Blood dynamics of mercury and selenium in northern elephant seals during the lactation period

The effects of reproduction and maternal investment (i.e., milk transfer) on trace element levels remain poorly understood in marine mammals. We examined the blood dynamics of mercury (Hg) and selenium (Se) during lactation in the northern elephant seal (Mirounga angustirostris), a top predator from the North Pacific Ocean. Total Hg and Se levels were measured in whole blood and milk of 10 mother-pup pairs on days 5 and 22 of lactation. Both Hg and Se were transferred to offspring through the milk. Results suggested that the maternal transfer of Se was prominent during lactation, whereas the Hg transfer was larger during gestation. The lactation period affected Hg and Se levels in the blood of elephant seal mothers and pups. Physiological processes and their relationship to body condition should be considered carefully when interpreting trace element levels in the framework of biomonitoring.Peer reviewe

Changes in stable isotope compositions during fasting in phocid seals

This study was supported by NSF grant #0213095 and by FRFC grant #2.4502.07 (F.R.S.-FNRS).Rationale:  The grey seal, Halichoerus grypus (GS), and the northern elephant seal, Mirounga angustirostris (NES), come ashore for reproduction. This period involves intense physiological processes such as lactation in females and a developmental post‐weaning fast in juveniles. Previous studies have shown that δ13C and δ15N values are affected by starvation, but the precise effects of fasting associated to lactation and post‐weaning fast in seals remain poorly understood. Methods:  To examine the effect of lactation and post‐weaning fast on stable isotope ratios in GS and NES, blood and hair were sampled from twenty‐one GS mother‐pup pairs on the Isle of May and on twenty‐two weaned NES pups at Año Nuevo State Reserve during their respective breeding seasons. Milk samples were also collected from GS mothers. Stable isotope measurements were performed with an isotope ratio mass spectrometer coupled to an N‐C elemental analyser. Results:  Changes in stable isotope ratios in blood components during fasting were similar and weak between GS and NES mothers especially in blood cells (GS: Δ15N = 0.05‰, Δ13C = 0.02‰; NES: Δ15N = 0.1‰, Δ13C = 0.1‰). GS showed a 15N discrimination factor between maternal and pup blood cells and milk, but not for 13C. The strongest relationship between the isotopic compositions of the mother and the pup was observed in the blood cells. Conclusion:  Isotopic consequences of lactation, fasting, and growth seem limited in NES and GS, especially in medium‐term integrator tissues of feeding activity such as blood cells. Stable isotope ratios in the blood of pups and mothers are correlated. We observed a subtle mother‐to‐pup fractionation factor. Our results suggest that pup blood cells are mostly relevant for exploring the ecology of female seals.PostprintPeer reviewe

Grapevine rootstocks shape underground bacterial microbiome and networking but not potential functionality

BackgroundThe plant compartments of Vitis vinifera, including the rhizosphere, rhizoplane, root endosphere, phyllosphere and carposphere, provide unique niches that drive specific bacterial microbiome associations. The majority of phyllosphere endophytes originate from the soil and migrate up to the aerial compartments through the root endosphere. Thus, the soil and root endosphere partially define the aerial endosphere in the leaves and berries, contributing to the terroir of the fruit. However, V. vinifera cultivars are invariably grafted onto the rootstocks of other Vitis species and hybrids. It has been hypothesized that the plant species determines the microbiome of the root endosphere and, as a consequence, the aerial endosphere. In this work, we test the first part of this hypothesis. We investigate whether different rootstocks influence the bacteria selected from the surrounding soil, affecting the bacterial diversity and potential functionality of the rhizosphere and root endosphere.MethodsBacterial microbiomes from both the root tissues and the rhizosphere of Barbera cultivars, both ungrafted and grafted on four different rootstocks, cultivated in the same soil from the same vineyard, were characterized by 16S rRNA high-throughput sequencing. To assess the influence of the root genotype on the bacterial communities’ recruitment in the root system, (i) the phylogenetic diversity coupled with the predicted functional profiles and (ii) the co-occurrence bacterial networks were determined. Cultivation-dependent approaches were used to reveal the plant-growth promoting (PGP) potential associated with the grafted and ungrafted root systems.ResultsRichness, diversity and bacterial community networking in the root compartments were significantly influenced by the rootstocks. Complementary to a shared bacterial microbiome, different subsets of soil bacteria, including those endowed with PGP traits, were selected by the root system compartments of different rootstocks. The interaction between the root compartments and the rootstock exerted a unique selective pressure that enhanced niche differentiation, but rootstock-specific bacterial communities were still recruited with conserved PGP traits.ConclusionWhile the rootstock significantly influences the taxonomy, structure and network properties of the bacterial community in grapevine roots, a homeostatic effect on the distribution of the predicted and potential functional PGP traits was found

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

Contains fulltext : 172380.pdf (publisher's version ) (Open Access

Maternal transfer of mercury to offspring in phocids

Marine mammals may display high mercury (Hg) levels in their tissues, which raises the question of the importance of toxic metal transfer from mother to offspring. Indeed, Hg could be transferred from mothers to fetuses via the placenta and to suckling pups via the milk, potentially affecting them during their most sensitive periods of development. Some lactating female phocids fast during the suckling period. This fasting period involves not only an important mobilization of energy reserves, but also mobilization of potentially associated contaminants. We studied and compared maternal transfer of Hg to offspring in two phocid species: the northern elephant seal (Mirounga angustirostris) from the Californian coast and the grey seal (Halichoerus grypus) from the Isle of May in Scotland. Total mercury concentrations (THg) were measured in whole blood and maternal milk of 20 mother-pup pairs of each species in early and late lactation. Methylmercury (MeHg) levels were also measured in the blood and milk of grey seals. Results indicated that Hg passed from the maternal tissue into the phocid milk. Milk showed a range of THg levels from 15 to 60 ppb (ng.g-1-wet-weight). From the first days after birth, pups displayed relatively high blood Hg levels suggesting that a Hg transfer through placenta occurred. Blood Hg levels in mothers and pups also varied significantly throughout lactation. While maternal levels doubled, pup levels were reduced by half between the beginning and the end of lactation. Remobilization of proteins and lipids during fasting and milk production in mothers might lead to a release of Hg in blood and therefore increase the levels in late lactation. On the contrary, Hg would be progressively stored in pup organs during their development. Decreasing Hg levels in pups also suggest that the Hg intake via the milk might be lower than that via the placenta. This study highlights a transplacental and transmammary transfer of Hg in both phocid populations. However, further toxicology studies are needed to help understand the potential impact of this Hg transfer. Results also showed that physiological processes such as lactation and/or fasting can modify Hg levels in the blood of mothers and pups. Therefore, such processes and body condition should be considered carefully when interpreting Hg levels in the framework of biomonitoring

Effect of arterial pressure measurement location on pulse contour stroke volume estimation, during a rapid change in hemodynamic state

Continuous cardiac output monitors are becoming more common in clinical settings to assess cardiac performance. Pulse contour analysis is a common method employed by commercial devices to estimate patient hemodynamics from a pressure waveform and relate it to volume. The main issue with current devices, is they can perform poorly during and after a significant hemodynamic event. An existing pulse contour analysis method, under ideal experimental conditions, demonstrated the ability to track changes in stroke volume (SV) using a measure of pulse wave velocity (PWV). In this study, the existing method's ability to estimate SV was tested during vena cava occlusions (VCO), a worst case, rapid transient hemodynamic change. Additionally, the method's sensitivity to the location of the arterial pressure waveform measurement was also assessed, by comparing SV estimates from aortic and iliac pressures, to SV measured by admittance catheter in the ventricle. Results show the model accurately tracks changes in SV as a result of the occlusion, a significant improvement over current commercially available devices. Bland-Altman analysis showed no significant improvement in SV estimation when using aortic pressure compared to the iliac pressure waveform, with mean bias of -2.11ml and 0.13ml, respectively. This is a desirable result, as more distal arterial pressure measurement locations increase the clinical feasibility of the method. © 201

Effects of polychlorobiphenyls, polybromodiphenylethers, organochlorine pesticides and their metabolites on vitamin A status in lactating grey seals

Polychlorobiphenyls (PCBs), polybromodiphenylethers (PBDEs) and organochlorine pesticides (OCPs) such as dichlorodiphenyltrichloroethane (DDT) and hexachlorobenzene (HCB) are considered to be endocrine disruptors in laboratory and wild animals. This study investigated whether these compounds and their hydroxylated metabolites (HO-PCBs and HO-PBDEs) may affect the homeostasis of vitamin A, a dietary hormone, in the blubber and serum of twenty lactating grey seals sampled at early and late lactation on the Isle of May, Scotland. The effect of naturally produced compounds such as the methoxylated (MeO)-PBDEs was also examined. Vitamin A levels in inner blubber (37 ± 9 µg/g wet weight (ww) and 92 ± 32 µg/g ww at early and late lactation, respectively) and serum (408 ± 143 ng/ml and 390 ± 98 ng/ml at early and late lactation, respectively) appeared to be positively related to ΣPCBs, ΣPBDEs and several individual PCB and PBDE congeners in inner blubber and serum. These findings may suggest an enhanced mobilisation of hepatic retinoid stores and a redistribution in the blubber, a storage site for vitamin A in marine mammals, before the onset of lactation. We also reported that serum concentrations of ΣHO-PCBs and 4-OH-CB107 tended to increase circulating vitamin A levels. Although the direction of the relationships may sometimes differ from those reported in the literature, our results are in agreement with previous findings highlighting a disruption of vitamin A homeostasis in the blubber and bloodstream following exposure to environmental pollutants. Previous studies have shown an interesting parallelism between the mobilisation and transfer of vitamin A and those of PCBs in lactating grey seals, contrary to other lipophilic molecules such as vitamin E (Debier et al. 2004; Vanden Berghe et al. 2010). The fact that vitamin A and PCBs appeared to share common mechanisms during this particular physiological state in grey seals (lactation coupled to a total fasting) may also play a role in the different relationships observed between vitamin A and lipophilic pollutants

A transcriptomic comparison of late-ripening Cabernet Sauvignon berry skins from Bordeaux and Reno

Oral presentation. 12th International Conference on Grapevine Breeding and Genetics, 2018 Jul 15-20, Bordeau

Lepidocrocite-like ferrititanate nanosheets and their full exfoliation with quaternary ammonium compounds

Efficient methods for the synthesis of layered structure nanomaterials (nanosheets), their complete exfoliation (delamination) into the layers of atomic thickness and design of organic-inorganic nanohybrids present important stages toward development of improved polymer-based nanocomposites and pillared heterostructures with potential application in purification technologies such as photocatalysis. A rapid and efficient exfoliation process of protonated layered ferrititanates with lepidocrocite-like structure and formation of organic-inorganic nanohybrids is performed starting from the nanosheets composed of only a few host layers and nanometric lateral dimensions using quaternary ammonium compounds. These nanosheets are initially synthesized from a highly abundant precursor through an alkaline hydrothermal route. We demonstrated that climethyldioctadecylammonium cations strongly interact with the exfoliated single host layers (075 nm thick) providing thermal stability (-500 "C) to the as-prepared organic-inorganic nanohybrid over the temperature range commonly applied for the processing of thermoplastic nanocomposites. (C) 2015 Elsevier Ltd. All rights reserved