IODP 地点1415で掘削されたはんれい岩の岩石学的および地球化学的特徴 : 東太平洋海嶺下の肥沃なマントルソースの証拠

ODP Expedition 345 aimed to drill lower crust gabbros at Hess deep rift (East Pacific Rise, 2°14’N-101°30’W), which is located near the junction between EPR and the Cocos, Nazca and Ridge. Lower crust oceanic gabbros were sampled on a about 200 m wide bench located on the intrarift southern slope between 4675 and 4850 m below sea level, and total of 11 holes (1415A to P) were drilled, among which two reached a depth over 110 m below seafloor (Holes 1415J and 1415P; see IODP Expedition 345 Scientific Report, 2013). Primitive troctolites and olivine-rich gabbros were the main lithologies recovered from these two holes. Shipboard data showed a whole rock chemistry with a high Mg# in concordance with their primitive nature. In a MOR system, olivine is a typical primitive mineral and orthoyroxene (Opx) usually appear late in the crystallization sequence, when the magma already reached a significant degree of differentiation. In spite Opx is not expected in any primitive lithology, this mineral is commonly present in Hole 1415P gabbros and associated with olivine. This curious association of cumulate Opx with olivine and other primitive minerals was also observed at a lower extent in some gabbros from IODP Hole 1256D, in the upper Hess Deep crustal section (ODP Hole 894G)We studied about 70 samples from Holes J and P, and 15 samples from the upper crust (ODP Hole 894G and rubbles from IODP site 1415) for their petrography and mineral chemistry. All samples are olivine gabbros and show an overall cumulate texture with ophitic to subophitic domain consisting of large clinopyroxenes enclosing plagioclase and olivine chadacrysts. Olivine is subhedral to sub-rounded and plagioclase appear as subhedral laths. Beside the main constituent phases in Olivine gabbros, a relatively high content of orthopyroxenes may be observed (≥ 5%). Three types of Opx textures may be distinguished in Opx-bearing olivine gabbros (1) recrystallized corona around olivine, (2) exsolution within clinopyroxene and (3) large prismatic or poikilitic grains. The third type is the most common and overall texture points to a crystallization order starting with olivine and plagioclase, and finishing with clinopyroxene and then orthopyroxene.In the upper crust, samples are less rich in olivine and mineral chemistry points to relatively differentiated characteristics compatible with a formation by fractional crystallization from a magma a MORB melt having undergone a certain degree of differentiation. In the lower crust, mineral chemistry show systematically primitive characteristics with high olivine forsterite content, clinopyroxene and orthopyroxene Mg# for all samples. Hole J gabbros show a clear evolution from the bottom to the top, with decreasing Mg# and increasing minor and trace elements contents in mafic minerals. Processes dominated by fractional crystallization can explain the genesis of the Hole 1415J gabbroic column. On the other hand, the narrow down hole variation ranges for Mg# in Opx (84-86%), Cpx (86-92%) and olivine (85-90%) in Hole 1415P, together with a a large scatter in minor and trace elements (Ti, Al, Cr, Ni, Mn, Yb, Cs, Zr, etc.), in Cpx and Opx suggests that, at a global scale, the gabbro column were only affected by a moderate degree of differentiation and melt/rock reaction leading to Mg/Fe ratio buffering played a major role in the formation process. However the relatively low Mg# (below 88%) values show that the reactant was rich in relatively differentiated mafic minerals with a general Mg# lower than in mantle rocks. Chemical zoning observed in the ophitic clinopyroxenes show that the crystallization process might be locally dominated by small-scale differentiation.Calculated compositions for liquids in equilibrium with Cpx and plagioclase, using both minor and trace elements are consistently between the EPR MORB and the Galapagos basalts chemical domains. In contrast, the melt in equilibrium with Opx in Hole P plot out of the MORB and OIB domain and is significantly richer in Ti. Mg# calculations on all the ferro-magnesian minerals show that Opx and olivine are in equilibrium while Cpx has a higher Mg# than the calculated Cpx in equilibrium with Opx These demonstrate that a two phases magmatic process occurred, in association with the melting of a enriched mantle source (similar to that producing enriched basalts at the Galapagos hotspot) to generate EPR lower gabbros: 1) Crystallization of a Mg/Fe ration buffered mush. The melt in this mush originated from an enriched mantle source, melts injected in the mush got buffered by a probable melt-rock reaction process occurring in the underlying troctolites. A certain degree of differentiation may occur in the mantle and troctolites, leading to stronger enrichment but the buffering event erased any chemical evidence of differentiation. The appearances of Opx at an early stage in the crystallization sequence suggest a Si-rich source compatible with pyroxenite melting. 2) Local differentiation leading to the crystallization of zoned Cpx in concurrence with Opx precipitation.MORB melts crystallizing in Hole 1415J are expelled out from the lower crust to the melt lens located at the top of the gabbro section. Enriched melts crystallizing in Hole 1415P are not observed in the basalts formed at the top of the section, this show that some melts produced in the mantle were not extracted from the basaltic mush to the melt lens. They entirely crystallized in the lower crust and are not expressed at the surface. Our study showed the limitation of the basaltic glasses method, sued up to now in order to calculate a general MORB or enriched mantle source

Exosomal RNA: Interplay and Therapeutic Potential

Exosomal RNA has emerged as a crucial mediator of intercellular communication, enabling the transfer of genetic information between cells. This intricate signaling system holds great promise for unraveling complex cellular processes and advancing therapeutic applications. This review provides an in-depth examination of the current state of knowledge regarding exosomal RNA, emphasizing its role in intercellular signaling and its relevance to various physiological and pathological conditions. Furthermore, we explore the potential therapeutic applications that leverage exosomal RNA, opening new avenues for innovative treatments across diverse medical domains. The nuanced interplay of exosomal RNA presents a fertile ground for further investigation and application, promising advancements in both fundamental biology and clinical interventions

Glycan analysis of human neutrophil granules implicates a maturation-dependent glycosylation machinery

Protein glycosylation is essential to trafficking and immune functions of human neutrophils. During granulopoiesis in the bone marrow, distinct neutrophil granules are successively formed. Distinct receptors and effector proteins, many of which are glycosylated, are targeted to each type of granule according to their time of expression, a process called "targeting by timing." Therefore, these granules are time capsules reflecting different times of maturation that can be used to understand the glycosylation process during granulopoiesis. Herein, neutrophil subcellular granules were fractionated by Percoll density gradient centrifugation, andN- andO-glycans present in each compartment were analyzed by LC-MS. We found abundant paucimannosidicN-glycans and lack ofO-glycans in the early-formed azurophil granules, whereas the later-formed specific and gelatinase granules and secretory vesicles contained complexN-andO-glycans with remarkably elongatedN-acetyllactosamine repeats with Lewis epitopes. Immunoblotting and histochemical analysis confirmed the expression of Lewis X and sialyl-Lewis X in the intracellular granules and on the cell surface, respectively. Many glycans identified are unique to neutrophils, and their complexity increased progressively from azurophil granules to specific granules and then to gelatinase granules, suggesting temporal changes in the glycosylation machinery indicative of "glycosylation by timing" during granulopoiesis. In summary, this comprehensive neutrophil granule glycome map, the first of its kind, highlights novel granule-specific glycosylation features and is a crucial first step toward a better understanding of the mechanisms regulating protein glycosylation during neutrophil granulopoiesis and a more detailed understanding of neutrophil biology and function

Isolation and Biophysical Study of Fruit Cuticles

The cuticle, a hydrophobic protective layer on the aerial parts of terrestrial plants, functions as a versatile defensive barrier to various biotic and abiotic stresses and also regulates water flow from the external environment.1 A biopolyester (cutin) and long-chain fatty acids (waxes) form the principal structural framework of the cuticle; the functional integrity of the cuticular layer depends on the outer \u27epicuticular\u27 layer as well as the blend consisting of the cutin biopolymer and \u27intracuticular\u27 waxes.2 Herein, we describe a comprehensive protocol to extract waxes exhaustively from commercial tomato (Solanum lycopersicum) fruit cuticles or to remove epicuticular and intracuticular waxes sequentially and selectively from the cuticle composite. The method of Jetter and Schäffer (2001) was adapted for the stepwise extraction of epicuticular and intracuticular waxes from the fruit cuticle.3,4 To monitor the process of sequential wax removal, solid-state cross-polarization magic-angle-spinning (CPMAS) 13C NMR spectroscopy was used in parallel with atomic force microscopy (AFM), providing molecular-level structural profiles of the bulk materials complemented by information on the microscale topography and roughness of the cuticular surfaces. To evaluate the cross-linking capabilities of dewaxed cuticles from cultivated wild-type and single-gene mutant tomato fruits, MAS 13C NMR was used to compare the relative proportions of oxygenated aliphatic (CHO and CH2O) chemical moieties. Exhaustive dewaxing by stepwise Soxhlet extraction with a panel of solvents of varying polarity provides an effective means to isolate wax moieties based on the hydrophobic characteristics of their aliphatic and aromatic constituents, while preserving the chemical structure of the cutin biopolyester. The mechanical extraction of epicuticular waxes and selective removal of intracuticular waxes, when monitored by complementary physical methodologies, provides an unprecedented means to investigate the cuticle assembly: this approach reveals the supramolecular organization and structural integration of various types of waxes, the architecture of the cutin-wax matrix, and the chemical composition of each constituent. In addition, solid-state 13C NMR reveals differences in the relative numbers of CHO and CH2O chemical moieties for wild-type and mutant red ripe tomato fruits. The NMR techniques offer exceptional tools to fingerprint the molecular structure of cuticular materials that are insoluble, amorphous, and chemically heterogeneous. As a noninvasive surface-selective imaging technique, AFM furnishes an effective and direct means to probe the structural organization of the cuticular assembly on the nm-μm length scale. The cuticle, a hydrophobic protective layer on the aerial parts of terrestrial plants, functions as a versatile defensive barrier to various biotic and abiotic stresses and also regulates water flow from the external environment. 1 A biopolyester (cutin) and long-chain fatty acids (waxes) form the principal structural framework of the cuticle; the functional integrity of the cuticular layer depends on the outer \u27epicuticular\u27 layer as well as the blend consisting of the cutin biopolymer and \u27intracuticular\u27 waxes. 2 Herein, we describe a comprehensive protocol to extract waxes exhaustively from commercial tomato ( Solanum lycopersicum ) fruit cuticles or to remove epicuticular and intracuticular waxes sequentially and selectively from the cuticle composite. The method of Jetter and Schäffer (2001) was adapted for the stepwise extraction of epicuticular and intracuticular waxes from the fruit cuticle. 3,4 To monitor the process of sequential wax removal, solid-state cross-polarization magic-angle-spinning (CPMAS) 13 C NMR spectroscopy was used in parallel with atomic force microscopy (AFM), providing molecular-level structural profiles of the bulk materials complemented by information on the microscale topography and roughness of the cuticular surfaces. To evaluate the cross-linking capabilities of dewaxed cuticles from cultivated wild-type and single-gene mutant tomato fruits, MAS 13 C NMR was used to compare the relative proportions of oxygenated aliphatic (CHO and CH 2 O) chemical moieties

Glycoproteome remodeling and organelle-specific N-glycosylation accompany neutrophil granulopoiesis

Neutrophils store microbicidal glycoproteins in cytosolic granules to fight intruding pathogens, but their granule distribution and formation mechanism(s) during granulopoiesis remain unmapped. Herein, we comprehensively profile the neutrophil N-glycoproteome with spatiotemporal resolution by analyzing four key types of intracellular organelles isolated from blood-derived neutrophils and during their maturation from bone marrow–derived progenitors using a glycomics-guided glycoproteomics approach. Interestingly, the organelles of resting neutrophils exhibited distinctive glycophenotypes including, most strikingly, highly truncated N-glycans low in α2,6-sialylation and Lewis fucosylation decorating a diverse set of microbicidal proteins (e.g., myeloperoxidase, azurocidin, neutrophil elastase) in the azurophilic granules. Excitingly, proteomics and transcriptomics data from discrete myeloid progenitor stages revealed that profound glycoproteome remodeling underpins the promyelocytic-to-metamyelocyte transition and that the glycophenotypic differences are driven primarily by dynamic changes in protein expression and less by changes within the glycosylation machinery. Notable exceptions were the oligosaccharyltransferase subunits responsible for initiation of N-glycoprotein biosynthesis that were strongly expressed in early myeloid progenitors correlating with relatively high levels of glycosylation of the microbicidal proteins in the azurophilic granules. Our study provides spatiotemporal insights into the complex neutrophil N-glycoproteome featuring intriguing organelle-specific N-glycosylation patterns formed by dynamic glycoproteome remodeling during the early maturation stages of the myeloid progenitors

Hyper-truncated Asn355- And Asn391-glycans modulate the activity of neutrophil granule myeloperoxidase

Myeloperoxidase (MPO) plays essential roles in neutrophil-mediated immunity via the generation of reactive oxidation products. Complex carbohydrates decorate MPO at discrete sites, but their functional relevance remains elusive. To this end, we have characterised the structure–biosynthesis–activity relationship of neutrophil MPO (nMPO). Mass spectrometry demonstrated that nMPO carries both characteristic under-processed and hyper-truncated glycans. Occlusion of the Asn355/Asn391-glycosylation sites and the Asn323-/Asn483-glycans, located in the MPO dimerisation zone, was found to affect the local glycan processing, thereby providing a molecular basis of the site-specific nMPO glycosylation. Native mass spectrometry, mass photometry and glycopeptide profiling revealed significant molecular complexity of diprotomeric nMPO arising from heterogeneous glycosylation, oxidation, chlorination and polypeptide truncation variants and a previously unreported low-abundance monoprotomer. Longitudinal profiling of maturing, mature, granule-separated and pathogen-stimulated neutrophils demonstrated that nMPO is dynamically expressed during granulopoiesis, unevenly distributed across granules and degranulated upon activation. We also show that proMPO-to-MPO maturation occurs during early/mid-stage granulopoiesis. While similar global MPO glycosylation was observed across conditions, the conserved Asn355-/Asn391-sites displayed elevated glycan hyper-truncation, which correlated with higher enzyme activities of MPO in distinct granule populations. Enzymatic trimming of the Asn355-/Asn391-glycans recapitulated the activity gain and showed that nMPO carrying hyper-truncated glycans at these positions exhibits increased thermal stability, polypeptide accessibility and ceruloplasmin-mediated inhibition potential relative to native nMPO. Finally, molecular modelling revealed that hyper-truncated Asn355-glycans positioned in the MPO-ceruloplasmin interface are critical for uninterrupted inhibition. Here, through an innovative and comprehensive approach, we report novel functional roles of MPO glycans, providing new insight into neutrophil-mediated immunity

Shallow-water hydrothermal venting linked to the Palaeocene–Eocene Thermal Maximum

The Palaeocene–Eocene Thermal Maximum (PETM) was a global warming event of 5–6 °C around 56 million years ago caused by input of carbon into the ocean and atmosphere. Hydrothermal venting of greenhouse gases produced in contact aureoles surrounding magmatic intrusions in the North Atlantic Igneous Province have been proposed to play a key role in the PETM carbon-cycle perturbation, but the precise timing, magnitude and climatic impact of such venting remains uncertain. Here we present seismic data and the results of a five-borehole transect sampling the crater of a hydrothermal vent complex in the Northeast Atlantic. Stable carbon isotope stratigraphy and dinoflagellate cyst biostratigraphy reveal a negative carbon isotope excursion coincident with the appearance of the index taxon Apectodinium augustum in the vent crater, firmly tying the infill to the PETM. The shape of the crater and stratified sediments suggests large-scale explosive gas release during the initial phase of vent formation followed by rapid, but largely undisturbed, diatomite-rich infill. Moreover, we show that these vents erupted in very shallow water across the North Atlantic Igneous Province, such that volatile emissions would have entered the atmosphere almost directly without oxidation to CO2 and at the onset of the PETM

Shallow-water hydrothermal venting linked to the Palaeocene–Eocene Thermal Maximum

The Palaeocene–Eocene Thermal Maximum (PETM) was a global warming event of 5–6 °C around 56 million years ago caused by input of carbon into the ocean and atmosphere. Hydrothermal venting of greenhouse gases produced in contact aureoles surrounding magmatic intrusions in the North Atlantic Igneous Province have been proposed to play a key role in the PETM carbon-cycle perturbation, but the precise timing, magnitude and climatic impact of such venting remains uncertain. Here we present seismic data and the results of a five-borehole transect sampling the crater of a hydrothermal vent complex in the Northeast Atlantic. Stable carbon isotope stratigraphy and dinoflagellate cyst biostratigraphy reveal a negative carbon isotope excursion coincident with the appearance of the index taxon Apectodinium augustum in the vent crater, firmly tying the infill to the PETM. The shape of the crater and stratified sediments suggests large-scale explosive gas release during the initial phase of vent formation followed by rapid, but largely undisturbed, diatomite-rich infill. Moreover, we show that these vents erupted in very shallow water across the North Atlantic Igneous Province, such that volatile emissions would have entered the atmosphere almost directly without oxidation to CO2 and at the onset of the PETM

Search for continuous gravitational wave emission from the Milky Way center in O3 LIGO--Virgo data

We present a directed search for continuous gravitational wave (CW) signals emitted by spinning neutron stars located in the inner parsecs of the Galactic Center (GC). Compelling evidence for the presence of a numerous population of neutron stars has been reported in the literature, turning this region into a very interesting place to look for CWs. In this search, data from the full O3 LIGO--Virgo run in the detector frequency band $[10,2000]\rm~Hz$ have been used. No significant detection was found and 95$\%$ confidence level upper limits on the signal strain amplitude were computed, over the full search band, with the deepest limit of about $7.6\times 10^{-26}$ at $\simeq 142\rm~Hz$. These results are significantly more constraining than those reported in previous searches. We use these limits to put constraints on the fiducial neutron star ellipticity and r-mode amplitude. These limits can be also translated into constraints in the black hole mass -- boson mass plane for a hypothetical population of boson clouds around spinning black holes located in the GC.Comment: 25 pages, 5 figure