Caractérisation de la production particulaire par l’oursin Echinometra mathaei sur les récifs Indo-Pacifiques : influence des peuplements coralliens et implications sur la dynamique sédimentaire

The characteristics of the sedimentary grains produced by the sea urchin Echinometra mathaei were described from two reef sites: a fringing Acropora-dominated reef at La Reunion island (Indian Ocean) and a barrier Porites-dominated reef at Moorea island (French Polynesia). The composition of the sediment produced by Echinometra was determined from SEM observations. The size and shape of the particles were measured by using image analysis method. The grain diameters range between a few micrometres and 2 mm, with a large predominance (more than 80 %) of particles smaller than 400 μm. The grain size distribution is dependent on the nature of the grazed substratum. Echinometra individuals collected at La Reunion on branching Acropora colonies produce a higher proportion of particles smaller than 200 μm compared to those collected at Moorea on massive Porites colonies. At Moorea, more grains having a diameter comprised between 200 and 500 μm are produced. The microstructure of coral substrata affects the mean particle diameter, which is 192,17 μm for a Acropora substratum and 244,69 μm for a Porites substratum. Since the sediment derived from Acropora erosion is finer, the proportion of suspended material that is exported from the reef is greater at La Reunion than at Moorea. We estimate that, for similar erosion rates and hydrodynamic conditions, the production of sands by Echinometra mathaei is higher and the retention of this erosional sediment more effective on reefs dominated by massive Porites than on Acropora-dominated reefs. This result is in accordance with the proportions of suspension-moving grains that have been previously measured on Moorea and La Reunion reefs. This study highlighted the effect of coral communities on the production of particles related to the bioerosion and on the sedimentary budget.     

Ultraviolet‐B‐driven pigmentation and genetic diversity of benthic macroinvertebrates from high‐altitude Andean streams

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Dissimilatory microbial sulfur and methane metabolism in the water column of a shallow meromictic lake

Lake Harutori is a brackish meromictic lake with a steep physicochemical gradient in shallow water. Anoxic water below the chemocline has been characterized by high concentrations of sulfide (>10 mM) and methane (>1.5 mM). Previously, we reported that uncultured bacteria in the SEEP-SRB1 group were major sulfate reducers in the lake [21], but knowledge of sulfur oxidation and methane metabolism was scarce. In this current study, the Lake Harutori microbial community structure in the mixolimnion (at depths of 1.5 m and 3.0 m), upper chemocline (3.5 m), and monimolimnion (4.5 m) was further investigated by 16S rRNA gene amplicon sequencing and catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH). Reads of type I and II methanotrophs were retrieved mainly from 3.5 m and above. Methanotrophic bacteria detected by CARD-FISH accounted for 3.1% of DAPI-stained cells at 3.5 m. Detection frequencies of reads affiliated with the genera Sulfurimonas and Thiomicrorhabdus, which are known to comprise sulfur oxidizers, were relatively high at 3.5 m. Methanogenic archaeal reads were retrieved from the monimolimnion and they affiliated with the genus Methanosaeta. CARD-FISH counts indicated that the cells of Methanosaeta/Methanosarcina/Methanomicrobiales accounted for up to 0.8% of the DAPI-stained cells in the monimolimnion. On the other hand, many of the reads retrieved primarily from the monimolimnion were affiliated with phylogenetically novel uncultured groups.     

Black yeast habitat choices and species spectrum on high altitude creosote-treated railway ties

Polyextremotolerant black yeast-like fungi thrive in moderately hostile environments where they are concomitantly subjected to several types of stress, such as toxicity, scarce nutrient availability, and high or low temperature extremes. Their ability to assimilate alkylbenzenes (toxic environmental pollutants) enhances their growth in harsh conditions, including on railway ties. Samples were collected using cotton swabs, premoistened with physiological saline, from 658 oak and concrete railway ties at six train stations in Turkey at altitudes ranging between 1026 and 1427 m. The samples were inoculated on malt extract agar supplemented with chloramphenicol, and incubated at 26 °C for 4 weeks. Twenty-four samples (3.6 %), 17 from oak and 7 from concrete (5.6 % vs. 2 %; P = 0.02), tested positive for fungi. Exophiala crusticola was found to be the most common species (n = 13), followed by Exophiala phaeomuriformis (n = 7) and Exophiala heteromorpha (n = 4). These results suggest that hydrocarbons, particularly creosote-treated oak woods, support the growth of black yeasts, some of which are opportunists in humans.     

In situ study of relative electron transport rates in the marine macroalga <Emphasis Type="Italic">Fucus vesiculosus</Emphasis> in the Baltic Sea at different depths and times of year

The brown alga Fucus vesiculous is one of the few marine species in the Baltic Sea. Fucus vesiculosus shows high morphological and physiological variability as a response to its environmental conditions. The salinity in the Baltic Sea is 4–5 psu, compared to 35 psu in the Atlantic. Photosynthesis of algae is usually measured after collection and transportation to constant culture conditions. However, in this study, relative photosynthetic electron transport rates, calculated from chlorophyll a fluorescence parameters were compared in algae collected from 1 and 4 m depths by SCUBA divers. Measurements of light response curves from the same individuals of F. vesiculosus at different depths and times of the year have, to our knowledge, not been made previously. Measurements were performed on four different occasions during the spring of 2005 (25 February, 3 and 29 April, and 26 May) in the Baltic Sea, using rapid light curves generated with a Diving PAM. In addition, samples were collected for photoinhibition studies in the laboratory. The light response curves obtained in situ at 1 and 4 m depths for F. vesiculosus showed lower values of light saturation with depth. When algae from 1 and 4 m depths were exposed to high irradiances of photosynthetically active radiation (1,400 μmol photons m⁻² s⁻¹), algae from 1 m depth showed a higher degree of photoinhibition in comparison to algae from 4 m depth.     

Cord blood nesfatin-1 in large for gestational age pregnancies

ObjectiveTo investigate possible alterations in cord blood levels of adipokine nesfatin-1 (secreted by adipose tissue and pancreatic β-cells and implicated in glucose metabolism and insulin resistance), as well as insulin, in large (LGA) and appropriate for gestational age (AGA) pregnancies, granted that these groups differ in body fat mass and metabolic/endocrine mechanisms.Materials and methodsCord blood nesfatin-1 and insulin concentrations were prospectively measured in 40 LGA (9 born from diabetic and 31 from non-diabetic mothers) and 20 AGA singleton full-term infants as well as their mothers.ResultsCord blood nesfatin-1 concentrations were significantly lower in LGA compared to AGA neonates (b = ?0.206, SE 0.07, p = 0.005). However, cord blood nesfatin-1 concentrations were elevated in infants born from mothers with gestational diabetes mellitus (GDM), compared to those born from non-diabetic mothers, after controlling for group (b = 0.190, SE 0.10, p = 0.05). Finally, cord blood nesfatin-1 concentrations were lower in cases of vaginal delivery (b = 0.11, SE 0.05, p = 0.042). Insulin levels were significantly elevated, as customized centiles increased (b = 0.004, SE = 0.002, p = 0.016). No significant correlation was found between insulin and nesfatin-1 in maternal and umbilical cord levels.ConclusionsIn this study nesfatin-1 levels are decreased in LGA compared to AGA fetuses. Fetal nesfatin-1 concentrations are higher in cases of GDM and cord blood nesfatin-1 concentrations are lower in cases of vaginal delivery.     

Nouvelles recherches dans le bassin Plio-Pléistocène d’Anagni (Latium méridional, Italie)

The Anagni intra-apennine basin is especially rich in palaeontological and archaeological sites, spanning between middle Villafranchian and upper Pleistocene. The Italian Institute of Human Palaeontology has carried out researches in this region in the last 30 years. At Costa San Giacomo, middle Villafranchian yellow sands contain Mastodon arvernensis and Elephas meridionalis. At Colle Marino, a travertine layer and lime-clay contains mode 1 lithic industry, below any volcanic layers whose lower limit is 700 Ky old. Excavations have been restarted at Fontana Ranuccio, a 458 Ky Acheulian site with rich mammalian fauna (Elephas antiquus, Ursus deningeri, Bos primigenius, Dama clactoniana, Equus mosbachensis), a remarkable bone industry and four human teeth. Drillings, for about 40 m, have identified Matuyama-Brunhes limit 23 m under the main volcanic pyroclastite, in a thick limnic clay layer.     

Spatiotemporal patterns of neurogenesis in the appendicularian Oikopleura dioica

Incorporation of the thymidine analog bromodeoxyuridine (BrdU) was used to assess cytogenesis in the central nervous system (CNS) of the appendicularian Oikopleura dioica. A series of timed cumulative labelings carried out from 45 minutes (min) to 8 hours (h) after fertilization provided labeling patterns that showed when neurons and support cells residing at specific sites within the 9 h CNS became postmitotic. Throughout the CNS, which includes the cerebral ganglion, caudal ganglion and caudal nerve cord, neurogenesis occurs during an earlier time window than the genesis of support cells. Neurons are first generated at about 45 min to 1 h after fertilization in all 3 CNS regions, starting in the cerebral ganglion. Support cells are generated starting at about 2 h after fertilization. In both the cerebral ganglion and the caudal ganglion, neurons born during different time epochs settle in a specific spatial pattern, following a caudal to rostral gradient in the caudal ganglion and a more complex pattern in the cerebral ganglion. No such regional pattern was seen in the caudal nerve cord, where neurons born during different epochs were evenly distributed along the length of the cord. In the cerebral ganglion a small subpopulation of cells continued to incorporate BrdU from 8 h to at least 15 h and may represent a reserve of stem cells or progenitor cells that generate additional cells seen in the adult. The results show that this simple urochordate exhibits several vertebrate features of CNS cytogenesis, including a different timing of neurogenesis and gliogenesis (support cells being the likely candidates for glial cells in Oikopleura), gradients of neuron position according to birthdate, and a maintenance of neural cell precursors beyond embryonic and larval stages.     

Enhanced ultraviolet radiation can terminate sexual reproduction in the broadcasting coral species Acropora cervicornis Lamarck

The effects of enhanced ultraviolet radiation (280-400 nm: UVR) on the fecundity of Acropora cervicornis were measured in field-transplanted colonies from 20 m to 1 m depth and vice versa at La Parguera, Puerto Rico. Fecundity was estimated from histological sections made from tissue samples obtained at different time intervals during the experimental period (March - August 2003). All colonies transplanted from 20 m to 1 m showed a 100% reduction in gonads per mesentery per polyp one month after transplantation, while those transplanted from 1 m to 20 m did not show any significant reduction in fecundity throughout the experimental period. The latter colonies did show however, a delay in the spawning times by releasing their gamete bundles approximately two-three weeks after the controls at 1 m and two months after the controls at 20 m suggesting an induced response as a consequence of changes in their daily light cycle due to less radiation (PAR and UVR) available at 20 m compared to 1 m. Control colonies at 20 m spawned after the full moon of June 2003, while the controls at 1 m spawned 5-6 days after the full moon of July 2003. While a possible reabsorption of the gametes occurred in A. cervicornis colonies transplanted from 20 m to 1 m, the expulsion of these gametes due to the sudden stress caused by the transplantation is not discarded. The results suggest that sudden increases in UVR can completely stop sexual reproduction in ramose broadcasting coral species, which in turn can affect the dominance of the species and the composition and structure of shallow reef environments.     

Aggregata polibraxiona n. sp. (Apicomplexa: Aggregatidae) from Octopus bimaculatus Verrill, 1883 (Mollusca: Cephalopoda) from the Gulf of California,Mexico

The Apicomplexa Aggregata spp. are intracellular parasites of cephalopods that infect the intestinal tract of commercially important species such as Octopus bimaculatus, which sustains the octopus fishery in Baja California (B.C.), Mexico. In this study, Aggregata polibraxiona n. sp. was described from the cecum of O. bimaculatus collected from Bahia de Los Angeles, B. C. Light and electron microscopy revealed that oocysts and sporocysts were spherical to ovoid in shape. Sporulated oocysts (293–835 × 177–688 μm) contained 135–674 sporocysts (12–24 × 11–22 μm). The sporocyst wall was covered by tubular projections (0.55–2.19 μm in length) bifurcated in the top, unevenly distributed, covered by a thin membrane. Each sporocyst contains 11–13 sporozoites (16–26 × 1.20–3 μm). Three partial sequences of the 18S rDNA gene were obtained, and two phylogenetic approaches were performed according to Bayesian inference and Maximum Likelihood. In both phylogenetic reconstructions, the sequences of A. polibraxiona n. sp. were recovered as a monophyletic group within the genus Aggregata and placed as a sister group to Aggregata octopiana Lineage II. Aggregata polibraxiona n. sp. is the first Apicomplexa described from a cephalopod host from Mexico and extends the geographical range of Apicomplexa infecting cephalopods.     

Les foraminifères du Paléocène et de l'Éocène basal du sillon nord-pyrénéen (Aquitaine, France)

This paper presents for the first time the inventory of the Paleocene and Lower Eocene foraminifers located in the North Pyrenean trough, between the Atlantic Ocean and the neighbourhood of the town Pau. They have been studied from three outcrops. The Bidart Beach section shows the Lasseube Formation from the Cretaceous/Paleogene boundary to the base of the P 3a zone. The Loubieng Quarry section, near Orthez, represents the upper P 3a zone and the lower P 3b zone as well as the Lasseube Formation / Pont Labau Formation boundary. The interval between the upper part of the P 3b zone and the upperest part of the P 5 zone crops out along the Gan - Rébénacq road with a hiatus located at the Paleocene / Eocene boundary, the whole interval belonging to the Pont Labau Formation. 394 taxons of foraminifers are present in this formations: 349 benthic and 45 planktonic species. The Velasco type benthic foraminifers show a middle bathyal depositional environment, with a paleobathymetry included between 500-600 m and 1000 m: Nuttallides truempyi, Osangularia velascoensis, Bulimina trinitatensis. The Midway type species which were transported by the turbidite currents from the lower to middle neritic environments are frequent as well as the Cretaceous reworked species. The species number is low: 29 in the iridium layer of the Cretaceous/Paleogene boundary (P 0 zone). Fauna grows rich quickly in the Pα zone reaching 129 species. The diversity grows up progressively from P α to the P 4a zone (NP 8). The disappearances are rare until his horizon, but their number is bigger than the number of appearances from the P 4b zone. It reaches their maximum between the P 4c zone and the P 5 zone. It shows that the decline of the Paleocene fauna begins around 2 million years before the thermal event of the Paleocene / Eocene boundary in the Aquitaine sections. The disappearances stay important in the Lower Eocene - Ypresian, but the appearance of lots of Eocene species show that the fauna renewal is located in this stage. The Cretaceous taxa dominate in the Paleocene benthonic fauna. The appearance or the disappearance of some species has a stratigraphic value in the Aquitaine region: the disappearance of Coryphostoma incrassata in the P 1b zone, the appearances of Plectina dalmatina, Elongobula grata (P α); Bulimina tuxpamensis (P 2); Tritaxilina cubensis, Thalmannita madrugaensis (P 3a); Svenia bulbosa (P 3b); Discorbis perovalis (P 4a/NP 7); Elongobula pulchra, E. pupa, Asterigerina bartoniana, Neorotalia gr. tuberculata (P 4a/NP 8); Bigenerina pannonica, Pentellina pseudosaxorum (P 5/NP 9-10).     

Evaluation of low impact pressure waves as a quantitative sampling method for small fish in shallow water

Low impact pressure waves (LIMP) generated by small (< 1 g) underwater ignition capsules have been used to qualitatively and semi-quantitatively, as catch per unit effort, sample young-of-the-year (YOY) and juvenile fish in shallow (0-3 m) waters. In order to evaluate this method on small fish, four categories, 0+ and 1+ year Eurasian perch, 1+ year roach and 0+ to 1+ year pike, were subjected to the LIMP at distances of 0.5-5 m from the detonation point. At a distance < 1 m all specimens were stunned and either floated to the surface or sank to the bottom, whereas almost all were unaffected at distances > 3 m. The efficiency radius of the LIMP varied between 1.5 and 3.0 m, and the effective area was 7-28 m² depending on habitat and species. The average effective area for the two extensively studied categories (0+ perch and 1+ roach) was 17.9 m². Both depth and vegetation affected the effective area. The smallest area was obtained at < 1 m depth with vegetation present, and the largest at 1-2 m depths with no vegetation present. Within each fish category, the method sampled fish independently of length suggesting that a size/year-class is sampled equally. The proportion of affected fish that sank was large and species-dependent. In addition to the netting of surfaced fish, collecting fish from the bottom is recommended for achieving an accurate quantitative estimate. The tested parameters of the LIMP, P_max and Impulse, declined as a function of distance following a negative exponential growth model with a baseline. The similar-shaped responses among the fish categories suggest that the method works at depths < 3 m also in heterogeneous environments, and that the method can be used to quantitatively estimate abundance of small fish with swim bladders. A model for quantitative abundance estimates based on the evaluation is presented.     

In vivo and in vitro studies of MUC1 regulation in sheep endometrium

In this study, we investigated the expression of mucin 1 (MUC1) mRNA and protein in sheep endometrium at different time points during follicular and luteal phases of estrous cycle, and also determined the effect of steroid hormone treatments and interferon tau (IFNτ) on MUC1 mRNA expression in endometrial cell culture in vitro. In experiment one, 15 Welsh mountain ewes were synchronized to a common estrus and killed at precise stages of estrous cycle corresponding to (1) pre-LH peak, (2) LH peak, (3) post-LH peak, (4) early luteal, and (5) mid-luteal. Reproductive tracts were harvested and mRNA was extracted from the endometrial tissues. Parts of the uterine horns were fixed for immunohistochemistry. In experiment two, mixed populations of ovine endometrial cells (from slaughterhouse material collected at the postovulatory stage of the estrous cycle) were cultured to 70% confluence before treatment with (1) progesterone (P₄, 10 ng/mL, for 48 hours), (2) estradiol (E₂, 100 pg/mL, for 48 hours), or with (3) E₂ priming for 12 hours (100 pg/mL) followed by P₄ (10 ng/mL) for 36 hours. These were compared with: (4) IFNτ (10 ng/mL, for 48 hours), and (5) basic medium (Dulbecco Modified Eagle Medium /F12) as control. The results showed that MUC1 mRNA and protein expression in sheep endometrium were highest during the midluteal stage and very low during the post-LH period compared with the other stages (P < 0.05). MUC1 immunostaining in the luminal epithelium was apically restricted and was not significantly different across all stages of estrous cycle except at the post-LH peak where it was significantly low. In cell culture, MUC1 mRNA expression was significantly upregulated by both steroids either singly or in combination (P < 0.05), and downregulated in the presence of IFNτ. In conclusion, endometrial MUC1 expression is cyclically regulated by both E₂ and P₄ in vivo and in vitro, and directly downregulated by IFNτ treatment in vitro.     

Étude biostratigraphique et paléoenvironnementale des diatomées pyritisées de l'intervalle Paléocène supérieur-Éocène inférieur du sondage de Saint-Josse (France)

This paper presents the results of a biostratigraphic analysis of pyritized diatom assemblages in the Saint-Josse core (CC82) located in the northern part of the Paris basin (coordinates: X =555?000, Y =307?324 and Z =56.9 m). During the Paleocene-Eocene this locality was situated in a small bight of the North Sea Basin. The results are obtained from sediments of the Thanet and Mont-Bernon group equivalents belonging to the Paleocene-Eocene interval. Thirteen samples were studied and eleven contain pyritized diatoms. By epigenesis, the siliceous frustule of the diatom is changed into a pyritized skeleton with all the ornamentation very well preserved such as the velum, the areolae, the labiate processes, etc. Dispersive X-Ray analyses show this complete replacement of silica by pyrite. Another form of pyritization is crystallization of pyrite (in cubes, pyritohedrons, octahedrons, framboids) in internal cavities of the diatoms to produce internal moulds, also called steinkerns, which preserve the external morphology of the diatoms and some details such as the girdle. Despite pyritization, diatoms can often be recognized at the species level; brackish and marine species were observed but no fresh water specimens were encountered. Pyrite is easily altered into iron oxides. In outcrops, pyritized diatoms can be obscured or destroyed by oxidation. We have chosen borehole samples for this study to avoid the affects of weathering. Deposits from the Sorrus Unit (of the Thanet Group) have low abundances of pyritized diatoms (3 to 25 specimens per sample). This unit contains allochtonous diatom assemblages comprising Actinoptychussenarius, Coscinodiscus morsianus var. morsianus, and Coscinodiscus morsianus var. moelleri. Sample 34.31-34.45 from this unit is particularly interesting. It contains three specimens of Paralia siberica var. laevis, which is typical of an estuarine or littoral paleoenvironment, and corresponds to the more continental deposit of the Sorrus Unit. Seven samples, taken in the Argile de Saint-Aubin Unit (from the Mont-Bernon Group), contain more than 200 pyritized diatoms and between 9 to 16 different species per sample. A brackish assemblage (Actinoptychus senarius, Coscinodiscus commutatus and Stellarima microtrias) and a marine assemblage (C. morsianus var. morsianus, Coscinodiscus var. moelleri, Fenestrella antiqua, Odontellaheibergii, Rhizosolenia sp. 1 and Trinacria regina) are observed. The brackish assemblage expands in the upper part of the Saint-Aubin Unit indicating more widespread brackish paleoenvironmental conditions. Pyritized diatoms are important fossil markers in the Paris basin mainly when siliceous fossils (silicoflagellates or radiolarians) and others microfossils (foraminifers and dinoflagellates) are very poor or absent. Two diatom assemblages have been identified in the Saint-Josse borehole. The first assemblage D1, comprising C. morsianus var. moelleri (high occurrence), C. morsianus (a few) and T. regina (rare), is recorded in the Sorrus, La Calotterie, Bois Gorguette, Le Goulet and lower Saint-Aubin Units. The second assemblage D2, characterized by great abundance of F. antiqua and decreasing numbers of C. morsianus species, is found in the upper part of the Saint-Aubin Unit. These diatom assemblages can be correlated with other biozonations established in the North Sea basin and based on nannoplankton and diatoms (King, 1983), diatoms (Mitlehner, 1996) and calcareous nannoplankton (Martini, 1971). F. antiqua and C. morsianus var. moelleri are the more important diatom species encountered. F. antiqua (previously named Coscinodiscus sp. 1, King, 1983) is the fossil marker used by King to define his NSP4 biozone. The base of NSP4 corresponds to the lowest occurrence of F. antiqua and the top is marked by the highest occurrence of this species. The Sorrus, La Calotterie, Bois Gorguette, Le Goulet and Saint-Aubin (“Sparnacian” stage) Units, the last one comprising F. antiqua (increasing to acme), correspond to the NSP4 zone of King (1983). The Mont-Hulin and Château de la Bruyère Units correspond probably to the NSP5 zone of King (1983). F. antiqua and C. morsianus var. moelleri were also used by Mitlehner (1996) to differentiate the NSP4a zone (low abundance of F. antiqua and abundance of C. morsianus var. moelleri) from the NSP4b zone (great abundance and acme of F. antiqua). The abundance of C. morsianus var. moelleri is recorded in the lower part of Saint-Aubin Unit and the abundance of F. antiqua (high peak at 46% in the sample 17.87) is found in the upper part of Saint-Aubin Unit. Therefore, Sorrus, La Calotterie, Bois Gorguette, Le Goulet and the lower part of Saint-Aubin Units are correlated with the NSP4a zone and the upper part of Saint-Aubin Unit with the NSP4b zone. By correlating the calcareous nannoplankton biozonation (NP) of Martini (1971) with the biozonation of King (1983), adapted by Mitlehner (1996), the boundary between the NP9 and NP10 zones could be located in the 18.75-17.87 interval and the NP10-NP11 boundary at the top of Saint-Aubin Unit. Lithostratigraphic correlations between the units of the Saint-Josse borehole (Paris basin) and the formations of the North Sea basin can be established. The great abundance of C. morsianus var. moelleri and the great abundance (including acme) of F. antiqua are respectively recorded in the Sele and Balder Formations. Therefore, the interval Sorrus/lower Saint-Aubin Units is correlated with the Sele Formation and upper part of Saint-Aubin Unit with the Balder Formation.     

Analysis of functional consequences of haplogroup J polymorphisms m.4216T > C and m.3866T > C in human MT-ND1: Mutagenesis of homologous positions in Escherichia coli

MtDNA sequence variation is presumed to be neutral in effect, but associations with diseases and mtDNA haplogroups have been reported. The aim here was to evaluate the functional consequences of m.4216T > C present in haplogroup J. Furthermore, we evaluated m.3866T > C in MT-ND1, a variant detected in a child belonging to haplogroup J and with an isolated complex I deficiency. Homologous substitutions were introduced into Escherichia coli. NADH dehydrogenase domain activity of NDH-1 with either one or both mutations was markedly decreased suggesting that m.4216T > C and m.3866T > C may have an effect on the structural integrity of complex I.     

Linkages between surface and deep circulations in the southern Japan Sea during the last 27,000 years: Evidence from planktic foraminiferal assemblages and stable isotope records

We analyzed planktic foraminiferal assemblages, oxygen and carbon isotope records, and the presence or absence of laminations to reconstruct the paleoenvironments of the southern Japan Sea since the last glacial period. Data were collected from two well-dated cores. One core (water depth 999 m) included thinly laminated mud layers, the other (water depth 283 m) contained nonlaminated sediments. Tephrochronology and accelerator mass spectrometry ¹⁴C dating of 14 horizons revealed that the two cores contained continuous records of the last 27 cal kyr. A total of 13 planktic foraminiferal species belonging to six genera were identified in down-core samples. The typical indicators of the Tsushima Current water, Globigerinoides ruber, Neogloboquadrina dutertrei, Pulleniatina obliquiloculata, Globigerinoides tenellus, and Globigerinita glutinata occurred since 9.3 cal kyr BP. Neogloboquadrina incompta, which was the dominant species in the Tsushima Current region of the modern Japan Sea, first occurred at 8.2 cal kyr BP and dominated the assemblage since 7.3 cal kyr BP. These results clearly indicate that the warm Tsushima Current started to inflow into the Japan Sea at 9.3 cal kyr BP, and the modern surface conditions in the southern Japan Sea were essentially established at 7.3 cal kyr BP. Our data and comparison of the presence or absence of laminated sediments in three locations from the southern Japan Sea suggest that deep circulation during the deglacial period was weaker than that at present. In addition, deep circulation in the modern Japan Sea, which supplies oxygen-rich water to the entire basin, started probably in association with the first inflow of the Tsushima Current beginning at 9.3 cal kyr BP.     

The sensory arrays of the ant,Temnothorax rugatulus

Individual differences in response thresholds to task-related stimuli may be one mechanism driving task allocation among social insect workers. These differences may arise at various stages in the nervous system. We investigate variability in the peripheral nervous system as a simple mechanism that can introduce inter-individual differences in sensory information. In this study we describe size-dependent variation of the compound eyes and the antennae in the ant Temnothorax rugatulus. Head width in T. rugatulus varies between 0.4 and 0.7 mm (2.6–3.8 mm body length). But despite this limited range of worker sizes we find sensory array variability. We find that the number of ommatidia and of some, but not all, antennal sensilla types vary with head width.The antennal array of T. rugatulus displays the full complement of sensillum types observed in other species of ants, although at much lower quantities than other, larger, studied species. In addition, we describe what we believe to be a new type of sensillum in hymenoptera that occurs on the antennae and on all body segments. T. rugatulus has apposition compound eyes with 45–76 facets per eye, depending on head width, with average lens diameters of 16.5 μm, rhabdom diameters of 5.7 μm and inter-ommatidial angles of 16.8°. The optical system of T. rugatulus ommatidia is severely under focussed, but the absolute sensitivity of the eyes is unusually high.We discuss the functional significance of these findings and the extent to which the variability of sensory arrays may correlate with task allocation.     

Hypoxia tolerance in the copepod Calanoides carinatus and the effect of an intermediate oxygen minimum layer on copepod vertical distribution in the northern Benguela Current upwelling system and the Angola-Benguela Front

There is a growing concern that hypoxic and anoxic areas in the sea spread in extent and intensity, posing a severe risk to marine ecosystems and fisheries. Hypoxia may affect fish stocks directly or via detrimental effects on important prey species, such as zooplankton. A unique feature of the northern Benguela Current upwelling region and Angola-Benguela frontal system is a pronounced intermediate oxygen minimum layer (IOML) at 60-500 m depth with oxygen concentrations ≤ 1.4 mg O₂l^− 1 (minimum < 0.7 mg O₂l^− 1). Field studies during February-March 2002 demonstrated that the abundance of calanoid copepods and the biomass of mesozooplankton in general were severely reduced within the IOML. The dominant copepod Calanoides carinatus showed a bimodal vertical distribution with parts of the population either comprising all developmental stages concentrated in the surface layer (0-60 m), or copepodids C5 diapausing below 400 m depth apparently avoiding the IOML. Accordingly, abundances of other calanoid copepods were higher at the surface and below 300 m than in the centre of the IOML. The scarcity of planktonic life within the IOML raises the question whether this layer represents an effective barrier for zooplankton vertical migrations. Especially in C. carinatus, ontogenetic vertical migration plays a key role in the retention of the population within the productive upwelling region and for the rapid re-colonisation of plumes of newly upwelled water. To address this issue, the hypoxia tolerance of C. carinatus was determined in a series of laboratory-based, closed-bottle experiments in January 2005. Copepods were kept in gas-tight bottles and the decreasing oxygen concentrations were monitored to establish their minimum oxygen demands. Although copepodids survived apparently unharmed at surprisingly low oxygen concentrations of ca. 1.5 mg O₂l^− 1, they could not tolerate oxygen levels < 1.1 mg O₂l^− 1, implying that the core of the IOML, where O₂ concentrations are below this threshold, is uninhabitable for C. carinatus. In contrast, the IOML may represent a refuge from competition and predation for other copepod species specifically adapted to hypoxic environments.     

Ethnic diversity and cord blood banking: satisfying the unmet need

Background aimsIn this study, the authors sought to assess whether cord blood units (CBUs) collected from donors of non-European ethnic backgrounds are utilized for umbilical cord blood transplantation (UCBT) at a different rate than those of European ethnic backgrounds. The authors also examined potential methods of enriching these under-represented ethnic backgrounds in cord blood bank (CBB) inventories without increasing financial overheads and without compromising total inventory utilization or post-transplant outcomes.MethodsData from N = 6506 searchable or shipped Anthony Nolan Cell Therapy Centre grafts were used in this study. Banked grafts were graded from A+ to D based on total nucleated cell and CD34+ cell content. Utilizations of each grade group were further stratified by graft ethnic background. The Mantel–Cox log-rank test was performed in conjunction with Kaplan–Meier survival analysis to compare utilization rates and post-transplant outcomes. For shipped grafts, levels of HLA matching at HLA-A, HLA-B and HLA-DR loci were also analyzed by graft ethnic background and grade using data from the Eurocord/EBMT registry.ResultsOverall utilization of non-European grafts did not significantly differ from that of European grafts (2.5% versus 2.2%, P = 0.23). However, significant differences were found when stratifying utilization rates by cell content. The probability of non-European D grade grafts being utilized was 3-fold higher than that of European D grade grafts (1.1% versus 0.4%, P = 0.03) and comparable to that of European C grade grafts (1.1% versus 0.9%, P = 0.90). No significant differences were found between D and C grade grafts in terms of overall survival (OS) (P = 0.12), in part due to a disproportionate utilization of D grade grafts for pediatric UCBT (74% versus 39%, age difference P < 0.001). Furthermore, non-European graft shipments were 4-fold less likely to be a 6/6 HLA match to their recipients relative to European graft shipments (7% versus 29%).ConclusionsThe authors have identified a niche for CBUs of low cell content collected from donors of non-European ethnic backgrounds that has been overlooked by previous studies. Banking of these CBUs for pediatric UCBT instead of CBUs from European donors containing modestly higher cell content is an ethical approach to increasing the ethnic diversity of CBB inventory—and, consequently, the probability of non-European recipients finding a 6/6 HLA-matched graft—without compromising post-transplant OS or overall rate of inventory utilization.