47 research outputs found
Developing Tools to Evaluate Spawning & Fertilization Dynamics of the Giant Sea Scallop β Phase II: Field Trials in Experimental Populations
Objective 1 β Sperm advection-diffusion model: Develop a two-dimensional spatial model to predict the concentration o f sperm and effective range of fertilization in a sperm plume at varying distances from a source population of spawning males under scenarios of synchronous and asynchronous spawning.
Objective 2 β Fertilization assays in field populations: Conduct a time series of fertilization assays over experimental populations of scallops to (a) further develop the methodology to assess ambient sperm loads in scallop populations over the course of the spawning season, (b) compare model predictions about spatial patterns of sperm concentration and fertilization generated in Objective 1 to field observations on experimental populations, (c) determine the influence of differences in the sperm plume arising from two experimental populations spanning a ten-fold difference in male density, and (d) conduct laboratory flume experiments to evaluate potential biases introduced by Nitex egg baskets to estimates of absolute and relative rates of fertilization
Different Early Post-Settlement Strategies Between American Lobsters Homarus Americanus and Rock Crabs Cancer Irroratus in the Gulf of Maine
The abundance of many invertebrates with planktonic larval stages can be determined shortly after they reach the benthos. In this study, we quantified patterns of abundance and habitat utilization of early benthic phases of the American lobster Homarus americanus and the rock crab Cancer irroratus. These 2 decapods are among the most common and abundant macroinvertebrates in coastal zones of the Gulf of Maine, with similar densities of larger individuals. Settlement and early postsettlement survival indicate that lobsters are highly substrate-specific early in life, settling predominantly in cobble beds. Crabs appear to be less selective, setting both in cobble and sand. Cumulative settlement of crabs, inferred from weekly censuses over the summer, was an order of magnitude greater than that of lobsters over the same time period. However, only crabs showed significant postsettlement losses. Although the identity of specific predators is unknown, predator exclusion experiments and placement of vacant uninhabited nursery habitat suggested that post-settlement mortality rather than emigration was responsible for these losses. The selective habitat-seeking behavior and lower post-settlement mortality of lobsters is consistent with their lower fecundity and later onset of reproductive maturity. The patterns observed for crabs, however, suggest a different strategy which is more in accordance with their higher fecundity and earlier onset of maturity. It is possible that lower fecundity but greater per-egg investment, along with strict habitat selection at settlement and lower post-settlement mortality, allows adult lobster populations to equal adult populations of crabs. This occurs despite crabs being more fecund and less habitat-selective settlers but sustaining higher postsettlement mortality
CKI isoforms Ξ± and Ξ΅ regulate StarβPAP target messages by controlling StarβPAP poly(A) polymerase activity and phosphoinositide stimulation
StarβPAP is a non-canonical, nuclear poly(A) polymerase (PAP) that is regulated by the lipid signaling molecule phosphatidylinositol 4,5 bisphosphate (PI4,5P2), and is required for the expression of a select set of mRNAs. It was previously reported that a PI4,5P2 sensitive CKI isoform, CKIΞ± associates with and phosphorylates StarβPAP in its catalytic domain. Here, we show that the oxidative stress-induced by tBHQ treatment stimulates the CKI mediated phosphorylation of StarβPAP, which is critical for both its polyadenylation activity and stimulation by PI4,5P2. CKI activity was required for the expression and efficient 3β²-end processing of its target mRNAs in vivo as well as the polyadenylation activity of StarβPAP in vitro. Specific CKI activity inhibitors (IC261 and CKI7) block in vivo StarβPAP activity, but the knockdown of CKIΞ± did not equivalently inhibit the expression of StarβPAP targets. We show that in addition to CKIΞ±, StarβPAP associates with another CKI isoform, CKIΞ΅ in the StarβPAP complex that phosphorylates StarβPAP and complements the loss of CKIΞ±. Knockdown of both CKI isoforms (Ξ± and Ξ΅) resulted in the loss of expression and the 3β²-end processing of StarβPAP targets similar to the CKI activity inhibitors. Our results demonstrate that CKI isoforms Ξ± and Ξ΅ modulate StarβPAP activity and regulates StarβPAP target messages
Ocean and coastal acidification off New England and Nova Scotia
Author Posting. Β© The Oceanography Society, 2015. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 28, no. 2 (2015): 182-197, doi:10.5670/oceanog.2015.41.New England coastal and adjacent Nova Scotia shelf waters have a reduced buffering capacity because of significant freshwater input, making the regionβs waters potentially more vulnerable to coastal acidification. Nutrient loading and heavy precipitation events further acidify the regionβs poorly buffered coastal waters. Despite the apparent vulnerability of these waters, and fisheriesβ and maricultureβs significant dependence on calcifying species, the community lacks the ability to confidently predict how the regionβs ecosystems will respond to continued ocean and coastal acidification. Here, we discuss ocean and coastal acidification processes specific to New England coastal and Nova Scotia shelf waters and review current understanding of the biological consequences most relevant to the region. We also identify key research and monitoring needs to be addressed and highlight existing capacities that should be leveraged to advance a regional understanding of ocean and coastal acidification.This project was supported in part by an appointment
to the Internship/Research Participation Program
at the Office of Water, US Environmental Protection
Agency (EPA), administered by the Oak Ridge Institute
for Science and Education through an interagency
agreement between the US Department of Energy
and the EPA. JS acknowledges support from NASA
grant from NNX14AL84G NASA-CCS
New high statistics measurement of decay form factors and scattering phase shifts
We report results from a new measurement of the decay by the NA48/2 collaboration at the CERN SPS, based on a partial sample of more than 670000 decays in both charged modes collected in 2003. The form factors of the hadronic current (F, G, H) and phase difference () have been measured in ten independent bins of the mass spectrum to investigate the variation. A sizeable acceptance at large mass, a low background and a very good resolution contribute to an improved experimental accuracy, a factor two better than in the previous measurement, when extracting the scattering lengths and . Under the assumption of isospin symmetry and using numerical solutions of the Roy equations, the following values are obtained in the plane (. The presence of potentially large isospin effects is also considered and will allow comparison with precise predictions from Chiral Perturbation Theory
Search for direct CP violating charge asymmetries in and decays
A measurement of the direct CP violating charge asymmetries of the Dalitz
plot linear slopes in and
decays by the NA48/2 experiment at CERN SPS is
presented. A new technique of asymmetry measurement involving simultaneous
and beams and a large data sample collected allowed a result of an
unprecedented precision. The charge asymmetries were measured to be
with
decays, and with
decays. The precision of the
results is limited mainly by the size of the data sample.Comment: 29 pages, 9 figures. An updated version accepted by the EPJ
Biodiversity of the Deep-Sea Continental Margin Bordering the Gulf of Maine (NW Atlantic): Relationships among Sub-Regions and to Shelf Systems
Background: In contrast to the well-studied continental shelf region of the Gulf of Maine, fundamental questions regarding
the diversity, distribution, and abundance of species living in deep-sea habitats along the adjacent continental margin
remain unanswered. Lack of such knowledge precludes a greater understanding of the Gulf of Maine ecosystem and limits
development of alternatives for conservation and management.
Methodology/Principal Findings: We use data from the published literature, unpublished studies, museum records and
online sources, to: (1) assess the current state of knowledge of species diversity in the deep-sea habitats adjacent to the Gulf
of Maine (39β43uN, 63β71uW, 150β3000 m depth); (2) compare patterns of taxonomic diversity and distribution of
megafaunal and macrofaunal species among six distinct sub-regions and to the continental shelf; and (3) estimate the
amount of unknown diversity in the region. Known diversity for the deep-sea region is 1,671 species; most are narrowly
distributed and known to occur within only one sub-region. The number of species varies by sub-region and is directly
related to sampling effort occurring within each. Fishes, corals, decapod crustaceans, molluscs, and echinoderms are
relatively well known, while most other taxonomic groups are poorly known. Taxonomic diversity decreases with increasing
distance from the continental shelf and with changes in benthic topography. Low similarity in faunal composition suggests
the deep-sea region harbours faunal communities distinct from those of the continental shelf. Non-parametric estimators of
species richness suggest a minimum of 50% of the deep-sea species inventory remains to be discovered.
Conclusions/Significance: The current state of knowledge of biodiversity in this deep-sea region is rudimentary. Our ability
to answer questions is hampered by a lack of sufficient data for many taxonomic groups, which is constrained by sampling
biases, life-history characteristics of target species, and the lack of trained taxonomists
Developmental Patterns of Doublecortin Expression and White Matter Neuron Density in the Postnatal Primate Prefrontal Cortex and Schizophrenia
Postnatal neurogenesis occurs in the subventricular zone and dentate gyrus, and evidence suggests that new neurons may be present in additional regions of the mature primate brain, including the prefrontal cortex (PFC). Addition of new neurons to the PFC implies local generation of neurons or migration from areas such as the subventricular zone. We examined the putative contribution of new, migrating neurons to postnatal cortical development by determining the density of neurons in white matter subjacent to the cortex and measuring expression of doublecortin (DCX), a microtubule-associated protein involved in neuronal migration, in humans and rhesus macaques. We found a striking decline in DCX expression (human and macaque) and density of white matter neurons (humans) during infancy, consistent with the arrival of new neurons in the early postnatal cortex. Considering the expansion of the brain during this time, the decline in white matter neuron density does not necessarily indicate reduced total numbers of white matter neurons in early postnatal life. Furthermore, numerous cells in the white matter and deep grey matter were positive for the migration-associated glycoprotein polysialiated-neuronal cell adhesion molecule and GAD65/67, suggesting that immature migrating neurons in the adult may be GABAergic. We also examined DCX mRNA in the PFC of adult schizophrenia patients (nβ=β37) and matched controls (nβ=β37) and did not find any difference in DCX mRNA expression. However, we report a negative correlation between DCX mRNA expression and white matter neuron density in adult schizophrenia patients, in contrast to a positive correlation in human development where DCX mRNA and white matter neuron density are higher earlier in life. Accumulation of neurons in the white matter in schizophrenia would be congruent with a negative correlation between DCX mRNA and white matter neuron density and support the hypothesis of a migration deficit in schizophrenia