on seed aging has been influential becauseit has been consistently misunderstood. Mutation, Oenothera, seed aging     

Observations sur la Presence de Certains Lamellibranches Lithophages Fossiles du Miocene dans le Sud-Est de l'Europe et dans la Mer Noire

Dans le Miocène moyen du Sud-Est de l'Europe on rencontretrès rarement des exemplaires fossiles de lamellibrancheslithophages, quelques-uns de ceux-ci appartenant au genre Lithophagaet d'autres au Pholas, Clavagella, Saxicava, Petricola, et Barnea.Certaines especes de Pholas et de Barnea sont rélativementsouvent rencontrees non seulement dans le Miocène moyen(etage Tortonien), mais aussi dans le Miocène supérieur(étage Sarmatien). En génèral ces espèces se rencontrent surun substrat calcaire. Å la fin du Miocène les espècesde lamellibranches fossiles lithophages disparaissent du basinde la Mer Noire, a cause que celui-ci est devenu un basin d'eaudouce. Mais, dans le temps actuel trois espèces de lamellibrancheslithophages vivent aussi dans la Mer Noire, venues dans le Quaternairede la Mer Mediterranee. C'est-à-dire: Pholas dactylusL., Barnea Candida var. pontica Mil., qui vivent sur un substratformé surtout de marnes argileuses ou de marnes calcaires.Sur un substrat de grès dures calcaire se rencontre presqueexclusivement Petricola lithophaga Retzius, sur la plateformerocheuse du sud de Constantza (Roumanie).     

Vieillissement de l'appareil photosynth?tique I. Effet synergique de la lumi?re et du vieillissement in vitro sur les changements de volume de chloroplastes isol?s d'?pinard

In view of the difficulty of studying all of the aspects ofageing of the photosynthetic apparatus in vivo and of the actionof light upon this phenomenon, the consequences of chloroplastageing were investigated in vitro, especially on the volumeof these organelles. It was found that at 20?C in a Tris-NaCl medium, chloroplastswelling occurred slowly in the dark for the 6 hr experimentalperiod, while it was activated in the light, with an optimumafter 90 min. The most characteristic feature of these 2 curvesis that they cross each other after 5 hr, indicating that, independentof the previous treatments (dark or light), the chloroplastsin vitro reach the same volume after a few hours. Special attentionwas devoted to the pH effect. In dark and light conditions,swelling was found to be maximum at pH 7.5 to 8.5 and was independentof the buffer used. There was no major difference between swellingin Tris and Tricine. A marked depression in the chloroplastvolume was observed at pH 4.5 in the dark and at pH 5.5 in thelight. Simultaneous with the swelling phenomenon, the capacity of chloroplaststo carry out light-dependent shrinkage diminished. There wasa striking parallelism between swelling rate and loss of chloroplastshrinkage capacity. The action of light is synergetic on boththese processes in that it accelerated to the same extent boththe dark-swelling and the inhibition of light-dependent shrinkingin chloroplasts incubated in the dark. (Received May 24, 1969; )     

Sur quelques zooplanctontes abondants dans l'upwelling de Cabo Frio (Bresil)

On some zooplankters common in the Cabo Frio (Brazil) upwelling.In the waters off Cabo Frio zooplankton maxima are observedbetween February and April, which is the period of upwellingoccurrence. Copepods are highly diversified; we identified 96species at a single collecting station during one year. In summerCalanoides carinatus, Paracalanus parvus and Oncea media areabundant, whereas we observed dominance of Temora stylifera,Clausocalanus furcatus, C. arcuicomis, Oithona plumifera andgreat quantity of Creseis acicula during winter. Chaetognatha(Sagitta enflata), Appendicularia (Oikopleura longicauda), Ostracoda(Conchoecia spp.) and Pteropoda (Limacina sp.) are permanentthroughout the year, and maximum in summer. The vertical distributionof zooplankton depends on the hydrological structure, i.e. natureof the water mass and degree of mixing between different waters.Brazil current water, with low quantity of organisms and dominanceof copepods (Clausocalanus furcatus, Mecynocera clausi, Corycaeidae,Oithonidae, Oncaeidae) accompanied by Evadne spinifera and Lucifertypicus. South Atlantic Central Water (upwelling water) characterizedby rare deep copepods and abundance of Calanoides carinatusand Ctenocalanus vanus which are excellent indicator speciesfor upwelling occurrence. Coastal water, with low salinity,where some species with brackish affinity are observed, likeOithona ovalis and Podon polyphemoides.     

Red tide assemblage formation in an estuarine upwelling ecosystem: Ria de Vigo

Red tides are conspicuous in the upwelling system of Galicia(NW Iberian Peninsula). At present, there are conflicting hypothesesabout the generation site of these phytoplankton assemblages.It is interesting to know whether the rias can be sites of redtide formation or if they act only as accumulation sites ofpopulations advected from shelf waters. A study in the Ra deVigo, carried out during late September 1990, showed the developmentof a red tide assemblage, composed of Alexandrium affinis, Ceraiiumfusus and Gymnodinium catenaium, during a 2 week upwelling-downwellingcycle. Growth occurred at the bottom of the thermocline-topof the nutricline. Above this assemblage, a diatom assemblage(large diatoms) was blooming. Prior to the formation of thered tide, a subsurface chlorophyll maximum made up of smalldiatoms (Nilzschia f. seriaia, Chaeloceros socialis), smallflagellates (<30 µm) and small gymnodinid forms (<30µm) was observed. In the nutrient-depleted upper layer,several autotrophic and large heterotrophic dinoflagellatesdominated. It is suggested that the ratio between the velocityof upward water movement and the depth of the stratified upperlayer (flushing rate, day^–1) is the critical parameterwhich triggers active phytoplankton growth. It can be concludedthat upward water velocities of {small tilde}2.5 m day^–1and a stratified upper layer of 10 m depth (flushing rate 0.25day^–1) are the main physical constraints for red tidedevelopment.     

Strategies d'adaptation photosynthetique chez des diatomees des I'Ocean Antarctique: variations du nombre et de la talile des unites photosynthetiques

Les diatomes Nitzschia turgiduloides et Chaetoceros deflandrei,rcoltes en fvrier–Mars 1980 dans le secteur indiende l'Ocan Antarctique, ont t maintenues en culture au laboratoire,sous des intensits himineuss variant de 140 2 µE m^–2s^–2. The production versus intensite lumineuse, tabliespar cellule et par unit de chlorophylle a, suggrent, selonla mthode de Richardson et al. (1983), une adaptation des espcesantarctiques la lumire par variation de la taille (estimepar la valeur I_k) et du nombre (volution de la pente initiale) des units photosynthtiques. Au plan ecologique, les valeursdes paramtres photosynthetiques en lumire Bmitante et en lumiresaturante sont faibles, caractristiques des algues ‘d'ombre’:concentration en chlorophylle a et productivit par celluleplus fortes quand les espces sont acclimates a des faiblesintensites lumineuses. Ce travail met ainsi en vidence I'importancedu facteur lumineux par rapport la basse temprature sur laproduction primaire de l'Ocan Antarctique.     

Robust accurate identification of peptides (RAId): deciphering MS2 data using a structured library search with de novo based statistics

Motivation: The key to MS -based proteomics is peptide sequencing.The major challenge in peptide sequencing, whether library searchor de novo, is to better infer statistical significance andbetter attain noise reduction. Since the noise in a spectrumdepends on experimental conditions, the instrument used andmany other factors, it cannot be predicted even if the peptidesequence is known. The characteristics of the noise can onlybe uncovered once a spectrum is given. We wish to overcome suchissues. Results: We designed RAId to identify peptides from their associatedtandem mass spectrometry data. RAId performs a novel de novosequencing followed by a search in a peptide library that wecreated. Through de novo sequencing, we establish the spectrum-specificbackground score statistics for the library search. When thedatabase search fails to return significant hits, the top-rankingde novo sequences become potential candidates for new peptidesthat are not yet in the database. The use of spectrum-specificbackground statistics seems to enable RAId to perform well evenwhen the spectral quality is marginal. Other important featuresof RAId include its potential in de novo sequencing alone andthe ease of incorporating post-translational modifications. Availability: Programs implementing the methods described areavailable from the authors on request. Contact: yyu{at}ncbi.nlm.nih.gov Supplementary information: ftp://ftp.ncbi.nih.gov/pub/yyu/Proteomics/MSMS/RAId/MSMS_bioinfo_supp.pdf     

La reproduction de Temora stylifera: ses implications anatomiques en relation avec le facteur 'nutrition'

The culture of copepods under different feeding regimes hasallowed us to determine the effects of food availability onegg laying. In Temora stylifera spawning appears to be modifiedby the food resources of the adult. Conditions encountered duringdevelopment have little effect on spawning. The life span offemales is reduced by high food availability. In such casesthe sex organs are hypertrophied, the oviducts being distendedby the large oocytes. The ovary is little affected by changesin food availability, while the size of the oviducts variesin relation to feeding. The size of the genital system is reducedin older females. Variations in food concentration induce variationsof several days in the time required for egg laying. A rapidmaturation of the oocytes, combined with nutrition and the availabilityof food permits Temora stylifera to optimize egg laying.     

Ecologie alimentaire de Cyclothone braueri Jespersen et Taning, 1926 (Gonostomatidae) en mer Ligure, Mediterranee occidentale

Stomach contents of 4557 specimens of Cyclothone braueri wereanalyzed. Specimens were captured between 300 and 900 m depth,during November 1980 through December 1981. Results showed thatthis species is a carnivore that feeds mainly on zooplanktonorganisms, of wide vertical distribution, comprising about 38prey items. Most important preys were Copepods' (80%) and Ostracods(12%). Other minor items were euphausid larvae, amphipods anddecapod crustaceans. Dominant prey species was Pleuromamma gracilis,and in minor proportion, Euchaeta marina, Chiridius poppei,and Calanus helgolandicus. The emptiness coefficient was quitehigh (V = 72.6%), with significant differences (P < 0.05)between sexes: V(males) = 81%, V(females) = 71%; between depths:V(at 400 m) = 63%, V(at 900 m) = 79%, and between seasons: V(autumn)= 80%, V(winter) = 60%. Nous avons analysé les contenus stomacaux de 4557 spécimensde Cyclothone braueri capturés entre 300 et 900 m deprofondeur, pendant la période comprise entre novembre1980 et décembre 1981. Le contenu stomacal montre quele régime alimentaire de cette espéce est carnivoreconstitué par 38 sortes de proies, appartenant fondamentalementaux copépodes (80%) et ostracodes (12%). En mondre proportionon trouvait de larves d'euphausiacés, amphipodes et crustacésdécapodes. L'espèce-proie dominante fut Pleuromammagracilis, suivi de loin par Euchaeta marina, Chiridius poppeiet Calanus helgolandicus. La plupart des espèces proiessont des organismes zooplanctoniques d'une vaste distributionverticale. Le coefficient de vacuité est tres élevé(V = 72.6%), présentant des variations significatives(p << 0.05) en fonction du sexe (V mâles = 81% etV femelles = 71%), de la profondeur de pêche (V = 63%à 400 m et V = 79% à 900 m), et de la saison del'année (V = 80% en automne et V = 60% en hiver).     

Effets des fluctuations rapides de la lumiere sur la photosynthese du phytoplancton

[¹⁴C]-assimilation rates were measured on cultures of two unicellulargreen algae (Chlamydomonas sp. and Oocystis sp.) as a functionof light intensities (saturation curves), under steady lightand also under rapidly alternating high and low light intensities.Assimilation rates vary according to the frequency of the intermittentlight regime and it falls under two categories: (1) at 0.1 and0.2 Hz, the assimilation rate is equal to the average of therates observed at high and low light intensities under steadylight, and (2) under 1.0, 1.6 and 10 Hz the assimilation rateis equal to the rate observed under a mean steady irradiance.Moreover, the range of assimilation rates at a given frequencydepends on the difference between the high and the low intensities.Batch cultures of Oocystis sp. have been grown under intermittentlight of 0.1, 1.0 and 10.0 Hz (same mean intensity). Growthrate under intermittent light of 0.1 Hz is –40% lowerthan the control under steady light. Photosynthetic potential(P^B_max)and efficiency () change with the growth stages of thecultures. At the end of the logarithmic growth phase, both photosyntheticparameters are maximum at 1.0 Hz and minimum at 0.1 Hz. Averagecell concentrations of chlorophyll a increase as the frequencyof the light regime decreases. During the log phase, concentrationof carotenoids relative to chlorophyll a increases at 1.0 Hz,decreases at 0.1 Hz, and remains constant at 10.0 Hz. Underclear sky conditions, wave-induced light fluctuations in thephotic layer may therefore enhance primary production, especially(1) in the lower part of the photic layer, where low frequencylight changes might cause cell chlorophyll a to increase, and(2) at a depth of 1–4 m, where the main frequencies (ofthe order of 1.0 Hz), might cause a significant increase ofboth the photosynthetic potential (P^B_max)and efficiency (). ¹Contribution au programme du GIROQ (Groupe interuniversitairede recherches océanographiques du Québec) ²Adresse actuelle: Centre de recherches en nutrition, UniversitéLaval, Québec, Qué. G1K 7P4, Canada     

Temperature-dependent development of parthenogenetic embryos in Daphnia pulex de Geer

An in vitro study of the embryonic stages of Daphnia pulex deGeer was carried out by way of removing and isolating eggs fromthe females. The temperature-dependent development rates andthe developmental features were recorded photographically. Thetotal development time was 351 h at 5°C, 161 h at 10°Cand 87 h at 15°C. The relative times of development of embryonic‘stages’ also showed significant variation betweentemperatures. The observed variations in relative developmenttime of D.pulex embryos at different temperatures will questionthe accuracy of previously used methods for estimations of populationbirth rates using egg age determinations. ¹Present address: Akvaforsk, N-6600 Sunndalsøra, Norway ²Present address: Raadgivende Biologer as., Ladegaardsgaten9, 5035 Sandviken, Norway     

Hydrography and phytoplankton of the Ria de Vigo before and during a red tide of Gymnodinium catenatum Graham

At the end of summer 1986, hydrographic data and phytoplanktonsamples were collected on three occasions in the Ríade Vigo. The phytoplankton composition was studied in relationto the hydrography using principal component analysis and canonicalcorrelation analysis. Upwelling and the response of the planktoncommunity emerge as the main source of variation in the analysesWithin this framework, nutrient regeneration was observed, partlyattributable to ciliates and small flagellates. The second sourceof variation of the phytoplankton was the presence in the latersamples of a Gymnodinium catenatum red tide. Two other phytoplanktonpopulations were clearly differentiated One oceanic, dominatedby Erythropsis sp, Ceratium horridum and Stauroneis membranacea,which practically disappeared when the red Ode was established.The other, dominated by Solenicola setigera, dinoflagellatecysts and elongated diatoms, was a permanent population locatedbelow the populations which responded to upwelling. The penetrationof warm oceanic water into the ría during the secondday of observations altered the distributions of all the planktonicpopulations, isolating them in a downwelling zone. The energyof the oceanic intrusion could have been sufficient to removesediments from the interior of the ría and to stimulatethe formation of the red tide, by confining a water body inthe ría which lost little by mixing. It is likely thatthe resuspension of G.catenatum cysts provided the necessaryinoculum.     

The McCree-de Wit-Penning de Vries-Thornley Respiration Paradigms: 30 Years Later

To grow, an organism must respire substrates to produce C-skeletonintermediates, usable energy (i.e. ATP), and reducing power[i.e. NAD(P)H] to support biosynthesis and related processessuch as active transport of substrates. Respiration is alsoneeded—mainly as a supplier of ATP—to maintain existingbiomass in a functional state. As a result, quantifying linksbetween respiration, growth, and maintenance are needed to assesspotential plant productivity, to understand plant responsesto environmental factors, and as the basis of cost-benefit analysesof alternative uses of photosynthate. Beginning 30 years ago,and continuing for about 5 years, rapid advances were made inunderstanding and quantifying relationships between respirationand the processes it supports. Progress has continued sincethen, though often as refinements rather than novel advances.The simplest framework (i.e. paradigm) for relating respirationto other processes divides respiration into growth and maintenancefractions. This often involves a combination of empiricism andmechanism. A three-component framework (growth, maintenanceand wastage) has also been considered, although quantifyingwastage (theoretically or empirically) remains problematic.The more general and flexible framework, called the generalparadigm(GP, herein), relates respiration to any number of individualprocesses that it supports. The most important processes (fromC and energy balance perspectives) identified to date that requirerespiration are: biosynthesis of new structural biomass, translocationof photosynthate from sources to sinks, uptake of ions fromthe soil solution, assimilation of N (including N₂) and S intoorganic compounds, protein turnover, and cellular ion-gradientmaintenance. In addition, some part of respiration may be associatedwith wastage (e.g. futile cycles and mitochondrial electrontransport uncoupled from oxidative phosphorylation). Most importantly,the GP can (semi-)mechanistically relate respiration to underlyingphysiology and biochemistry. The GP is more complicated thanother approaches to describing or modelling respiration becauseit is more realistic, complete and mechanistic. This reviewdescribes a history of the GP and its present state. Futureresearch questions are suggested. Copyright 2000 Annals of BotanyCompany Review, growth, history, maintenance, model, paradigm, respiration     

Repartition des Appendiculaires au large des cotes de Californie

Twenty-seven taxa of appendicularians have been identified fromthe cruise CALCOFI n° 7202 and their distribution has beenstudied by various numerical methods, with the purpose of definingsimultaneously the groups of associated species and the groupsof stations possessing similar characteristics. Two large recurrentgroups have been defined by the method of Fager and McGowan,corresponding approximatively to the major water masses present:central Pacific waters and equatorial Pacific waters. The methodof Williams and Lambert permits the separation of 11 southernstations and a northern group divided into 2 subgroups dependingon the presence or absence of O. dioica. The rank correlationsgive results very similar to those obtained with point correlations.Finally, principal component analysis allow good separationof the northern and southern zones by the factorial plan 1–3,while representation of the stations by the factorial plan 2–3separates the two northern subgroups depending on the presenceor absence of O. dioica. The results obtained by the differentmethods are therefore very much alike, but it is difficult toconclude they are a result of the specific cruise, or whetherthey represent a general phenomenon.     

Pyrimidine Nucleotide Biosynthesis in Vinca rosea Cells: Changes in the Activity of the de novo and Salvage Pathways during Growth in a Suspension Culture

Marked changes in the activity of the ‘de novo’and ‘salvage’ pathways of pyrimidine biosynthesisduring growth of Vinca rosea cells in a batch suspension culturewere observed. The activity of these pathways was investigated by determiningthe contribution of ¹⁴C of [2-¹⁴Cluracil, 12-¹⁴Cluridine. and[6-¹⁴Clorotate to the cell constituents and by measuring theactivity of the several enzymes of these pathways. During the lag phase of the culture, ‘uracil-’ and‘uridine-salvage’ pathways made the predominantcontribution to nucleotide biosynthesis, but, following theinitiation of cell division, the ‘de novo’ pathwayfor nucleotide biosynthesis operated appreciably. These results suggest that nucleotide synthesis during cellgrowth in a suspension culture can be divided into two stages:a ‘turnover stage’, during the lag phase of cellgrowth, and a ‘true biosynthetic stage’, which isinitiated in the cell division phase.     

Influence du d?bit d'eau de mer dans un dispositif de culture ? fibres creuses dialysantes sur la croissance phytoplanctonique et 1'extraction des nitrates du milieu

It is demonstrated that the productive capacity of mass dialysisculture of phytoplankton is intimately related to the rate offlow of nutrient medium along the membrane. Comparison of culturesof Phaeodactylum tricornutum, subject to different medium flowrates (92 versus 250 ml.min^–1) during a 17-day growthperiod, reveals increased productivity (in terms of cell numbers,chlorophyll a, dry weight, cell nitrogen, cell carbon, ATP)at the higher flow rate. Differences are most pronounced inthe latter stages of growth (i.e., linear and stationary) attainingratios between 2 and 3 for cell nitrogen, cell carbon and ATP.Lower C/N ratios for the greater yielding culture translatesas enhanced osmotic diffusion as well as cellular assimilationof nitrates. The positive effects of increasing medium flowrate on phytoplankton growth result from improved dialyzer performancewith respect to low molecular weight solutes. This is evidencedin the proportionately greater values obtained for mass transferof nitrate-nitrogen. Accordingly, measures of nitrate clearanceindicate a progression from 29 to 85 ml.min^–1 in responseto augmenting sea water flow from 32 to 292 ml.min ^–1.The culture apparatus recently developed consists of a separatedialysis unit (a hollow-fiber cartridge used in hemodialysis)coupled to a temperature-controlled growth chamber. Culturesreceive a continuous flow of natural sea water and are grownin the batch dialysis mode. The main advantages of this methodrelate to its potential for large-scale, axenic algal culturebased on the abundant source of cheap nutrients that constitutesnatural sea water.