4,009 research outputs found
Deep-water corals along the Norwegian contintental margin: Multidisciplinary studies on Sula Ridge, Traena Reef, Røst Reef, Floholmen and Sotbakken
Association between the squat lobster Gastroptychus formosus and cold-water corals in the North Atlantic
Although there are no previous descriptions of the habits of chirostylids in the North Atlantic, it is likely that species in the genera Uroptychus, Eumunida and Gastroptychus have close ecological ties with deep-sea corals since they have all been recorded in trawl samples containing corals from ∼200m depth. We analysed in situ distribution of Gastroptychus formosus and potential hosts using a ROV at a range of north-eastern Atlantic sites and found that this species forms a close association with deep-sea corals that resembles the chirostylid-anthozoan associations reported in shallow Indo-Pacific waters. We update the known distribution for G. formosus, confirming that it is an amphiatlantic species that occurs along the Mid-Atlantic Ridge at least as far south as the Azores and along continental margins from the Canary Islands to Scotland at depths of 600-1700m. The adults have very specific habitat preferences, being only found on gorgonian and antipatharian corals with a strong preference for Leiopathes sp. as a host. This highly restricted habitat preference is likely to render chirostylids vulnerable to the impacts of demersal fishing both directly, as by-catch, and indirectly through habitat loss. © 2010 Marine Biological Association of the United Kingdom
Complex -Glycans Influence the Spatial Arrangement of Voltage Gated Potassium Channels in Membranes of Neuronal-Derived Cells
The intrinsic electrical properties of a neuron depend on expression of voltage gated potassium (Kv) channel isoforms, as well as their distribution and density in the plasma membrane. Recently, we showed that N-glycosylation site occupancy of Kv3.1b modulated its placement in the cell body and neurites of a neuronal-derived cell line, B35 neuroblastoma cells. To extrapolate this mechanism to other N-glycosylated Kv channels, we evaluated the impact of N-glycosylation occupancy of Kv3.1a and Kv1.1 channels. Western blots revealed that wild type Kv3.1a and Kv1.1 α-subunits had complex and oligomannose N-glycans, respectively, and that abolishment of the N-glycosylation site(s) generated Kv proteins without N-glycans. Total internal reflection fluorescence microscopy images revealed that N-glycans of Kv3.1a contributed to its placement in the cell membrane while N-glycans had no effect on the distribution of Kv1.1. Based on particle analysis of EGFP-Kv proteins in the adhered membrane, glycosylated forms of Kv3.1a, Kv1.1, and Kv3.1b had differences in the number, size or density of Kv protein clusters in the cell membrane of neurites and cell body of B35 cells. Differences were also observed between the unglycosylated forms of the Kv proteins. Cell dissociation assays revealed that cell-cell adhesion was increased by the presence of complex N-glycans of Kv3.1a, like Kv3.1b, whereas cell adhesion was similar in the oligomannose and unglycosylated Kv1.1 subunit containing B35 cells. Our findings provide direct evidence that N-glycans of Kv3.1 splice variants contribute to the placement of these glycoproteins in the plasma membrane of neuronal-derived cells while those of Kv1.1 were absent. Further when the cell membrane distribution of the Kv channel was modified by N-glycans then the cell-cell adhesion properties were altered. Our study demonstrates that N-glycosylation of Kv3.1a, like Kv3.1b, provides a mechanism for the distribution of these proteins to the cell body and outgrowths and thereby can generate different voltage-dependent conductances in these membranes
Oligocene-Miocene drainage evolution of NW Borneo: Stratigraphy, sedimentology and provenance of Tatau-Nyalau province sediments
Clastic sediments of Oligocene to Lower Miocene age form a major thick and widespread sequence in the Tatau-Nyalau province of the north Sarawak Miri Zone. New light and heavy mineral data, U-Pb detrital zircon geochronology and biostratigraphy are used to identify the age, depositional environment, and potential provenance of sediments to reconstruct the drainage evolution of NW Borneo. Based on the biostratigraphic ages, depositional environments and provenance characteristics we modify previous stratigraphy and divide the Oligocene to Lower Miocene sequences into the Nyalau Formation (Biban Sandstone Member and Upper Nyalau Member), Kakus Unit, and Merit-Pila Formation. Two dominant source provinces were identified: the Malay-Thai Tin Belt which supplied sediments dominated by Permian-Triassic zircons, and the Schwaner Mountains of central Borneo which are identified by abundant Cretaceous zircons. Sediments either came directly, or were recycled from older sedimentary rocks, from these sources. The Sunda River deposited the Nyalau Formation during the Oligocene to Early Miocene with a dominant Malay-Thai Tin Belt source. The Merit-Pila Formation of the Sibu Zone was deposited contemporaneously by a proto-Rajang River that drained Central Borneo (recycling the Rajang Group and Schwaner granitoids). Between c. 17 Ma the Sunda River system terminated and sedimentation was dominated by the northward prograding proto-Rajang River delta, depositing the Kakus Unit in the Miri Zone. This drainage system was active until the Late Miocene, before further uplift of Borneo terminated most sedimentation in the onshore part of present-day Borneo
IPA14-G-298 The Biak Basin and its Setting in the Bird’s Head Region of West Papua
The Bird’s Head region of West Papua is dissected by several major strike-slip faults, namely the Sorong, Ransiki and Yapen faults. Although the age and current activity of these faults is disputed, it is generally accepted that they were initiated within the last 23 million years. Several sedimentary basins, including the Biak Basin, filled largely by Cenozoic (mainly Neogene) carbonates, are found in close proximity to these faults, indicating a potential genetic link between faulting and basin formation. The Biak Basin is situated between the islands of Biak and Yapen, north of Cenderawasih Bay. The basin fill consists of three sequences with bounding unconformities traceable across the wider Bird’s Head region. These sequences form a complete megasequence that records changes in relative sealevel driven by uplift and subsidence within the region. The lowermost sequence comprises island arc volcanics accreted to the northern New Guinea margin at the end of the Paleogene. The top is marked by a Lower Miocene angular unconformity that can be traced to basins in the Bintuni region to the west. The middle megasequence within the basin is composed of Lower Miocene platform carbonates possibly correlative with the Kais Limestone found in the Salawati Basin to the west. The final sequence is marked by an unconformity caused by diachronous regional subsidence across the northern Bird’s Head that led to the drowning of localised carbonate platforms, including the collapse of the Kais Platform, and the initiation of strike-slip faulting. The movement along these faults has led to the formation of many of the modern sedimentary basins in the region
The vertebrate phylotypic stage and an early bilaterian-related stage in mouse embryogenesis defined by genomic information
BACKGROUND: Embryos of taxonomically different vertebrates are thought to pass through a stage in which they resemble one another morphologically. This "vertebrate phylotypic stage" may represent the basic vertebrate body plan that was established in the common ancestor of vertebrates. However, much controversy remains about when the phylotypic stage appears, and whether it even exists. To overcome the limitations of studies based on morphological comparison, we explored a comprehensive quantitative method for defining the constrained stage using expressed sequence tag (EST) data, gene ontologies (GO), and available genomes of various animals. If strong developmental constraints occur during the phylotypic stage of vertebrate embryos, then genes conserved among vertebrates would be highly expressed at this stage. RESULTS: We established a novel method for evaluating the ancestral nature of mouse embryonic stages that does not depend on comparative morphology. The numerical "ancestor index" revealed that the mouse indeed has a highly conserved embryonic period at embryonic day 8.0–8.5, the time of appearance of the pharyngeal arch and somites. During this period, the mouse prominently expresses GO-determined developmental genes shared among vertebrates. Similar analyses revealed the existence of a bilaterian-related period, during which GO-determined developmental genes shared among bilaterians are markedly expressed at the cleavage-to-gastrulation period. The genes associated with the phylotypic stage identified by our method are essential in embryogenesis. CONCLUSION: Our results demonstrate that the mid-embryonic stage of the mouse is indeed highly constrained, supporting the existence of the phylotypic stage. Furthermore, this candidate stage is preceded by a putative bilaterian ancestor-related period. These results not only support the developmental hourglass model, but also highlight the hierarchical aspect of embryogenesis proposed by von Baer. Identification of conserved stages and tissues by this method in various animals would be a powerful tool to examine the phylotypic stage hypothesis, and to understand which kinds of developmental events and gene sets are evolutionarily constrained and how they limit the possible variations of animal basic body plans
Mitigating slipping-related mortality from purse seine fisheries for small pelagic fish: case studies from European Atlantic waters
The release of unwanted catches (UWC) from purse seines, while the catch is still in the water, is known as “slipping”. Once thought to be a benign process, compared to discarding UWC overboard from the fishing vessel, it is now recognised that “slipping” can lead to significant mortality in the released fish if done inappropriately. In this chapter, we examine purse seining and slipping operations, and discuss what drives slipping and potential mitigation measures to reduce slipping mortality. We use three examples of purse seine fisheries for small pelagic species in the North-east Atlantic; from Norway, Portugal and Spain. The ideal solution (identifying and avoiding UWC before the net is set) requires the development of tools to enable fishers to better characterise target schools in terms of key selection criteria, e.g., with respect to species, individual size and catch biomass. Such tools are being developed, based primarily on hydro-acoustic technology. However, some UWC in purse seine catches are inevitable, and operational improvements in slipping practices have been shown to significantly reduce stress and mortality in the released UWC. We conclude with a discussion on the challenges currently facing the implementation of the European Union (EU) Landing Obligation with regards to minimising slipping related mortality.info:eu-repo/semantics/publishedVersio
On the Dynamics of the Deployment of Renewable Energy Production Capacities
This chapter falls within the context of modeling the deployment of renewable en-ergy production capacities in the scope of the energy transition. This problem is addressed from an energy point of view, i.e. the deployment of technologies is seen as an energy investment under the constraint that an initial budget of non-renewable energy is provided. Using the Energy Return on Energy Investment (ERoEI) characteristics of technologies, we propose MODERN, a discrete-time formalization of the deployment of renewable energy production capacities. Be-sides showing the influence of the ERoEI parameter, the model also underlines the potential benefits of designing control strategies for optimizing the deployment of production capacities, and the necessity to increase energy efficiency.Peer reviewe
Characterisation and induction of tissue-resident gamma delta T-cells to target hepatocellular carcinoma
Immunotherapy is now the standard of care for advanced hepatocellular carcinoma (HCC), yet many patients fail to respond. A major unmet goal is the boosting of T-cells with both strong HCC reactivity and the protective advantages of tissue-resident memory T-cells (TRM). Here, we show that higher intratumoural frequencies of γδ T-cells, which have potential for HLA-unrestricted tumour reactivity, associate with enhanced HCC patient survival. We demonstrate that γδ T-cells exhibit bona fide tissue-residency in human liver and HCC, with γδTRM showing no egress from hepatic vasculature, persistence for >10 years and superior anti-tumour cytokine production. The Vγ9Vδ2 T-cell subset is selectively depleted in HCC but can efficiently target HCC cell lines sensitised to accumulate isopentenyl-pyrophosphate by the aminobisphosphonate Zoledronic acid. Aminobisphosphonate-based expansion of peripheral Vγ9Vδ2 T-cells recapitulates a TRM phenotype and boosts cytotoxic potential. Thus, our data suggest more universally effective HCC immunotherapy may be achieved by combining aminobisphosphonates to induce Vγ9Vδ2TRM capable of replenishing the depleted pool, with additional intratumoural delivery to sensitise HCC to Vγ9Vδ2TRM-based targeting
Glycan Structures Contain Information for the Spatial Arrangement of Glycoproteins in the Plasma Membrane
Glycoconjugates at the cell surface are crucial for cells to communicate with each other and the extracellular microenvironment. While it is generally accepted that glycans are vectorial biopolymers, their information content is unclear. This report provides evidence that distinct N-glycan structures influence the spatial arrangement of two integral membrane glycoproteins, Kv3.1 and E-cadherin, at the adherent membrane which in turn alter cellular properties. Distinct N-glycan structures were generated by heterologous expression of these glycoproteins in parental and glycosylation mutant Chinese hamster ovary cell lines. Unlike the N-linked glycans, the O-linked glycans of the mutant cell lines are similar to those of the parental cell line. Western and lectin blots of total membranes and GFP immunopurified samples, combined with glycosidase digestion reactions, were employed to verify the glycoproteins had predominantly complex, oligomannose, and bisecting type N-glycans from Pro(-)5, Lec1, and Lec10B cell lines, respectively. Based on total internal reflection fluorescence and differential interference contrast microscopy techniques, and cellular assays of live parental and glycosylation mutant CHO cells, we propose that glycoproteins with complex, oligomannose or bisecting type N-glycans relay information for localization of glycoproteins to various regions of the plasma membrane in both a glycan-specific and protein-specific manner, and furthermore cell-cell interactions are required for deciphering much of this information. These distinct spatial arrangements also impact cell adhesion and migration. Our findings provide direct evidence that N-glycan structures of glycoproteins contribute significantly to the information content of cells
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