Proceedings of the international colloquium photosynthesis and remote sensing

The in vivo specific absorption coefficient of phytoplankton a*ph (lambda) was measured along an equatorial transect in the Pacific Ocean during the JGOFS-cruise in Octobre 1994 in order to validate bio-optical models of primary production. The fiber filter technique was used on board, as well as spectrofluorometry for pigment determination and flow cytometry for cells counting. The a*ph (435-441 nm) walues strongly decreased from oligotrophic to mesotrophic waters (between 170°E and 153°W). This zonal variation reflected a change in phytoplankton composition, dominated by #Prochlorococcus$ in the oligotrophic zone and by picoeucaryotes in the mesotrophic one. Such variations in a*ph have to be taken into account for estimating primary production of the equatorial Pacific Ocean from ocean colour imagery. (Résumé d'auteur

An algorithm for detecting <i>Trichodesmium</i> surface blooms in the South Western Tropical Pacific

<i>Trichodesmium</i>, a major colonial cyanobacterial nitrogen fixer, forms large blooms in NO₃-depleted tropical oceans and enhances CO₂ sequestration by the ocean due to its ability to fix dissolved dinitrogen. Thus, its importance in C and N cycles requires better estimates of its distribution at basin to global scales. However, existing algorithms to detect them from satellite have not yet been successful in the South Western Tropical Pacific (SP). Here, a novel algorithm (TRICHOdesmium SATellite) based on radiance anomaly spectra (RAS) observed in SeaWiFS imagery, is used to detect <i>Trichodesmium</i> during the austral summertime in the SP (5° S–25° S 160° E–170° W). Selected pixels are characterized by a restricted range of parameters quantifying RAS spectra (e.g. slope, intercept, curvature). The fraction of valid (non-cloudy) pixels identified as <i>Trichodesmium</i> surface blooms in the region is low (between 0.01 and 0.2 %), but is about 100 times higher than deduced from previous algorithms. At daily scales in the SP, this fraction represents a total ocean surface area varying from 16 to 48 km² in Winter and from 200 to 1000 km² in Summer (and at monthly scale, from 500 to 1000 km² in Winter and from 3100 to 10 890 km² in Summer with a maximum of 26 432 km² in January 1999). The daily distribution of <i>Trichodesmium</i> surface accumulations in the SP detected by TRICHOSAT is presented for the period 1998–2010 which demonstrates that the number of selected pixels peaks in November–February each year, consistent with field observations. This approach was validated with in situ observations of <i>Trichodesmium</i> surface accumulations in the Melanesian archipelago around New Caledonia, Vanuatu and Fiji Islands for the same period

Probable hepatic capillariosis and hydatidosis in an adolescent from the late Roman period buried in Amiens (France)

Two calcified objects recovered from a 3rd to 4th-century grave of an adolescent in Amiens (Northern France) were identified as probable hydatid cysts. By using thin-section petrographic techniques, probable Calodium hepaticum (syn. Capillaria hepatica) eggs were identified in the wall of the cysts. Human hepatic capillariosis has not been reported from archaeological material so far, but could be expected given the poor level of environmental hygiene prevalent in this period. Identification of tissue-dwelling parasites such as C. hepaticum in archaeological remains is particularly dependent on preservation conditions and taphonomic changes and should be interpreted with caution due to morphological similarities with Trichuris sp. eggs

Rapport de la campagne PROPPAC 04 à bord du N.O. Le Suroît (30 octobre au 26 novembre 1989)

La campagne PROPPAC 4, dont l'ORSTOM était maître d'oeuvre, s'est déroulée du 30 octobre au 26 novembre 1989 entre 20°S (nord de la Nouvelle-Calédonie) et 5°S le long de 165°E. L'objectif était de décrire en deux points fixes de 8 jours la variabilité à court terme des paramètres hydrologiques et planctoniques, leur répartition le long de la colonne d'eau, la distribution des différentes classes d'organismes et de mesurer l'intensité des flux : advection et mélanges, taux de sédimentation, production primaire et secondaire. Ces informations, recueillies dans deux situations oligotrophes considérées comme typiques, doivent permettre de compléter les données rudimentaires de biologie qui sont collectées au cours des stations de courte durée des radiales bi-annuelles SURTROPAC depuis 1984 et servir à la définition de la relation production-hydrologie dans le Pacifique occidental. La première station de 8 jours, dont la position a été choisie à l'issue d'une radiale préliminaire, était située à 7-8°S et caractérisée par une pycnocline profonde (75 m) et marquée, avec un maximum de chlorophylle vers 80-100 m. La seconde, située à 16°S, correspondrait à une structure hydrologique avec un faible gradient et des sels nutritifs vers 140 m, le maximum de chlorophylle se situant à 120-140 m. (Résumé d'auteur

BEATRIX: The international breeder materials exchange

The BEATRIX experiment is an IEA-sponsored effort that involves the exchange of solid breeder materials and shared irradiation testing among research groups in several countries. The materials will be tested in both closed capsules (to evaluate material lifetime) and opened capsules (to evaluate purge-flow tritium recovery). Pre- and post-irradiation measurement of thermophysical and mechanical properties will also be carried out

Molecular diagnosis of Pseudoterranova decipiens s.s in human, France

Background: Anisakis and Pseudoterranova are the main genera involved in human infections caused by nematodes of the Anisakidae family. Species identification is complicated due to the lack of differential morphological characteristics at the larval stage, thus requiring molecular differentiation. Pseudoterranova larvae ingested through raw fish are spontaneously eliminated in most cases, but mechanical removal by means of endoscopy might be required. To date, only very few cases of Pseudoterranova infection have been reported in France. Case presentation: A 19-year-old woman from Northeastern France detected, while brushing her teeth, a larva exiting through her mouth. The patient who presented with headache, diarrhea, and abdominal cramps reported having eaten baked cod. The worm was a fourth-stage larva with a size of 22 × 0.9 mm, and molecular biology identified it as Pseudoterranova decipiens sensu stricto (s. s.). In a second P. decipiens infection case, occurring a few months later, a worm exited through the patient’s nose after she had eaten raw sea bream. Conclusion: These two cases demonstrate that Pseudoterranova infection is not uncommon among French patients. Therefore, molecular techniques should be more widely applied for a better characterization of anisakidosis epidemiology in France

α,β-D-Constrained Nucleic Acids Are Strong Terminators of Thermostable DNA Polymerases in Polymerase Chain Reaction

(SC5′, RP) α,β-D- Constrained Nucleic Acids (CNA) are dinucleotide building blocks that can feature either B-type torsional angle values or non-canonical values, depending on their 5′C and P absolute stereochemistry. These CNA are modified neither on the nucleobase nor on the sugar structure and therefore represent a new class of nucleotide with specific chemical and structural characteristics. They promote marked bending in a single stranded DNA so as to preorganize it into a loop-like structure, and they have been shown to induce rigidity within oligonucleotides. Following their synthesis, studies performed on CNA have only focused on the constraints that this family of nucleotides introduced into DNA. On the assumption that bending in a DNA template may produce a terminator structure, we investigated whether CNA could be used as a new strong terminator of polymerization in PCR. We therefore assessed the efficiency of CNA as a terminator in PCR, using triethylene glycol phosphate units as a control. Analyses were performed by denaturing gel electrophoresis and several PCR products were further analysed by sequencing. The results showed that the incorporation of only one CNA was always skipped by the polymerases tested. On the other hand, two CNA units always stopped proofreading polymerases, such as Pfu DNA polymerase, as expected for a strong replication terminator. Non-proofreading enzymes, e.g. Taq DNA polymerase, did not recognize this modification as a strong terminator although it was predominantly stopped by this structure. In conclusion, this first functional use of CNA units shows that these modified nucleotides can be used as novel polymerization terminators of proofreading polymerases. Furthermore, our results lead us to propose that CNA and their derivatives could be useful tools for investigating the behaviour of different classes of polymerases

Photoinduced HS state in the first spin-crossover chain containing a cyanocarbanion as bridging ligand

A new polymeric approach, based on cyanocarbanion ligands, for the design of spin crossover (SCO) compounds led us to the compound [Fe(abpt)2(tcpd)] (1) (tcpd^2 = (C[C(CN)2|3)^2 , abpt = 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole) which has been characterised as the first SCO molecular chain involving a cyanocarbanion as bridging ligand.Gomez Garcia, Carlos Jose, [email protected]

An algorithm for detecting Trichodesmium surface blooms in the South Western Tropical Pacific

Trichodesmium, a major colonial cyanobacterial nitrogen fixer, forms large blooms in NO₃-depleted tropical oceans and enhances CO₂ sequestration by the ocean due to its ability to fix dissolved dinitrogen. Thus, its importance in C and N cycles requires better estimates of its distribution at basin to global scales. However, existing algorithms to detect them from satellite have not yet been successful in the South Western Tropical Pacific (SP). Here, a novel algorithm (TRICHOdesmium SATellite) based on radiance anomaly spectra (RAS) observed in SeaWiFS imagery, is used to detect Trichodesmium during the austral summertime in the SP (5° S–25° S 160° E–170° W). Selected pixels are characterized by a restricted range of parameters quantifying RAS spectra (e.g. slope, intercept, curvature). The fraction of valid (non-cloudy) pixels identified as Trichodesmium surface blooms in the region is low (between 0.01 and 0.2 %), but is about 100 times higher than deduced from previous algorithms. At daily scales in the SP, this fraction represents a total ocean surface area varying from 16 to 48 km² in Winter and from 200 to 1000 km² in Summer (and at monthly scale, from 500 to 1000 km² in Winter and from 3100 to 10 890 km² in Summer with a maximum of 26 432 km² in January 1999). The daily distribution of Trichodesmium surface accumulations in the SP detected by TRICHOSAT is presented for the period 1998–2010 which demonstrates that the number of selected pixels peaks in November–February each year, consistent with field observations. This approach was validated with in situ observations of Trichodesmium surface accumulations in the Melanesian archipelago around New Caledonia, Vanuatu and Fiji Islands for the same period