Munc18-dependent and -independent clustering of syntaxin in the plasma membrane of cultured endocrine cells

Syntaxin helps in catalyzing membrane fusion during exocytosis. It also forms clusters in the plasma membrane, where both its transmembrane and SNARE domains are thought to homo-oligomerize. To study syntaxin clustering in live PC12 cells, we labeled granules with neuropeptide-Y-mCherry and syntaxin clusters with syntaxin-1a green fluorescent protein (GFP). Abundant clusters appeared under total internal reflection (TIRF) illumination, and some of them associated with granules (“on-granule clusters”). Syntaxin-1a-GFP or its mutants were expressed at low levels and competed with an excess of endogenous syntaxin for inclusion into clusters. On-granule inclusion was diminished by mutations known to inhibit binding to Munc18-1 in vitro. Knock-down of Munc18-1 revealed Munc18-dependent and -independent on-granule clustering. Clustering was inhibited by mutations expected to break salt bridges between syntaxin’s Hb and SNARE domains and was rescued by additional mutations expected to restore them. Most likely, syntaxin is in a closed conformation when it clusters on granules, and its SNARE and Hb domains approach to within atomic distances. Pairwise replacements of Munc18-contacting residues with alanines had only modest effects, except that the pair R114A/I115A essentially abolished on-granule clustering. In summary, an on-granule cluster arises from the specific interaction between a granule and a dense cluster of syntaxin-Munc18-1 complexes. Off-granule clusters, by contrast, were resistant to even the strongest mutations we tried and required neither Munc18-1 nor the presence of a SNARE domain. They may well form through the nonstoichiometric interactions with membrane lipids that others have observed in cell-free systems.

Decoherent Excitation of Transverse Free Currents in Dielectric Liquids via Inter-Molecular Interactions

We present a theoretical model for a class of optical scattering experiments in which short-duration, linearly-polarized electromagnetic pulses scatter off dielectric liquids. The pattern of scattering, particularly in the transverse direction, indicates that significant free currents are generated in the direction orthogonal to the polarization of the incident light. Modelling the target as a dense cluster of two-level systems, we show that transverse free currents are produced by short duration, electric-dipole interactions between proximate molecules, and result in scattering patterns similar to those observed in the experiments. Calculations provide a rationale for why these scattering patterns are not observed in the same molecules at lower densities or with lower field intensities. These features make this model a relevant alternative to proposed transverse optical magnetism theories.

Ancient Thebes

The principal city of Boiotia, Thebes exerted influence and at times control over the great expanse of Central Greece, from the South Euboean Gulf at east to the Gulf of Corinth at west. Lying north of the massif of Parnes (and its most famous spur, Cithaeron), Thebes bestrides the western reaches of a low mountain range running east toward Tanagra and governs access to the flatlands along the Asopus river to the south, to the plains stretching north and east toward Helicon and the Copais (the Teneric plain), and to the level expanses extending west toward the sea south of the Messapion-Ptoon line (the Aonian plain). Thebes itself sits on a dense cluster of hills. One such hill, the Cadmea, is the age-old acropolis. The river Dirce runs just west of the Cadmea. Two rivers lie east: the Strophia (or Chrysoroas), which runs immediately next to the Cadmea, and, further east, the Ismenos. Thebes has a grand mythic history. Founded by the Phoenician Cadmus (in one tradition) while in search of his sister, Europa, the city is the birthplace of two sons of Zeus, Dionysus and Heracles, and an imposing mortal line which includes Oedipus. Impressive Bronze Age remains have long lent intrigue to these traditions. Thebes had regional and extra-regional aspirations by the 6th century, with mythic, epigraphic, and historical references indicating rivalry with neighboring Boiotian communities as well as Athens and Thessaly. Famous for medizing during the Persian Wars, Thebes likely acted within a Boiotian collective by the middle of the 5th century. Thebans joined the Peloponnesian cause in the Peloponnesian War but thereafter came into running conflict with Sparta. The city expelled an imposed Spartan garrison in 379, and the leaders Epaminondas and Pelopidas brought forth a period of expansive Theban hegemony after Leuctra (371). Following the shared defeat at Chaeronea in 338—where Thebes’ renowned Sacred Band came to ruin—the city endured a Macedonian garrison. Destroyed by Alexander in 335 for rebellion, Thebes was rebuilt in the time of Cassander (316). The city functioned as a member of a Boiotian collective subsequently, but Sulla stripped its territory in 86 for Thebes’ backing of Mithridates. Thebes sank to relative insignificance thereafter and did not rise to prominence again until Byzantine times. A prosperous international city after Justinian and into the Middle Ages, Thebes’ importance receded under Ottoman domination.

Vulnerable Marine Ecosystems, Communities, and Indicator Species: Confusing Concepts for Conservation of Seamounts

The concept of “vulnerable marine ecosystem” (VME) was included in United Nations (UN) General Assembly Resolution 61/105 as part of an international effort to minimize the effects of seafloor fisheries on the high seas. However, defining a VME was left to be developed by technical guidance to the UN Food and Agricultural Organization. In that venue certain categories of organisms were deemed to be indicator species, suggesting that areas with those species would be considered VMEs with subsequent management measures implemented to conserve those ecosystem attributes. We note that on seamounts VME indicator species can be distributed widely, in dense clusters or sparsely. A dense cluster, for example, of scleractinian corals or sponges, is most often referred to as a VME, but we argue that any such dense cluster is not an ecosystem, rather it is a community, likely one of many that make up the ecosystem. Other communities on the seamount that are not part of that dense cluster could include many small species (some yet to be discovered) who are also part of the ecosystem because they are part of the web of interactions and flow of materials/energy on the seamount. We also suggest that a seamount ecosystem might extend over several or many seamounts in a biogeographic area. We conclude that the term “ecosystem” in the VME concept outlined by the United Nations needs to be re-evaluated from a classical ecological perspective leading to spatial management approaches that better address ecologically relevant space and time scales.

Hydroacoustic observations of Two Contrasted Seismic Swarms along the Southwest Indian Ridge in 2018

<p><span><span>In 2018, two earthquake swarms occurred along segments of the ultra-slow Southwest Indian Ridge (spreading rate: 14-15 mm/a). The first swarm is located at the spreading-ridge intersection with the Atlantis Fracture Zone and comprises 9 Mw > 5.0 events (GCMT catalogue) and about 227 lower magnitude events (ISC catalogue), spanning over </span></span><span> </span><span><span>9</span></span><span><span> days (July </span></span><span><span>10</span></span><span><span>-1</span></span><span><span>8</span></span><span><span>).</span></span><span><span> The second crisis is more of a cluster of events focusing near a discontinuity, 220km away from the Indian Triple Junction and comprises 6 Mw > 5 events (GCMT) and 87 lower magnitude events (ISC catalogue), spanning over 30 days (September 2</span></span><span><span>8</span></span><span><span> to October 27). All focal mechanisms (GCMT) indicate normal faulting for both swarms. These two swarms are examined using hydroacoustic records from the OHASISBIO network with 7 to 9 </span></span><span><span>autonomous h</span></span><span><span>ydrophones moored on either side of Southwest Indian Ridge. </span></span></p><p><span><span>The first swarm initiates with a Mw=4.9 event (July 10 2018, 03h55) which triggers numerous events with an average of ~250 events per day for the first three days (July 10</span></span><span><sup></sup></span><span><span>to 12), propagating in the NE direction. After this, the seismic activity ceases down along with a sparse distribution of events until another </span></span><span><span>burst of activity initiating</span></span><span><span> after July 15, last</span></span><span><span>ing</span></span><span><span> for 3 days and comprising of several high intensity events. Overall, this swarm includes ~1100 hydroacoustic events spanning over 13 days.</span></span></p><p><span><span>The second swarm, further east, starts with two events, Mw=5.5 and 5.6 (Sept. 28 2018, 6h21 and 7h06), followed by a few discrete events. After 3 days, a dense cluster of events initiates with a Mw=5.4 event (October 1st, 18h16) and lasts for 7 days (~415 events per day) and decreases till the end of October. Two additional sub-swarms occur on October 1st and on October 6, both propagating towards the NE. Several other high intensity events occur October 10, after which seismic activity propagates towards the SE </span></span><span><span>and fades away until October 27. </span></span><span><span>Overall, this swarm includes ~5000 hydroacoustic events spanning over 33 days.</span></span></p><p><span>The number of events per day is thus larger for the second swarm than for the first one. Also, event source levels are in average smaller in the second crisis than in the first one. Further analyses of these characteristics, along with the different geographical and time distribution of the ~6000 acoustic events (vs ~300 events in the land-based catalogues), provide insights on the onset and on the tectonic or magmatic origin of these two contrasting swarms. </span></p>

Study and application of wellbore trajectory optimization for dense cluster wells

In the middle and late stage of oilfield exploration and development, the difficulties such as land acquisition on the surface, high density of underground well pattern and high development cost are serious. Dense cluster Wells are mainly way to development mode transformation and quality and efficiency improvement. Combined with the practice of dense cluster well in Dagang Oilfield, the paper detailed analyzes the difficulties faced by the design of dense cluster well drilling engineering, which including well pattern arrangement, wellbore trajectory optimization, wells anti-collision, all of those are beneficial to realize benefit drilling development. The applications show that this technology has a significant effect on improving wellsite utilization rate, shortening drilling cycle and reducing drilling cost in Dagang oilfield, and has a very important reference and popularization significance in similar oilfield development.

HYDROGEN PERMEABILITY OF AMORPHOUS, NANO- AND CRYSTALLINE ALLOYS BASED ON IRON AND NICKEL

Исследована кинетика проницаемости и диффузии водорода в гидрированых мембранных сплавах на основе Fe и Ni, обладающих функциональными характеристиками, конструкционной прочностью и термостабильностью, и являющихся многообещающей альтернативой дорогим палладиевым сплавам. Изучены прочностные характеристики, термостабильность и устойчивость к водородному охрупчиванию. Рассмотрены механизмы структурирования, диффузии и проницаемости водорода в кристаллическом, аморфном, нанокристаллическом состояниях. Для мембранных сплавов особо важным аспектом является сочетание в открытых структур (аморфных и ОЦК), в то время как для аккумулирования водорода, помимо каналов транспорта (диффузии и проницаемости) также необходимы и высокоплотные интерметаллидные кластеры. Отмечено, что при длительной эксплуатации вследствие возникновения плотных кластерных конфигураций среднего упорядочения, сокращающих диффузионные каналы, начинается снижение через них транспорта водорода. The kinetics of hydrogen permeability and diffusion in hydrogenated membrane alloys based on Fe and Ni have been investigated, which have functional characteristics, structural strength and thermal stability, and are a promising alternative to expensive palladium alloys. The strength characteristics, thermal stability and resistance to hydrogen embrittlement have been studied. The mechanisms of structuring, diffusion and permeability of hydrogen in crystalline, amorphous, nanocrystalline states are considered. For membrane alloys, a particularly important aspect is the combination in open structures (amorphous and bcc), while for hydrogen accumulation, in addition to transport channels (diffusion and permeability), high-density intermetallic clusters are also required. It is noted that, during long-term operation, due to the appearance of dense cluster configurations of intermediate ordering, which shorten the diffusion channels, the transport of hydrogen through them begins to decrease.

Aspects of the palaeontology of Salthill Quarry, Clitheroe, Lancashire (Mississippian), NW England

Salthill Quarry, Clitheroe, Lancashire (Mississippian, early Visean, Chadian) is a Site of Special Scientific Interest on the basis of its diverse fauna of invertebrates preserved in a Waulsortian mud mound setting. Important new specimens are described from the limestones and thin mudstones of the Hodder Mudstone Formation, on the southern margin of the quarry. A rare echinoid, archaeocidarid? gen. et sp. indet., is incomplete, but unusually retains the original curvature of the test. A columnal of Bystrowicrinus (col.) westheadi Donovan was derived from a radicular runner and has a dense cluster of radice scars on one side only. The columnal had a wedge-like section, thus suggesting a curvature of the stem. A cluster of solitary rugose corals on the base of a limestone bed includes at least two geniculated specimens in life position, the calice raised above the base of the bed. This is more likely to be due to burial in situ than a current accumulation. Ostiocavichnus Bohatý et al. is not an ichnotaxon, but a palaeopathology identified as a swollen crinoid pluricolumnal; broadly analogous structures are identified in fossil decapod crustaceans.

Direct Parabrachial–Cortical Connectivity

The parabrachial nucleus (PB) in the upper brain stem tegmentum includes several neuronal subpopulations with a wide variety of connections and functions. A subpopulation of PB neurons projects axons directly to the cerebral cortex, and limbic areas of the cerebral cortex send a return projection directly to the PB. We used retrograde and Cre-dependent anterograde tracing to identify genetic markers and characterize this PB–cortical interconnectivity in mice. Cortical projections originate from glutamatergic PB neurons that contain Lmx1b (81%), estrogen receptor alpha (26%), and Satb2 (20%), plus mRNA for the neuropeptides cholecystokinin (Cck, 48%) and calcitonin gene-related peptide (Calca, 13%), with minimal contribution from FoxP2+ PB neurons (2%). Axons from the PB produce an extensive terminal field in an unmyelinated region of the insular cortex, extending caudally into the entorhinal cortex, and arcing rostrally through the dorsolateral prefrontal cortex, with a secondary terminal field in the medial prefrontal cortex. In return, layer 5 neurons in the insular cortex and other prefrontal areas, along with a dense cluster of cells dorsal to the claustrum, send a descending projection to subregions of the PB that contain cortically projecting neurons. This information forms the neuroanatomical basis for testing PB–cortical interconnectivity in arousal and interoception.