Adaptation Strategies to High Hydrostatic Pressures in Pseudothermotoga species Revealed by Transcriptional Analyses

Pseudothermotoga elfii strain DSM9442 and P. elfii subsp. lettingae strain DSM14385 are hyperthermophilic bacteria. P. elfii DSM9442 is a piezophile and was isolated from a depth of over 1600 m in an oil-producing well in Africa. P. elfii subsp. lettingae is piezotolerant and was isolated from a thermophilic bioreactor fed with methanol as the sole carbon and energy source. In this study, we analyzed both strains at the genomic and transcriptomic levels, paying particular attention to changes in response to pressure increases. Transcriptomic analyses revealed common traits of adaptation to increasing hydrostatic pressure in both strains, namely, variations in transport membrane or carbohydrate metabolism, as well as species-specific adaptations such as variations in amino acid metabolism and transport for the deep P. elfii DSM9442 strain. Notably, this work highlights the central role played by the amino acid aspartate as a key intermediate of the pressure adaptation mechanisms in the deep strain P. elfii DSM9442. Our comparative genomic and transcriptomic analysis revealed a gene cluster involved in lipid metabolism that is specific to the deep strain and that was differentially expressed at high hydrostatic pressures and might, thus, be a good candidate for a piezophilic gene marker in Pseudothermotogales.

Sinking Trichodesmium fixes nitrogen in the dark ocean

The photosynthetic cyanobacterium Trichodesmium is widely distributed in the surface low latitude ocean where it contributes significantly to N2 fixation and primary productivity. Previous studies found nifH genes and intact Trichodesmium colonies in the sunlight-deprived meso- and bathypelagic layers of the ocean (200-4000 m depth). Yet, the ability of Trichodesmium to fix N2 in the dark ocean has not been explored. We performed 15N2 incubations in sediment traps at 170, 270 and 1000 m at two locations in the South Pacific. Sinking Trichodesmium colonies fixed N2 at similar rates than previously observed in the surface ocean (36-214 fmol N cell-1 d-1). This activity accounted for 40 ± 28% of the bulk N2 fixation rates measured in the traps, indicating that other diazotrophs were also active in the mesopelagic zone. Accordingly, cDNA nifH amplicon sequencing revealed that while Trichodesmium accounted for most of the expressed nifH genes in the traps, other diazotrophs such as Chlorobium and Deltaproteobacteria were also active. Laboratory experiments simulating mesopelagic conditions confirmed that increasing hydrostatic pressure and decreasing temperature reduced but did not completely inhibit N2 fixation in Trichodesmium. Finally, using a cell metabolism model we predict that Trichodesmium uses photosynthesis-derived stored carbon to sustain N2 fixation while sinking into the mesopelagic. We conclude that sinking Trichodesmium provides ammonium, dissolved organic matter and biomass to mesopelagic prokaryotes.

Hydrothermal plumes as hotspots for deep-ocean heterotrophic microbial biomass production

Carbon budgets of hydrothermal plumes result from the balance between carbon sinks through plume chemoautotrophic processes and carbon release via microbial respiration. However, the lack of comprehensive analysis of the metabolic processes and biomass production rates hinders an accurate estimate of their contribution to the deep ocean carbon cycle. Here, we use a biogeochemical model to estimate the autotrophic and heterotrophic production rates of microbial communities in hydrothermal plumes and validate it with in situ data. We show how substrate limitation might prevent net chemolithoautotrophic production in hydrothermal plumes. Elevated prokaryotic heterotrophic production rates (up to 0.9 gCm^-2y^-1) compared to the surrounding seawater could lead to 0.05 GtCy^-1 of C-biomass produced through chemoorganotrophy within hydrothermal plumes, similar to the Particulate Organic Carbon (POC) export fluxes reported in the deep ocean. We conclude that hydrothermal plumes must be accounted for as significant deep sources of POC in ocean carbon budgets.

On this side of the fence: Functional responses to linear landscape features shape the home range of large herbivores

Understanding the consequences of global change for animal movement is a major issue for conservation and management. In particular, habitat fragmentation generates increased densities of linear landscape features that can impede movements. While the influence of these features on animal movements has been intensively investigated, they may also play a key role at broader spatial scales (e.g. the home range scale) as resources, cover from predators/humans, corridors/barriers, or landmarks. How space use respond to varying densities of linear features has been mostly overlooked in large herbivores, in contrast to studies done on predators. Focusing on large herbivores should provide additional insights to understand how animals solve the trade-off between energy acquisition and mortality risk. Here, we investigated the role of anthropogenic (roads and tracks) and natural (ridges, valley bottoms and forest edges) linear features on home range features in five large herbivores. We analysed an extensive GPS monitoring data base of 710 individuals across nine populations, ranging from mountain areas mostly divided by natural features to lowlands that were highly fragmented by anthropogenic features. Nearly all of the linear features studied were found at the home range periphery, suggesting that large herbivores primarily use them as landmarks to delimit their home range. In contrast, for mountain species, ridges often occurred in the core range, probably related to their functional role in terms of resources and refuge. When the density of linear features was high, they no longer occurred predominantly at the home range periphery, but instead were found across much of the home range. We suggest that, in highly fragmented landscapes, large herbivores are constrained by the costs of memorising the spatial location of key features, and by the requirement for a minimum area to satisfy their vital needs. These patterns were mostly consistent in both males and females and across species, suggesting that linear features have a preponderant influence on how large herbivores perceive and use the landscape.

Mesopelagic microbial carbon production correlates with diversity across different marine particle fractions

The vertical flux of marine snow particles significantly reduces atmospheric carbon dioxide concentration. In the mesopelagic zone, a large proportion of the organic carbon carried by sinking particles dissipates thereby escaping long term sequestration. Particle associated prokaryotes are largely responsible for such organic carbon loss. However, links between this important ecosystem flux and ecological processes such as community development of prokaryotes on different particle fractions (sinking vs. non-sinking) are yet virtually unknown. This prevents accurate predictions of mesopelagic organic carbon loss in response to changing ocean dynamics. Using combined measurements of prokaryotic heterotrophic production rates and species richness in the North Atlantic, we reveal that carbon loss rates and associated microbial richness are drastically different with particle fractions. Our results demonstrate a strong negative correlation between prokaryotic carbon losses and species richness. Such a trend may be related to prokaryotes detaching from fast-sinking particles constantly enriching non-sinking associated communities in the mesopelagic zone. Existing global scale data suggest this negative correlation is a widespread feature of mesopelagic microbes.

Responses to the Hydrostatic Pressure of Surface and Subsurface Strains of Pseudothermotoga elfii Revealing the Piezophilic Nature of the Strain Originating From an Oil-Producing Well

Microorganisms living in deep-oil reservoirs face extreme conditions of elevated temperature and hydrostatic pressure. Within these microbial communities, members of the order Thermotogales are predominant. Among them, the genus Pseudothermotoga is widespread in oilfield-produced waters. The growth and cell phenotypes under hydrostatic pressures ranging from 0.1 to 50 MPa of two strains from the same species originating from subsurface, Pseudothermotoga elfii DSM9442 isolated from a deep African oil-producing well, and surface, P. elfii subsp. lettingae isolated from a thermophilic sulfate-reducing bioreactor, environments are reported for the first time. The data support evidence for the piezophilic nature of P. elfii DSM9442, with an optimal hydrostatic pressure for growth of 20 MPa and an upper limit of 40 MPa, and the piezotolerance of P. elfii subsp. lettingae with growth occurring up to 20 MPa only. Under the experimental conditions, both strains produce mostly acetate and propionate as volatile fatty acids with slight variations with respect to the hydrostatic pressure for P. elfii DSM9442. The data show that the metabolism of P. elfii DSM9442 is optimized when grown at 20 MPa, in agreement with its piezophilic nature. Both Pseudothermotoga strains form chained cells when the hydrostatic pressure increases, especially P. elfii DSM9442 for which 44% of cells is chained when grown at 40 MPa. The viability of the chained cells increases with the increase in the hydrostatic pressure, indicating that chain formation is a protective mechanism for P. elfii DSM9442.

In situ observations and modelling revealed environmental factors favouring occurrence of Vibrio in microbiome of the pelagic Sargassum responsible for strandings

Historically, pelagic Sargassum were only found in the Sargasso Sea. Since 2011, blooms were regularly observed in warmer water, further south. Their developments in Central Atlantic are associated with mass strandings on the coasts, causing important damages and potentially dispersion of new bacteria. Microbiomes associated with pelagic Sargassum were analysed at large scale in Central Atlantic and near Caribbean Islands with a focus on pathogenic bacteria. Vibrio appeared widely distributed among pelagic Sargassum microbiome of our samples with higher occurrence than previously found in Mexico Gulf. Six out the 16 Vibrio-OTUs (Operational Taxonomic Unit), representing 81.2 ± 13.1% of the sequences, felt in cluster containing pathogens. Among the four different microbial profiles of pelagic Sargassum microbiome, Vibrio attained about 2% in two profiles whereas it peaked, in the two others, at 6.5 and 26.8% respectively, largely above the concentrations found in seawater surrounding raft (0.5%). In addition to sampling and measurements, we performed backward Lagrangian modelling of trajectories of rafts, and rebuilt the sampled rafts environmental history allowing us to estimate Sargassum growth rates along raft displacements. We found that Vibrio was favoured by high Sargassum growth rate and in situ ammonium and nitrite, modelled phosphate and nitrate concentrations, whereas zooplankters, benthic copepods, and calm wind (proxy of raft buoyancy near the sea surface) were less favourable for them. Relations between Vibrio and other main bacterial groups identified a competition with Alteromonas. According to forward Lagrangian tracking, part of rafts containing Vibrio could strand on the Caribbean coasts, however the strong decreases of modelled Sargassum growth rates along this displacement suggest unfavourable environment for Vibrio. For the conditions and areas observed, the sanitary risk seemed in consequence minor, but in other areas or conditions where high Sargassum growth rate occurred near coasts, it could be more important.

Hydrostatic Pressure Helps to Cultivate an Original Anaerobic Bacterium From the Atlantis Massif Subseafloor (IODP Expedition 357): Petrocella atlantisensis gen. nov. sp. nov

Rock-hosted subseafloor habitats are very challenging for life, and current knowledge about microorganisms inhabiting such lithic environments is still limited. This study explored the cultivable microbial diversity in anaerobic enrichment cultures from cores recovered during the International Ocean Discovery Program (IODP) Expedition 357 from the Atlantis Massif (Mid-Atlantic Ridge, 30°N). 16S rRNA gene survey of enrichment cultures grown at 10–25°C and pH 8.5 showed that Firmicutes and Proteobacteria were generally dominant. However, cultivable microbial diversity significantly differed depending on incubation at atmospheric pressure (0.1 MPa), or hydrostatic pressures (HP) mimicking the in situ pressure conditions (8.2 or 14.0 MPa). An original, strictly anaerobic bacterium designated 70B-A^T was isolated from core M0070C-3R1 (1150 meter below sea level; 3.5 m below seafloor) only from cultures performed at 14.0 MPa. This strain named Petrocella atlantisensis is a novel species of a new genus within the newly described family Vallitaleaceae (order Clostridiales, phylum Firmicutes). It is a mesophilic, moderately halotolerant and piezophilic chemoorganotroph, able to grow by fermentation of carbohydrates and proteinaceous compounds. Its 3.5 Mb genome contains numerous genes for ABC transporters of sugars and amino acids, and pathways for fermentation of mono- and di-saccharides and amino acids were identified. Genes encoding multimeric [FeFe] hydrogenases and a Rnf complex form the basis to explain hydrogen and energy production in strain 70B-A^T. This study outlines the importance of using hydrostatic pressure in culture experiments for isolation and characterization of autochthonous piezophilic microorganisms from subseafloor rocks.

Pressure-Retaining Sampler and High-Pressure Systems to Study Deep-Sea Microbes Under in situ Conditions

The pelagic realm of the dark ocean is characterized by high hydrostatic pressure, low temperature, high-inorganic nutrients, and low organic carbon concentrations. Measurements of metabolic activities of bathypelagic bacteria are often underestimated due to the technological limitations in recovering samples and maintaining them under in situ environmental conditions. Moreover, most of the pressure-retaining samplers, developed by a number of different labs, able to maintain seawater samples at in situ pressure during recovery have remained at the prototype stage, and therefore not available to the scientific community. In this paper, we will describe a ready-to-use pressure-retaining sampler, which can be adapted to use on a CTD-carousel sampler. As well as being able to recover samples under in situ high pressure (up to 60 MPa) we propose a sample processing in equi-pressure mode. Using a piloted pressure generator, we present how to perform sub-sampling and transfer of samples in equi-pressure mode to obtain replicates and perform hyperbaric experiments safely and efficiently (with <2% pressure variability). As proof of concept, we describe a field application (prokaryotic activity measurements and incubation experiment) with samples collected at 3,000m-depth in the Mediterranean Sea. Sampling, sub-sampling, transfer, and incubations were performed under in situ high pressure conditions and compared to those performed following decompression and incubation at atmospheric pressure. Three successive incubations were made for each condition using direct dissolved-oxygen concentration measurements to determine the incubation times. Subsamples were collected at the end of each incubation to monitor the prokaryotic diversity, using 16S-rDNA/rRNA high-throughput sequencing. Our results demonstrated that oxygen consumption by prokaryotes is always higher under in situ conditions than after decompression and incubation at atmospheric pressure. In addition, over time, the variations in the prokaryotic community composition and structure are seen to be driven by the different experimental conditions. Finally, within samples maintained under in situ high pressure conditions, the active (16S rRNA) prokaryotic community was dominated by sequences affiliated with rare families containing piezophilic isolates, such as Oceanospirillaceae or Colwelliaceae. These results demonstrate the biological importance of maintaining in situ conditions during and after sampling in deep-sea environments.

Bacterial Bioluminescence: Light Emission in Photobacterium phosphoreum Is Not Under Quorum-Sensing Control

Bacterial-bioluminescence regulation is often associated with quorum sensing. Indeed, many studies have been made on this subject and indicate that the expression of the light-emission-involved genes is density dependent. However, most of these studies have concerned two model species, Aliivibrio fischeri and Vibrio campbellii. Very few works have been done on bioluminescence regulation for the other bacterial genera. Yet, according to the large variety of habitats of luminous marine bacteria, it would not be surprising to find different light-regulation systems. In this study, we used Photobacterium phosphoreum ANT-2200, a piezophilic bioluminescent strain isolated from Mediterranean deep-sea waters (2200-m depth). To answer the question of whether or not the bioluminescence of P. phosphoreum ANT-2200 is under quorum-sensing control, we focused on the correlation between growth and light emission through physiological, genomic and, transcriptomic approaches. Unlike A. fischeri and V. campbellii, the light of P. phosphoreum ANT-2200 immediately increases from its initial level. Interestingly, the emitted light increases at much higher rate at the low cell density than it does for higher cell-density values. The expression level of the light-emission-involved genes stays constant all along the exponential growth phase. We also showed that, even when more light is produced, when the strain is cultivated at high hydrostatic pressure, no change in the transcription level of these genes can be detected. Through different experiments and approaches, our results clearly indicate that, under the tested conditions, the genes, directly involved in the bioluminescence in P. phosphoreum ANT-2200, are not controlled at a transcriptomic level. Quite obviously, these results demonstrate that the light emission of the strain is not density dependent, which means not under quorum-sensing control. Through this study, we point out that bacterial-bioluminescence regulation should not, from now on, be always linked with the quorum-sensing control.

Delivery room management of extremely preterm infants: the EPIPAGE-2 study

OBJECTIVE

To analyse the delivery room management of babies born between 22 and 26 weeks of completed gestational age and to identify the factors associated with the withholding or withdrawal of intensive care.

STUDY DESIGN

Population-based cohort study.

PATIENTS AND METHODS

Our study population comprised 2145 births between 22 and 26 completed weeks enrolled in the EPIPAGE-2 study, a French cohort of very preterm infants born in 2011. The primary outcome measure was withholding or withdrawal of intensive care in the delivery room.

RESULTS

Among infants born alive at 22-23 weeks, intensive care was withheld or withdrawn for >90%. At 24 weeks, resuscitative measures were withheld or withdrawn for 38%, at 25 weeks for 8% and at 26 weeks for 3%. Other factors besides gestational age at birth associated with this withholding or withdrawal for infants born at 24-26 weeks were birth weight <600 g, emergency delivery (within 24 h of the mother's admission) and singleton pregnancy. Although rates of withholding or withdrawal of intensive care varied substantially between maternity units (from 0% to 100%), the variability was primarily explained by differences in distributions of gestational age at birth.

CONCLUSIONS

Although gestational age is only one factor predicting survival of preterm infants, practices in France appear to be based primarily on this factor, which thus has direct effects on the survival of extremely preterm infants. The ethical implications of basing life and death decisions only on gestational age before 25 weeks require further examination.

Genomic and physiological analysis reveals versatile metabolic capacity of deep-sea Photobacterium phosphoreum ANT-2200

Bacteria of the genus Photobacterium thrive worldwide in oceans and show substantial eco-physiological diversity including free-living, symbiotic and piezophilic life styles. Genomic characteristics underlying this variability across species are poorly understood. Here we carried out genomic and physiological analysis of Photobacterium phosphoreum strain ANT-2200, the first deep-sea luminous bacterium of which the genome has been sequenced. Using optical mapping we updated the genomic data and reassembled it into two chromosomes and a large plasmid. Genomic analysis revealed a versatile energy metabolic potential and physiological analysis confirmed its growth capacity by deriving energy from fermentation of glucose or maltose, by respiration with formate as electron donor and trimethlyamine N-oxide (TMAO), nitrate or fumarate as electron acceptors, or by chemo-organo-heterotrophic growth in rich media. Despite that it was isolated at a site with saturated dissolved oxygen, the ANT-2200 strain possesses four gene clusters coding for typical anaerobic enzymes, the TMAO reductases. Elevated hydrostatic pressure enhances the TMAO reductase activity, mainly due to the increase of isoenzyme TorA1. The high copy number of the TMAO reductase isoenzymes and pressure-enhanced activity might imply a strategy developed by bacteria to adapt to deep-sea habitats where the instant TMAO availability may increase with depth.

Transcriptomics reveal several gene expression patterns in the piezophile Desulfovibrio hydrothermalis in response to hydrostatic pressure

RNA-seq was used to study the response of Desulfovibrio hydrothermalis, isolated from a deep-sea hydrothermal chimney on the East-Pacific Rise at a depth of 2,600 m, to various hydrostatic pressure growth conditions. The transcriptomic datasets obtained after growth at 26, 10 and 0.1 MPa identified only 65 differentially expressed genes that were distributed among four main categories: aromatic amino acid and glutamate metabolisms, energy metabolism, signal transduction, and unknown function. The gene expression patterns suggest that D. hydrothermalis uses at least three different adaptation mechanisms, according to a hydrostatic pressure threshold (HP_t) that was estimated to be above 10 MPa. Both glutamate and energy metabolism were found to play crucial roles in these mechanisms. Quantitation of the glutamate levels in cells revealed its accumulation at high hydrostatic pressure, suggesting its role as a piezolyte. ATP measurements showed that the energy metabolism of this bacterium is optimized for deep-sea life conditions. This study provides new insights into the molecular mechanisms linked to hydrostatic pressure adaptation in sulfate-reducing bacteria.

Effects of hydrostatic pressure on growth and luminescence of a moderately-piezophilic luminous bacteria Photobacterium phosphoreum ANT-2200

Bacterial bioluminescence is commonly found in the deep sea and depends on environmental conditions. Photobacterium phosphoreum ANT-2200 has been isolated from the NW Mediterranean Sea at 2200-m depth (in situ temperature of 13°C) close to the ANTARES neutrino telescope. The effects of hydrostatic pressure on its growth and luminescence have been investigated under controlled laboratory conditions, using a specifically developed high-pressure bioluminescence system. The growth rate and the maximum population density of the strain were determined at different temperatures (from 4 to 37°C) and pressures (from 0.1 to 40 MPa), using the logistic model to define these two growth parameters. Indeed, using the growth rate only, no optimal temperature and pressure could be determined. However, when both growth rate and maximum population density were jointly taken into account, a cross coefficient was calculated. By this way, the optimum growth conditions for P. phosphoreum ANT-2200 were found to be 30°C and, 10 MPa defining this strain as mesophile and moderately piezophile. Moreover, the ratio of unsaturated vs. saturated cellular fatty acids was found higher at 22 MPa, in agreement with previously described piezophile strains. P. phosphoreum ANT-2200 also appeared to respond to high pressure by forming cell aggregates. Its maximum population density was 1.2 times higher, with a similar growth rate, than at 0.1 MPa. Strain ANT-2200 grown at 22 MPa produced 3 times more bioluminescence. The proposed approach, mimicking, as close as possible, the in situ conditions, could help studying deep-sea bacterial bioluminescence and validating hypotheses concerning its role into the carbon cycle in the deep ocean.

The first genomic and proteomic characterization of a deep-sea sulfate reducer: insights into the piezophilic lifestyle of Desulfovibrio piezophilus

Desulfovibrio piezophilus strain C1TLV30(T) is a piezophilic anaerobe that was isolated from wood falls in the Mediterranean deep-sea. D. piezophilus represents a unique model for studying the adaptation of sulfate-reducing bacteria to hydrostatic pressure. Here, we report the 3.6 Mbp genome sequence of this piezophilic bacterium. An analysis of the genome revealed the presence of seven genomic islands as well as gene clusters that are most likely linked to life at a high hydrostatic pressure. Comparative genomics and differential proteomics identified the transport of solutes and amino acids as well as amino acid metabolism as major cellular processes for the adaptation of this bacterium to hydrostatic pressure. In addition, the proteome profiles showed that the abundance of key enzymes that are involved in sulfate reduction was dependent on hydrostatic pressure. A comparative analysis of orthologs from the non-piezophilic marine bacterium D. salexigens and D. piezophilus identified aspartic acid, glutamic acid, lysine, asparagine, serine and tyrosine as the amino acids preferentially replaced by arginine, histidine, alanine and threonine in the piezophilic strain. This work reveals the adaptation strategies developed by a sulfate reducer to a deep-sea lifestyle.

Assimilation of marine extracellular polymeric substances by deep-sea prokaryotes in the NW Mediterranean Sea

This study examined total uptake of extracellular polymeric substances (EPS) and glucose and the percentage of prokaryotic cells (Bacteria, Crenarchaea and Euryarchaea) consuming these compounds in the major water masses at the DYFAMED site (NW Mediterranean Sea). The potential assimilation rates of EPS at 10 m depth were higher but on the same order of magnitude as those at 2000 m depth (from 43.4 to 29.0 pmol l(-1)  h(-1) ). In contrast, glucose assimilation rates decreased with depth from 49.4 to 0.07 pmol l(-1)  h(-1) at 10 and 2000 m depth respectively. Microautoradiography analyses indicated similar percentages of active cells assimilating EPS at 10 and 2000 m depth (13% and 10% of the total-cells). The combination of microautoradiography and catalysed reporter deposition fluorescence in situ hybridization (MICRO-CARD-FISH) analyses revealed that the percentages of Bacteria assimilating (3) H-carbohydrates decreased with depth by twofold for EPS. In contrast, the contribution by Euryarchaea to EPS consumption increased with depth by sixfold. At 2000 m, 50% of active cells consuming (3) H-carbohydrates were Euryarchaea. These data highlight potential differences in the roles of Bacteria and Archaea in the deep sea biogeochemical cycles and shed light on the importance of deep-sea Euryarchaea in the degradation of dissolved organic matter.

Desulfovibrio piezophilus sp. nov., a piezophilic, sulfate-reducing bacterium isolated from wood falls in the Mediterranean Sea

A novel sulfate-reducing bacterium, designated C1TLV30T, was isolated from wood falls at a depth of 1693 m in the Mediterranean Sea. Cells were motile vibrios (2–4×0.5 µm). Strain C1TLV30T grew at temperatures between 15 and 45 °C (optimum 30 °C) and at pH 5.4–8.6 (optimum 7.3). It required NaCl for growth (optimum at 25 g NaCl l−1) and tolerated up to 80 g NaCl l−1. Strain C1TLV30T used as energy sources: lactate, fumarate, formate, malate, pyruvate and ethanol. The end products from lactate oxidation were acetate, H2S and CO2 in the presence of sulfate as terminal electron acceptor. Besides sulfate, thiosulfate and sulfite were also used as terminal electron acceptors, but not elemental sulfur, fumarate, nitrate or nitrite. Strain C1TLV30T possessed desulfoviridin and was piezophilic, growing optimally at 10 MPa (range 0–30 MPa). The membrane lipid composition of this strain was examined to reveal an increase in fatty acid chain lengths at high hydrostatic pressures. The G+C content of the genomic DNA was 49.6 % and the genome size was estimated at 3.5±0.5 Mb. Phylogenetic analysis of the SSU rRNA gene sequence indicated that strain C1TLV30T was affiliated to the genus Desulfovibrio with Desulfovibrio profundus being its closest phylogenetic relative (similarity of 96.4 %). On the basis of SSU rRNA gene sequence comparisons and physiological characteristics, strain C1TLV30T ( = DSM 21447T  = JCM 1548T) is proposed to be assigned to a novel species of the genus Desulfovibrio, Desulfovibrio piezophilus sp. nov.

Age-related male reproductive effort in two mountain ungulates of contrasting sexual size dimorphism

In polygynous ungulates, the reproductive effort of adult males peaks during a short period in which feeding activities are sacrificed for mating activities. Hence, both fat reserves and body mass are predicted to decline markedly during this period. The decline is also predicted to be greater in fat reserves than in body mass because fat is catabolized before muscle, and to increase with the intensity of sexual selection. In contrast, no specific patterns are expected in females for which late gestation and lactation rather than mating are the energetically most demanding periods. We tested these hypotheses in two mountain ungulates of contrasting sexual size dimorphism (SSD): Himalayan tahr ( Hemitragus jemlahicus (H. Smith, 1826)) (SSD = 123%) and alpine chamois ( Rupicapra rupicapra (L., 1758)) (SSD = 26%). As expected, kidney fat declined more rapidly than body mass in adult males of both species. Kidney fat declined faster in adult male tahr compared with adult male chamois. There was no consistent pattern of changes in body mass or kidney fat in female tahr or female chamois. Our results suggest that adult males of species with strong SSD allocate more energy to mating than males of less dimorphic species.

Daily responses of mouflon (Ovis gmelini musimon ×Ovis sp.) activity to summer climatic conditions

Investigating the factors shaping the activity of large herbivores is of prime importance because changes in their activity patterns may indicate physiological stress, which can affect reproduction and survival of individuals, and thereby population growth. Although climatic conditions are known to impact the activity patterns of large herbivores, few studies have investigated this relationship at a fine temporal scale. From a continuous monitoring of activity, we assessed the influence of temperature and wind on the summer activity of female mouflon ( Ovis gmelini musimon Pallas, 1811 × Ovis  sp.) facing summer droughts. Females showed a marked bimodal activity pattern, with activity peaks occurring after dawn and before dusk. When temperature increased and wind speed decreased, the morning activity peak occurred earlier, while the evening activity peak was delayed. Hence, under stressing climatic conditions, female mouflon decreased their diurnal activity while increasing their nocturnal activity. However, this nocturnal increase did not prevent the activity rate over 24 h to decrease during hot nonwindy days compared with cool windy days. Although the occurrence of wind mitigated the negative influence of heat on the diurnal activity, wind had no effect at the daily scale. These findings emphasize the importance of working at different temporal scales when assessing the activity patterns of free-ranging vertebrates.

Ethical decision-making for extremely preterm deliveries: results of a qualitative survey among obstetricians and midwives

OBJECTIVE

To explore the practices, attitudes and feelings of obstetricians and midwives in cases of extreme prematurity.

METHODS

A qualitative study was conducted as part of a European Concerted Action (EUROBS) in three tertiary-care maternity units, located in three cities in the northern, southern and central areas of France. Semi-structured interviews lasted an average of 60 min and were tape-recorded. They were independently analyzed by two different researchers using a content analysis. All full-time obstetricians and half of the full-time midwives were eligible for the study. Overall, 17 obstetricians and 30 midwives participated.

RESULTS

Both obstetricians and midwives considered that decision-making in case of very preterm births raised ethical problems concerning the mother and the fetus. Despite some birth weight and gestational age criteria defined in advance, management around delivery appeared to be decided on a case-by-case basis. At birth, the neonatologists made the decisions. They were perceived as being more inclined than the obstetric team to initiate intensive care. If the child was born alive, intensive care was started, in the knowledge that it could be withdrawn later, if appropriate. Parents were sometimes involved in decision-making during pregnancy, in particular when there was no emergency situation. Compared with obstetricians, midwives tended to have a less favorable perception of the neonatologists' practices, and to report less parental involvement in decision-making.

CONCLUSIONS

Decisions about the obstetric management and resuscitation of extremely preterm infants are usually made on a case-by-case basis. Parents are sometimes involved in decision-making. Midwives express serious concerns about the current practices.

Determinants of seasonal variation in activity patterns of mouflon

Balancing energetic requirements is a complex process governed by the current condition of the animal, its physiological state, and by the local environment. In response to these factors, animals are expected to adapt their activity patterns. Based on continuous monitoring of 14 GPS-collared animals in southern France, we studied how environmental conditions and reproductive life-cycle periods shape the monthly activity patterns of free-ranging female mouflon ( Ovis gmelini musimon  × Ovis sp. (Blyth, 1841)). More specifically, we analyzed total daily activity, diurnal activity, length of activity bouts, and number of activity bouts. We performed multivariate analyses to account for the relationship between several intercorrelated explanatory variables and monthly activity variables. Mouflon decreased their daily activity, diurnal activity, and length of activity bouts during the hot summer months. Such changes might allow animals to reduce thermoregulation costs. The resulting higher activity in winter compared with summer indicates that summer is the most limiting period for large herbivores in Mediterranean area. Both the number of active bouts and the daily activity increased during spring, when females have access to increased food quality, which ensures a faster digestion, and when they may face high energetic requirements owing to reproduction.

Problèmes éthiques posés par l'extrême prématurité: résultats d'une étude qualitative auprès des obstétriciens et des sages-femmes

OBJECTIVE

Our objective was to explore the practices, attitudes and feelings of obstetricians and midwives in case of extreme prematurity.

POPULATION AND METHODS

A qualitative study was conducted as part of a European Concerted Action (EUROBS) in 1999 and 2000 in three tertiary-care maternity units, located in three cities in the northern, southern and central areas of France respectively. Semi-structured, tape-recorded interviews were conducted and were independently analysed by two different researchers using a content analysis. All full-time obstetricians and half of the full-time midwives were eligible for the study. Overall, 17 obstetricians and 30 midwives participated.

RESULTS

Both obstetricians and midwives considered that decision-making in case of very preterm births raised ethical problems concerning the mother and the foetus. Despite some birth weight and gestational age criteria defined in advance, management around delivery appeared to be decided on a case-by-case basis. At birth, the neonatologists made the decisions. They were perceived as more inclined than the obstetrical team to initiate intensive care. If the child was born alive, intensive care was started, knowing that it could be withdrawn later, if appropriate. Parents were sometimes involved in decision-making during pregnancy, less frequently at birth or after birth.

DISCUSSION AND CONCLUSION

Compared with obstetricians, midwives tended to have a less favourable perception of the neonatologists' practices, and to deplore the lack of parental information and involvement in decision-making. Decisions about the obstetrical management and resuscitation of extremely preterm infants are essentially always made on a case-by-case basis. Parents are sometimes involved in decision-making. Midwives express serious concerns about the current practices.

Mothers' psychological distress 1 year after very preterm childbirth. Results of the EPIPAGE qualitative study

BACKGROUND

The objectives of this study were to assess qualitatively mothers' physical and psychological health, their perception of their child's health and development, and their difficulties with childcare from 2 months post discharge to 1 year after a very preterm delivery.

METHODS

The study population included all mothers who delivered before 33 weeks of amenorrhea between November 1998 and November 1999 in a Parisian maternity unit and between February 2000 and February 2001 in a maternity unit located in Rouen (France). Twenty-one of the 38 mothers contacted agreed to participate (55%). Semi-structured interviews were conducted by a clinical psychologist at the woman's home. They were taped, fully transcribed and subjected to content analysis.

RESULTS

The main difficulties reported by mothers at 1 year were fatigue, depressive mood, anxiety and physical symptoms. Depressive mood was associated with social isolation, post-traumatic symptoms, withdrawal and feelings of guilt. Most mothers also described their child as being difficult and tiring. Mothers' reports about their own health and difficult behaviour of their child were more negative at 1 year than at 2 months post discharge.

CONCLUSIONS

The mothers' psychological distress following a very preterm birth did not improve between 2 months post discharge and 1 year after delivery. Comprehensive follow-up care programmes should take into account this consequence of a very preterm birth and provide access to adequate psychological support, care or treatment.

French midwives' practice of termination of pregnancy for fetal abnormality. At what psychological and ethical cost?

OBJECTIVES

To study the clinical, emotional and moral difficulties that French midwives encounter in the labor ward while performing termination of pregnancy (TOP) for fetal abnormality.

SETTING

Six public maternity hospitals located in the Ile de France region, two of which were referral centers for prenatal diagnosis (PND) and TOP.

METHOD

Questionnaire survey

RESULTS

Ninety-two of 115 midwives responded. Sixty-five percent of the midwives reported that their role in the labor ward during TOP was difficult. Aspects contributing substantially to the perceived difficulties were the midwives' responsibility to provide psychological support to patients and the emotional distress of the midwives themselves. Seventy-five percent reported that they were concerned about the child being alive in cases of late TOP. Twenty-five percent of the midwives reported moral conflicts due to personal, cultural or religious background, mainly for particular indications. There was a consensus about the clinical management of TOP. Overall, midwives with professional experience, training, and those who worked in a referral center reported fewer difficulties.

CONCLUSION

It is necessary to improve institutional support available within maternity units to alleviate the difficulties midwives face in their roles. The need for training/updating midwives about psychological and ethical aspects of TOP should also be considered.

Conséquences psychologiques des naissances multiples

Since the mid 1970s, the number of multiple births has dramatically increased in our country and most European countries. This paper summarizes the psychological consequences of multiple births based on a review of the literature and on our clinical experience. During pregnancy mothers experience great physical problems linked with increased medical risks for themselves and for the children. These risks cause psychological difficulties: hospitalisation and separation from the family, fear of a premature delivery and anxiety for the children. After delivery the children are often hospitalized, which makes the attachment process difficult. The mortality of multiple children is high and mourning for one child creates particular problems for parents who simultaneously face grieving and attachment processes. After hospital discharge, the overload of work mothers experience leads to physical and nervous fatigue, which does not make easier individual relationship with the children. Mothers have a high level of psychological vulnerability and an increased risk of depression. The satisfactory development of each twin or triplet child requires individualized relationship with his/her mother and his/her father. That is how he/she will be able to build his/her identity and future autonomy. It is important to be aware of the problems experienced by the families and to improve the way material help and psychological support are provided to them.

Women's interpretation of an abnormal result on measurement of fetal nuchal translucency and maternal serum screening for prenatal testing of Down syndrome

OBJECTIVE

To assess the effects of sociodemographic and health-provider factors on women's understanding of abnormal results on measurement of nuchal translucency (NT) and maternal serum screening (MSS), 18 months after the implementation of a policy aimed at increasing women's awareness regarding MSS.

METHODS

A representative sample of women (n = 734) who gave birth in Parisian maternity units in 1999 were asked about their understanding of an abnormal result on MSS and NT. We assessed the effects of sociodemographic and health-provider factors on the probability of women interpreting an abnormal result correctly, misinterpreting it as a definitive diagnosis, or declaring that they did not know how to interpret the result. Response rate was 92% and the analyses included multinomial models.

RESULTS

For both MSS and NT measurement, the majority of women interpreted an abnormal result correctly. However, there were substantial sociodemographic differences in the probability of women interpreting an abnormal result correctly, and more so in the probability of their declaring not to know how to interpret the result. The probability of correct interpretations was substantially higher, and that of declaring not to know how to interpret the result substantially lower, for MSS than NT measurement. However, for several sociodemographic groups, the proportion of women who misinterpreted an abnormal result on screening as indicative of a definitive diagnosis was also higher for MSS as compared with NT measurement.

CONCLUSIONS

These findings underscore the need for additional efforts, along with alternative strategies, to inform women about the implications of prenatal screening, particularly in the case of measurement of NT.

Difficultés de suivi d'une cohorte d'enfants nés grands prématurés : EPIPAGE Paris–Petite-Couronne

OBJECTIVES

To describe the characteristics of the children of parents who did not respond to a follow-up questionnaire in a cohort of very preterm infants (EPIPAGE study) and to explore the reasons why they did not complete the questionnaires.

METHODS

The non-respondents (N = 176) were the parents who did not return the questionnaires at 1 and 2 years. Contacts were organised by telephone calls and at home visits.

RESULTS

The families of the non-respondents presented more socioeconomic difficulties and their children were born more preterm than those followed up without difficulties. The efforts made to contact the non-respondents revealed that their families were often confronted with major adverse socioeconomic difficulties, had severe illnesses and psychological troubles. Half of the children of the non-respondents were finally examined at the 5-year assessment. They showed lower performances at the cognitive development test and a poorer health status than the children of the respondents.

CONCLUSION

When the follow-up does not include the initial population in its totality, the socioeconomic difficulties are underestimated and probably also the rate of sequelae associated with very preterm delivery.

The effects of a severe drought on mouflon lamb survival

The mouflon population of Caroux-Espinouse, southern France, inhabits a highly seasonal area with dry summers. We monitored summer lamb survival during a severe drought in 2003, from early June to late August. The survival of 35 radio-tagged lambs over nine two-week periods was strongly affected by the timing of rainfall. Survival depended on the amount of rainfall recorded at a given 14 day period and in the previous 14-21 day period. Survival was not influenced by the exceptionally high mean daily temperature recorded during some periods. Male lamb survival (0.68) tended to be less than female survival (0.81), although not significantly, possibly because of a low sample size. The high lamb mortality (25.7%) recorded during a four-month period is much higher than previous estimates of first-year mortality (less than 10%). We recommend accounting for climatic variation in summer when studying the population dynamics of ungulates.

[Consequences for the family of a very preterm birth two months after discharge. Results of the EPIPAGE qualitative study]

OBJECTIVES

To assess mothers' and fathers' psychological health 2 months after discharge of a very preterm infant. To describe the problems encountered with the child, the quality of the marital relationship, the organization of the family and to compare the answers made by mothers and fathers.

POPULATION

Mothers having delivered before 33 weeks in two maternity units in Paris and in Rouen were contacted. Among the 38 mothers who were eligible, 21 accepted to participate. Their children were born between 26 weeks and 32 weeks and weighted from 630 to 2100 g.

METHOD

A semi-structured interview was conducted at home by a psychologist with each member of the couple. It lasted approximately 1 h. Each interview was tape-recorded and fully transcribed. The analysis allowed to discover the main themes emerging from the interviews and to search for the role of factors.

RESULTS

Two months after discharge, mothers expressed anxiety and feelings of depression. Fathers noted considerable fatigue and both parents expressed concerns about the child's health and development. Marital dissatisfaction and behavioural symptoms in siblings were also noted. Mothers' difficulties were not linked to the degree of prematurity or length of stay in neonatal unit but with the baby's present health state, his rehospitalizations and maternal characteristics such as isolation, lack of support and previous perinatal loss. The mother's psychological organisation modifies the role of objective factors. Fathers seemed more able to cope with and overcome the traumatic event caused by the very preterm birth. They insisted on their role of support for the mother and the mother-child relationship.

CONCLUSION

The consequences of a very preterm birth are important and concern the whole family. After hospital discharge, the follow-up care of the very preterm baby should take the family social and psychological situation into account.

Ethical decision-making in prenatal diagnosis and termination of pregnancy: a qualitative survey among physicians and midwives

OBJECTIVES

This study was aimed at exploring the conflicts and ethical problems experienced by professionals involved in prenatal diagnosis and termination of pregnancy (TOP) in order to improve the understanding of decision-making processes and medical practices in the field of prenatal diagnosis.

METHODS

Qualitative study with in-depth tape-recorded interviews conducted in three tertiary care maternity units in France, between May 1999 and March 2000. All full-time obstetricians and half of the full-time midwives were contacted. Seventeen obstetricians and 30 midwives participated (three refusals, five missing). Interviews were transcribed and analysed successively by two different researchers.

RESULTS

All respondents stated that prenatal diagnosis and TOP raised important ethical dilemmas, the most frequent being request for abortion in case of minor anomalies. They pointed out the inability of our society to appropriately care for disabled children and the risk of eugenic pressures. The decisions and practices in prenatal diagnosis should be debated throughout society. All respondents reported that their unit did not have protocols for deciding when a TOP was justifiable. The transmission of information to the women appeared to be a problematic area. Moral conflicts and emotional distress were frequently expressed, especially by midwives who mentioned the need for more discussions and support groups in their department.

CONCLUSION

Health professionals involved in prenatal diagnosis face complex ethical dilemmas which raise important personal conflicts. A need for more resources for counselling women and for open debate about the consequences of the current practices clearly emerged.

Mothers' knowledge of screening for trisomy 21 in 1999: a survey in Paris maternity units

OBJECTIVE

To assess mothers' knowledge of screening tests for trisomy 21.

STUDY DESIGN

Interview of all women who had recently delivered a healthy child and were present in 15 Paris maternity units during one of the two non-consecutive days in June 1999 (N = 734).

RESULTS

Two-third said that they had access to a nuchal translucency measurement (NTM) and to maternal serum screening (MSS), and 16% to amniocentesis. Thirty-eight percent of the women who had NTMs and 69% of those who had serum screening said that they had been informed of the need for amniocentesis if the results were abnormal. Among the women who had amniocentesis, 20% did not know the risk of miscarriage and 41% had not been informed about the possibility of terminating the pregnancy if trisomy 21 was diagnosed.

CONCLUSIONS

Mothers' knowledge about the screening tests for trisomy 21 remains fragmentary. Providing comprehensive information about all these tests should be considered in early pregnancy so that women can make informed choices.

[Psychological consequences of twinship on the children and their parents]

This paper presents a synthesis about the psychological consequences of twinship based on a review of the literature and on our clinical experience. During pregnancy, delivery and the immediate post-partum, mothers experience physical and psychological difficulties linked with increased medical risks for themselves and for the children. The twins mortality is high before and after delivery. Grieving for one twin creates particular problems for parents. During first months after hospital discharge mothers encounter material and emotional stress. They are caused by overload of mothering tasks and the specificity of mother-twins relationship. The impossibility to establish a dyadic relationship with each child creates feelings of frustration and guilt. The risk of child abuse is increased in twins. The balanced psychoemotional development of twins requires parental attitudes enhancing their individualization as opposed to their "collectivization". The risk of prematurity is ten times increased in twins which increases the risks of developmental disabilities. Considering that the number of twin deliveries is rising in our country it is important to be aware of the problems experienced by the families and to improve the way material and psychological help is provided to them.

[Patients' and professionals'opinions on third trimester termination of pregnancy]

The aims of this paper are to present a review of the literature on the patients'and professionals'opinions about third trimester termination of pregnancy and to give the main results of two studies that we have recently conducted. On the whole, publications indicate that the patients'distress is not linked with the moment when pregnancy is terminated. However questions about the fetus death, in utero feticide, and the organization of funerals remain sensitive and communication with patients on these matters needs to be improved. Studies in other countries indicate that professionals are not prepared to recommend late terminations of pregnancy mainly because the fetus is viable and should be considered as a patient. The mother's and the couple's point of view seem not to be enough taken into account. French obstetricians seem to consider more acceptable third trimester TOP than their european colleagues. For them, not setting a limit to the gestational age allows more thorough evaluation of the diagnosis and more parental reflection. They mention major ethical dilemmas, independently from gestational age, and suggest that current practices should be openly debated.

[Opinions of couples on care during medical termination of pregnancy]

OBJECTIVES

To study the medical care, staff attitudes and patients' satisfaction from the decision to the post-intervention medical visit for termination of pregnancy for fetal abnormalies.

PATIENTS AND METHODS

All patients and their spouses having a termination of pregnancy at the "Unite de Medecine Foetale" in Port-Royal Hospital between November 1996 and July 1997 were contacted for the study. A self-administered questionnaire was mailed six to eight weeks after intervention. Forty seven women and 42 men returned a completed questionnaire, the response rates were respectively 68% and 61%.

RESULTS

The patients and their spouses rated globally very high their satisfaction about the care received. The delay before intervention, the length and pain of labour were rated less positively. The factors associated with satisfaction were the quality of the relationship with the staff, and of information. Positive feelings about delivery were linked with the consideration and relief of pain. Most respondents mentioned that their physical and psychological state has improved at the moment of the survey but the psychological distress subsisted or has increased in one fourth of the cases. On the whole the answers made within the couples were correlated.

CONCLUSION

The positive results should be moderated by the number of non-respondents. In a context of very high rates of satisfaction, psychological distress is still present for one respondent out of four, six to eight weeks after termination of pregnancy for fetal abnormalies.

Development and behaviour of seven-year-old triplets

The aim of this study was to assess the development and behaviour of 7-y-old triplets, who were followed from delivery to 7 y of age. The McCarthy Scales of Children's Abilities (MSCA) and Achenbach's Child Behaviour Checklist (CBCL) were used to assess and compare development and behaviour in the triplets and in a control group of singletons. The sample included 33 sets of triplets and 33 singletons, all 7-y-olds, and comparable for sex and fathers' social class. The triplets' scores on the MSCA were all within normal range. Although their mean scores for all subtests were below those of singletons, they did not differ significantly. The mean CBCL scores, based on mothers' reports, indicated that the triplets had significantly fewer behavioural problems than the controls. In half the triplet sets, one child stood out as having more behavioural problems than the others.

CONCLUSION

Further assessments of the development of triplets are needed; these should be based on larger study samples and should use information from teachers and external observers as well as mothers.

[Mothers of triplets and their children: course from 4 to 7 years after birth]

OBJECTIVES

To study the psychological health of the mothers and their difficulties seven years after the birth of triplets and to compare these results with those obtained at four years.

DATA AND METHODS

Eleven mothers of triplets were followed up from birth to seven. At four and seven years the psychological status of the mothers and their relationships with the triplets were evaluated using a semi-structured interview and the level of depression was measured using a standardized scale (CES-D). At seven years the scores were compared to those of mothers having a singleton child of the same age.

RESULTS

At seven years three mothers of triplets out of 11 still suffered of depressive symptoms. These symptoms were more frequent than among control mothers but non significantly. One mother of triplets out of two (6/11), twice more than at four years, appreciated the increase of her educative tasks and the decrease of practical problems. In the other half of the sample problems still persisted between adults and children.

CONCLUSION

Although the situation seemed to improve at seven years, the mother's psychological distress and quality of relationship with the children remained preoccupying in one family out of two.

[Ethical decisions making in neonatal intensive care. Survey among nursing staff in 2 French centers]

A European Concerted Action, Euronic, has been set up to study the attitudes and self-reported practices of the staff working in neonatal intensive care units about parent's information and ethical decisionmaking. This paper presents the results of a preliminary qualitative survey conducted in two French units and including 23 physicians and nurses. The answers indicate that withdrawal of treatments are part of their practices. Parents are never directly involved in the decision-making process. The decision to withdraw life sustaining treatments generate psychological distress among the caregivers. Nurses consider that they are more emotionally involved with the baby and the parents. They express concerns about painful treatments and life-prolonging therapies. Most respondents believe that an ethical committee would be of little help in the decision-making process and that the actual legislation should not be modified as it gives obligation for more in-depth consideration of each case.

Psychological consequences of having triplets: a 4-year follow-up study

OBJECTIVE

To assess the mental health of mothers of triplets and the quality of relationship with the children 4 years after delivery.

DESIGN

Prospective follow-up study from delivery, to 4 years. Assessments at home by a psychologist, using semistructured tape-recorded interviews.

SETTING

One maternity hospital in Paris, France.

PATIENT(S)

Eleven consecutive mothers having delivered triplets between October 1988 and February 1990. All except one had conceived after infertility treatment.

MAIN OUTCOME MEASURE(S)

Evaluation of the mothers' emotional well-being and level of depression measured by the CES-D Scale (Center for Epidemiologic Studies-Depression Scale). Opinion of the mothers about the quality of the relationship with the children.

RESULT(S)

All mothers reported emotional distress at 4 years, mainly fatigue and stress. Four mothers had a high score of depression and used psychotropic medication. The relationship with the children and difficulties in coping with their aggressive behavior and conflicts were the main reason for psychological distress. Difficulties had not decreased since the previous assessment at 2 years. Four mothers spontaneously expressed regrets about having triplets.

CONCLUSION(S)

Patients undergoing infertility treatments should receive adequate information about the long-term psychological "cost" of a triplet birth. Infertility treatments should be adapted in order to decrease the risk of triplet pregnancies.