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The Middle Triassic Luoping Biota in south-west China represents the inception of modern marine ecosystems, with abundant and diverse arthropods, fishes and marine reptiles, indicating recovery from the Permian–Triassic mass extinction. Here we report a new specimen of the predatory marine reptile Diandongosaurus, based on a nearly complete skeleton. The specimen is larger than most other known pachypleurosaurs, and the body shape, caniniform teeth, clavicle with anterior process, and flat distal end of the anterior caudal ribs show its affinities with Diandongosaurus acutidentatus, while the new specimen is approximately three times larger than the holotype. The morphological characters indicate that the new specimen is an adult of D. acutidentatus, allowing for ontogenetic variation. The fang-like teeth and large body size confirm it was a predator, but the amputated hind limb on the right side indicate itself had been predated by an unknown hunter. Predation on such a large predator reveals that predation pressure in the early Mesozoic was intensive, a possible early hint of the Mesozoic Marine Revolution.

Herein, we show that Zn2+ binds to phosphatidylserine (PS) lipids in supported lipid bilayers (SLBs), forming a PS-Zn2+ complex with an equilibrium dissociation constant of ∼100 μM. Significantly, ...

The classical taxonomy of fossil invertebrates is based on subjective judgments of morphology, which can cause confusion, because there are no codified standards for the classification of genera. Here, we explore the validity of the genus taxonomy of 75 species and morphospecies of the Follicucullidae, a late Paleozoic family of radiolarians, using a new method, Hayashi's quantification theory II (HQT-II), a general multivariate statistical method for categorical datasets relevant to discriminant analysis. We identify a scheme of 10 genera rather than the currently accepted 3 genera (Follicucullus,Ishigaconus, andParafollicucullus). As HQT-II cannot incorporate stratigraphic data, a phylogenetic tree of Follicucullidae was reconstructed for 38 species using maximum parsimony. Six lineages emerged, roughly in concordance with the results of HQT-II. Combined with parsimony ancestral state reconstruction, the ancestral group of this family isHaplodiacanthus. Five other groups were discriminated, theParafollicucullus,Curvalbaillella,Pseudoalbaillella,Longtanella, andFollicucullus–Cariverlineages. The morphological evolution of these lineages comprises a minimum essential list of eight states of four traits. HQT-II is a novel discriminant analytical multivariate method that may be of value in other taxonomic problems of paleobiology.

Vibrational sum frequency spectroscopy (VSFS) and pressure-area Langmuir trough measurements were used to investigate the binding of alkali metal cations to eicosyl sulfate (ESO

Weakly hydrated anions help to solubilize hydrophobic macromolecules in aqueous solutions, but small molecules comprising the same chemical constituents precipitate out when exposed to these ions. Here, this apparent contradiction is resolved by systematically investigating the interactions of NaSCN with polyethylene oxide oligomers and polymers of varying molecular weight. A combination of spectroscopic and computational results reveals that SCN− accumulates near the surface of polymers, but is excluded from monomers. This occurs because SCN− preferentially binds to the centre of macromolecular chains, where the local water hydrogen-bonding network is disrupted. These findings suggest a link between ion-specific effects and theories addressing how hydrophobic hydration is modulated by the size and shape of a hydrophobic entity. Weakly hydrated anions solubilize macromolecules but cause small molecules that are made from identical chemical constituents to precipitate out of aqueous solutions. Now, this phenomenon has been understood by demonstrating that the binding of anions to polymers is regulated by molecular curvature and interfacial water structure.

A new genus and species, Micromartinia kwangsiella gen. et sp. nov., is erected based on material from the Talung Formation (upper Changhsingian), Guangxi, South China. Based on a phylogenetic anal...

Aqueous two-phase system (ATPS) formation is the macroscopic completion of liquid–liquid phase separation (LLPS), a process by which aqueous solutions demix into 2 distinct phases. We report the temperature-dependent kinetics of ATPS formation for solutions containing a monoclonal antibody and polyethylene glycol. Measurements are made by capturing dark-field images of protein-rich droplet suspensions as a function of time along a linear temperature gradient. The rate constants for ATPS formation fall into 3 kinetically distinct categories that are directly visualized along the temperature gradient. In the metastable region, just below the phase separation temperature, T(ph), ATPS formation is slow and has a large negative apparent activation energy. By contrast, ATPS formation proceeds more rapidly in the spinodal region, below the metastable temperature, T(meta), and a small positive apparent activation energy is observed. These region-specific apparent activation energies suggest that ATPS formation involves 2 steps with opposite temperature dependencies. Droplet growth is the first step, which accelerates with decreasing temperature as the solution becomes increasingly supersaturated. The second step, however, involves droplet coalescence and is proportional to temperature. It becomes the rate-limiting step in the spinodal region. At even colder temperatures, below a gelation temperature, T(gel), the proteins assemble into a kinetically trapped gel state that arrests ATPS formation. The kinetics of ATPS formation near T(gel) is associated with a remarkably fragile solid-like gel structure, which can form below either the metastable or the spinodal region of the phase diagram.

The anomalously high mobility of hydroxide and hydronium ions in aqueous solutions is related to proton transfer and structural diffusion. The role of counterions in these solutions, however, is often considered to be negligible. Herein, we explore the impact of alkali metal counter cations on hydroxide solvation and mobility. Impedance measurements demonstrate that hydroxide mobility is attenuated by lithium relative to sodium and potassium. These results are explained by ab initio molecular dynamics simulations and experimental vibrational hydration shell spectroscopy, which reveal substantially stronger ion pairing between OH- and Li+ than with other cations. Hydration shell spectra and theoretical vibrational frequency calculations together imply that lithium and sodium cations have different effects on the delocalization of water protons donating a hydrogen bond to hydroxide. Specifically, lithium leads to enhanced proton delocalization compared with sodium. However, proton delocalization and the overall diffusion process are not necessarily correlated.

Sphingosine-1-phosphate (S1P) is a sphingolipid metabolite that is thought to participate in the regulation of many physiological processes and may play a key role in several diseases. Herein, we found that Cu2+ binds tightly to supported lipid bilayers (SLBs) containing S1P. Specifically, we demonstrated via fluorescence assays that Cu2+–S1P binding was bivalent and sensitive to the concentration of S1P in the SLB. In fact, the apparent equilibrium dissociation constant, KDApp, tightened by a factor of 132 from 4.5 μM to 34 nM as the S1P density was increased from 5.0 to 20 mol %. A major driving force for this apparent tightening was the more negative surface potential with increasing S1P concentration. This potential remained unaltered upon Cu2+ binding at pH 7.4 because two protons were released for every Cu2+ that bound. At pH 5.4, however, Cu2+ could not outcompete protons for the amine and no binding occurred. Moreover, at pH 9.4, the amine was partially deprotonated before Cu2+ binding and the sur...

Herein, we show that Zn

Phosphatidylinositol 4,5-bisphosphate (PIP2) has a significantly lower mobile fraction than most other lipids in supported lipid bilayers (SLBs). Moreover, the fraction of mobile PIP2 continuously decreases with time. To explore this, a bilayer unzipping technique was designed to uncouple the two leaflets of the SLB. The results demonstrate that PIP2 molecules in the top leaflet are fully mobile, while the PIP2 molecules in the lower leaflet are immobilized on the oxide support. Over time, mobile PIP2 species flip from the top leaflet to the bottom leaflet and become trapped. It was found that PIP2 flipped between the leaflets through a defect-mediated process. The flipping could be completely inhibited when holes in the bilayer were backfilled with bovine serum albumin (BSA). Moreover, by switching from H2O to D2O, it was shown that the primary interaction between PIP2 and the underlying substrate was due to hydrogen bond formation, which outcompeted electrostatic repulsion. Using substrates with fewer surface silanol groups, like oxidized polydimethylsiloxane, led to a large increase in the mobile fraction of PIP2. Moreover, PIP2 immobilization also occurred when the bilayer was supported on a protein surface rather than glass. These results may help to explain the behavior of PIP2 on the inner leaflet of the plasma membrane, where it is involved in attaching the membrane to the underlying cytoskeleton.

Ibuprofen (IBU) interacts with phosphatidylcholine membranes in three distinct steps as a function of concentration. In a first step (

Wu, H.T., He, W.H., Shi, G.R., Zhang, K.X., Yang, T.L., Zhang, Y., Xiao, Y.F., Chen, B. & Wu, S.B., XX.XXXX.2018. A new Permian–Triassic boundary brachiopod fauna from the Xinmin section, southwest...

A quantitative investigation of the ecological changes of shallow-marine benthos was undertaken at the Permian–Triassic boundary section at Zhongzhai, South China. The studied fossil material primarily included brachiopods and bivalves owing to their abundance throughout the section, but other subordinate taxonomic groups including ostracods and microgastropods were also integrated for discussion. Overall, a succession of three benthonic paleocommunities was recognized representing three connected ecological evolutionary stages across the Permian–Triassic transition. Both Stage 1 and Stage 2 paleocommunities predated the end-Permian boundary mass extinction, and were characterized by relatively high diversity of brachiopods and bivalves, with no or very rare other taxa. Approaching the end-Permian mass extinction and the PTB itself, the paleocommunity abruptly changed and was replaced by the Stage 2 paleocommunity that was characterized by a relatively low Shannon's diversity (H) coupled with a high Simpson's dominance index (D) and, most notably, a changeover from Neochonetes to Tethyochonetes (both are brachiopod genera) as the most significant ecological dominants. This Simpson's dominance index (D) shift correlates well with food shortage (i.e. much reduced terrestrial influx and acritarch abundance), and is therefore interpreted to signify, possibly, intensified interspecific competitions with Tethyochonetes seemingly outcompeting Neochonetes presumably due to its preadapted smaller body size. The post-extinction (Stage 3) paleocommunity is distinguished by a highly characteristic low-diversity and high-abundance fauna comprised mainly of lingulid brachiopods, Claraia bivalves, microgastropods and ostracods, suggesting a unique and highly stressful ecological regime. In this paleocommunity, Claraia might have acted like a “disaster taxon” and, as such, its ecological functional role in the paleocommunity was activated and elevated because of exceptional ecological conditions (e.g., anoxia, hyperthermal and/or severe food shortage). From the studied section, a number of ecological traits including species abundance distribution, Shannon's diversity (H), community dominance and body-size structure were identified as demonstrating significant changes accompanying community replacement prior to the end-Permian mass extinction. The fact that these changes preceded the mass extinction may suggest that these traits could represent some early warning signals for an impending ecological regime shift. This extended interpretation clearly has significant implications for modern ecological studies to predict future impending ecological regime shifts.

As the largest intracontinental basin in the Tibetan Plateau hinterland, the Hoh Xil Basin is an ideal area for exploring the coupled history of climate-tectonic relationships in the plateau's interior. However, the detailed paleoenvironmental research on the Hoh Xil Basin is quite insufficient. In this study, we collected palynological and ostracod samples from well-exposed Cenozoic lacustrine strata in the Hoh Xil Basin to reconstruct the paleoenvironment and paleoelevation of the Hoh Xil Basin. Based on the discovery of two key index fossils (Austrocypris cf. posticaudata and Lychnothamnus vectensis), we propose the latest Eocene-early Oligocene (latest Priabonian-earliest Rupelian) age for the strata of the Yaxicuo Formation in the Tongtianhe section. The palynological assemblage suggests that the Hoh Xil Basin was dominated by temperate broadleaved forest and that a warm climate prevailed in this region during the latest Eocene-early Oligocene. Roughly consistent with the overall warm climate confirmed by palynological evidence, the ostracod record indicates that a large freshwater lake existed within the warm environment of the Hoh Xil Basin during the latest Eocene-early Oligocene. By using the coexistence approach (CoA) to evaluate the fossil palynological assemblage, combined with the calibration of the effects of temperature differences and lapse rates, a paleoelevation of 2700 ± 200 m a.s.l. was estimated for the Hoh Xil Basin during the latest Eocene-early Oligocene, representing the height between the basin lake and the crests of the surrounding mountains.

Research on the dynamics of body-size changes in varied water depths can provide important insights into the evolution of palaeoenvironments through time. This paper attempts to investigate how the body sizes of two most commonly found chonetid brachiopod species in the uppermost Permian in South China varied with palaeo-bathymetry. The result shows that there is a broadly negative correlation between the latest Permian brachiopod body size and water depth. There is no simple singular variable that could explain this correlation because bathymetry is correlated, either linearly or nonlinearly, to food availability, redox condition and habitat temperature, as well as substrate conditions. Overall, we found that both oxygen and food availability played a more important role in controlling the differences of body sizes, and specifically several depressed factors (low food availability, anoxia, or abnormal temperature) have compounded and caused small body sizes in deeper waters during the latest Permian. We propose that the brachiopod miniaturization during the Permian-Triassic crisis in South China was collectively driven by anoxia, food restriction and high temperature.

A combination of Fourier transform infrared and phase transition measurements as well as molecular computer simulations, and thermodynamic modeling were performed to probe the mechanisms by which guanidinium salts influence the stability of the collapsed versus uncollapsed state of an elastin-like polypeptide (ELP), an uncharged thermoresponsive polymer. We found that the cation's action was highly dependent upon the counteranion with which it was paired. Specifically, Gnd+ was depleted from the ELP/water interface and was found to stabilize the collapsed state of the macromolecule when paired with well-hydrated anions such as sulfate. Stabilization in this case occurred via an excluded volume (or depletion) effect, whereby sulfate was strongly partitioned away from the ELP/water interface. Intriguingly, at low salt concentrations, Gnd+ was also found to stabilize the collapsed state of the ELP when paired with SCN-, which is a strong binder for the ELP. In this case, the anion and cation were both found to be enriched in the collapsed state of the polymer. The collapsed state was favored because the Gnd+ crosslinked the polymer chains together. Moreover, the anion helped partition Gnd+ to the polymer surface. At higher salt concentrations (>1.5 M), GndSCN switched to stabilizing the uncollapsed state because a sufficient amount of Gnd+ and SCN- partitioned to the polymer surface to prevent cross-linking from occurring. Finally, in a third case, it was found that salts which interacted in an intermediate fashion with the polymer (e.g. GndCl) favored the uncollapsed conformation at all salt concentrations., 20 pages, 6 figures

The global palaeobiogeographic distributions of two resembling genera, Neochonetes and Fusichonetes (Brachiopoda), from the Carboniferous to Griesbachian are analysed. This analysis provides insight into the biotic response of two related genera to changing palaeoclimate, regional tectonics, and environmental crises. Neochonetes originated in the equatorial area in the Mississippian, and it mostly retained this position during the peak of the glaciation in the Carboniferous–Permian ice age (namely in the Pennsylvanian). Neochonetes then dispersed globally during the Cisuralian when the climate became warmer and the ice sheet started to retreat. In the Guadalupian and Lopingian, following the closure of the Ural seaway at the end of the Cisuralian and the regression at the end-Guadalupian, Neochonetes almost disappeared in the western part of Gondwana. Subsequently during the Lopingian the genus retracted to the middle- and low-latitude Palaeo-Tethys and Tethys. In comparison, Fusichonetes originated in the equatorial area in the late Guadalupian and was still present in that area in the Lopingian. Both genera occurred only in South China in the Griesbachian. It is inferred that this could be related, not only to the deteriorated palaeoenvironmental conditions (e.g., anoxia, global warming) leading up to the extinction of most of the Neochonetes and Fusichonetes species in other areas, but also to the better physiological adaptation of the smaller shells of Neochonetes and Fusichonetes species in South China.

Sphingosine-1-phosphate (S1P) is a sphingolipid metabolite that is thought to participate in the regulation of many physiological processes and may play a key role in several diseases. Herein, we found that Cu

The interfacial water structure and phosphate group hydration of 1,2-dioleoyl- sn-glycero-3-phosphatidylcholine monolayers were investigated at air/water interfaces. Both vibrational sum frequency spectroscopy (VSFS) and Langmuir monolayer compression measurements were made. The PC lipids oriented water molecules predominantly through their phosphate-choline (P-N) dipoles and carbonyl moieties. Upon the introduction of low concentrations of 1,2-dioleoyl-3-trimethylammonium propane (DOTAP), a positively charged double chain surfactant, the TAP headgroups were attracted to the phosphate moieties on adjacent PC lipids. This attraction caused the monolayers to contract, expelling water molecules that were hydrogen bonded to the phosphate groups. Moreover, amplitude of the OH stretch signal decreased. At higher DOTAP concentrations, the positive charge on the monolayer caused an increase in the area per headgroup and water molecules in the near-surface bulk region became increasingly aligned. Under these latter conditions, the OH stretch amplitude was linearly proportional to the surface potential. By contrast, introducing 1,2-dioleoyl- sn-glycero-3-phosphatidylglycerol, a negatively charged lipid, did not change the area per lipid or the phosphate-water hydrogen bonding network. As the interfacial potential grew more negative, the OH stretch amplitude increased continuously. Significantly, changes in the interfacial water spectrum were independent of the chemistry employed to create the positive or negative interfacial potential. For example, Ca2+ and tetracaine (both positively charged) disrupted the water structure similarly to low DOTAP concentrations, whereas SCN- and ibuprofen (both negatively charged) enhanced the water structure. These results suggest a direct correlation amongst the interfacial water structure, area per lipid, and surface charge density.

This paper has undertaken a quantitative and statistical analysis of brachiopod body-size changes through the marine Permian–Triassic boundary section at Zhongzhai, Guizhou Province, South China, and found that (1) pre-mass extinction dwarfing is evident for at least the rugosochonetid species chosen for this study; (2) Tethyochonetes species reduced their size earlier than that in the Neochonetes species; and (3) no significant size reduction occurred in the newly evolved species of these two genera. Inter-species competition for resources between Neochonetes species and Tethyochonetes species and the reduction of food supply in the upper part of the uppermost Permian is here proposed to explain these observed stratigraphic patterns of brachiopod body-size changes throughout the Zhongzhai section. In the case of the newly evolved species showing no significant body-size change, morphological innovations (adaptations) in the process of speciation are considered to have significantly enhanced these newly evolved species' flexibility and survival in coping with degrading environmental conditions.

New analysis of Permian–Triassic brachiopod assemblages and body-size changes in South China provides insights into the process of the environmental crisis in the lead up to the end-Permian mass extinction. The recently discovered Daoduishan section of South China can be considered as an important auxiliary section for the study of brachiopods at the Meishan Section D of South China, the GSSP of the Permian–Triassic Boundary (PTB). This paper studied changes of the brachiopod assemblages and body sizes through the upper part of the Changxing Formation and basal Yinkeng Formation of Daoduishan. The results show that significant changes of brachiopod assemblages took place between Beds 24e and 26. Brachiopods?Prelissorhynchia sp. and Paracruirithyris pygmaea are the dominators in Beds 14–24e, while Tethyochonetes pigmaea and Paryphella spp. are the dominators in Beds 26–29. Body sizes of brachiopods significantly decreased between Beds 24e and 26 and then maintained smaller means in Beds 27–29. Studies of brachiopod morphological features indicate both Tethyochonetes and Paryphella had advantageous adaptations enabling them to copy with living in an anoxic/dysoxic and/or low-productivity environment during the Permian–Triassic crisis.

The extinct legume genus Podocarpium first appeared in the middle Eocene of South China and then became widely distributed throughout Eurasia during the Oligocene and Miocene. Fossil records from Central Asia are important for understanding the patterns of floristic change of Podocarpium between Eastern Asia and Europe, but they are relatively rare. Here, we describe well-preserved fossil fruits and leaves of Podocarpium podocarpum (A. Braun) Herendeen from the early Oligocene (Rupelian) of the Qaidam Basin, northwest China. Morphological comparison among fossil fruits of all Podocarpium reported so far confirms the difference in fruit shape between Podocarpium eocenicum and P. podocarpum, and shows a decrease in fruit size during the Oligocene, which might be a response from this thermophilous plant to a cooler condition. The presence of P. podocarpum in the early Oligocene of Qaidam suggests that the Qaidam Basin might play an important role in the migration of this genus between Eastern Asia and Europe during the early Oligocene. Moreover, the expansion of Podocarpium in China during the Cenozoic appears to be strongly influenced by the East Asia monsoon development.

The ability of cells or cell components to move in response to chemical signals is critical for the survival of living systems. This motion arises from harnessing free energy from enzymatic catalysis. Artificial model protocells derived from phospholipids and other amphiphiles have been made and their enzymatic-driven motion has been observed. However, control of directionality based on chemical cues (chemotaxis) has been difficult to achieve. Here we show both positive or negative chemotaxis of liposomal protocells. The protocells move autonomously by interacting with concentration gradients of either substrates or products in enzyme catalysis, or Hofmeister salts. We hypothesize that the propulsion mechanism is based on the interplay between enzyme-catalysis-induced positive chemotaxis and solute-phospholipid-based negative chemotaxis. Controlling the extent and direction of chemotaxis holds considerable potential for designing cell mimics and delivery vehicles that can reconfigure their motion in response to environmental conditions.

This paper describes a new genusLiaous, withL. shaiwensisHe and Chen n. gen. n. sp. as the type species, from the Xinyuan Formation of Anisian age in Ziyun, southern Guizhou, China. The phylogenetic tree revealed by the parsimony analysis shows thatLiaousis closely allied to bothMentzeliaQuenstedt, 1871 andParamentzeliaXu, 1978 of the subfamily Mentzeliinae. A new classification scheme for the Spiriferinoidea is also proposed based on a phylogenetic tree of the superfamily indicated by parsimony analysis. The Spiriferinoidea includes three families and nine subfamilies. Three new subfamilies—Madoinae He and Chen, new subfam., Qinghaispiriferininae He and Chen, new subfam., and Triadispirinae He and Chen, new subfam. are proposed.Liaous shaiwensisHe and Chen n. gen. n. sp. is found in thePosidonia wengensis-Liaous shaiwensis(P-L) paleocommunity, which is dominated by r-strategists (i.e., organisms defined by a fauna with a high dominance and small body sizes) and has a low diversity and high dominance. The P-L paleocommunity therefore has little similarity to its coeval communities from the Anisian Stage of South China and instead it appears more similar to the Lower Triassic shelly faunas in community structures. This paleocommunity is interpreted to have inhabited a relatively deep, low-energy, dysaerobic offshore basin/slope setting with the influence of episodic storms.

The significant increase of abundance and expansion of depositional environments that produced unusual sediments in the Early Triassic indicates stressed ecosystems in the aftermath of the Permian–Triassic (P–Tr) mass extinction. As one of the characteristically common Early Triassic carbonate sediments, ooids provide a potential proxy to refine understanding of the biotic and environmental stresses during this time through analysis of their formation and size variations. A case study from South China and a global review are presented herein to explore the interrelations between occurrences of oolites and ooid size variations with biotic and environmental changes. Correlations between oolites and various biotic and environmental changes suggest a strong correspondence with episodes of euxinia/dysoxia but less so with skeleton abundance and temperature changes, implying complex interactions between multiple biotic and environmental anomalies in the aftermath of the P–Tr extinction. The episodic occurrence pattern of oolites from the end-Permian through the Early Triassic coincides with the multiple crises of the P–Tr mass extinction and its aftermath. The global increase in size of ooids during the early stage of the P–Tr mass extinction aftermath indicates the most severe and extensive conditions of devastation for ecosystems. The single occurrence of giant ooids in the Nanpanjiang Basin within the Olenekian implies local higher ecosystem stress than other areas. This analysis of ooid size variations and the paleoceanographic implications suggests that the size of ooids could be an appropriate quantified sedimentary proxy for ecosystem devastation with varied temporal and spatial ranges.

Phosphatidylethanolamine (PE) is notoriously difficult to incorporate into model membrane systems, such as fluid supported lipid bilayers (SLBs), at high concentrations because of its intrinsic negative curvature. Using fluorescence-based techniques, we demonstrate that having fewer sites of unsaturation in the lipid tails leads to high-quality SLBs because these lipids help to minimize the curvature. Moreover, shorter saturated chains can help maintain the membranes in the fluid phase. Using these two guidelines, we find that up to 70 mol % PE can be incorporated into SLBs at room temperature and up to 90 mol % PE can be incorporated at 37 °C. Curiously, conditions under which three-dimensional tubules project outward from the planar surface as well as conditions under which domain formation occurs can be found. We have employed these model membrane systems to explore the ability of Ni2+ to bind to PE. It was found that this transition metal ion binds 1000-fold tighter to PE than to phosphatidylcholine l...

Liposomes loaded with the rhenium compound (bis-dimethylsulfoxido-cis-tetrachlorodi-μ-pivalatodirhenium(III) (cis-Re2((CH3)3CCOO)2Cl4.2DMSO, I) and cisplatin in the molar ratio of 4:1 as well as those loaded only with I were synthesized and characterized by scanning electron microscopy, transmission electron microscopy, dynamic light scattering and electronic absorption spectroscopy. The relative stability of liposomes loaded with I is reflected by a minimal change in the electronic absorption spectra over a period of 8 days whereas the stability of those loaded with both drugs is lower, which we ascribe to the formation of new Re-Pt species inside the liposomes. Furthermore, the investigations of the co-encapsulation effects on the anticancer activity of the Re-Pt system were undertaken. Importantly, the co-encapsulated liposomes exhibit synergistic or additive anticancer activities in vivo, e.g. introduction of these liposomes into tumor-bearing rats demonstrated their antianemic, nephro- and hepato-protecting effects. These liposomes, which are active in cancer treatment, protect the dirhenium compounds from hydrolysis and preserve the biological properties of the Re-Pt hybrid. This study reveals the importance of combined therapy in nanotechnology and medicine.

This paper describes 45 brachiopod species (including 15 undetermined species) in 23 genera belonging to seven orders (Productida, Spiriferida, Athyridida, Orthida, Orthotetida, Rhynchonellida and Lingulida) from the Talung Formation (Changhsingian, latest Permian) of the marine deep-water facies of South China. Two new genera are proposed: Chaohochonetes and Parapygmochonetes; along with nine new species: Tethyochonetes rectangularis, Tethyochonetes? sinuata, Chaohochonetes triangusinuata, Neochonetes (Zhongyingia?) liaoi, Neochonetes (Huangichonetes?) wufengensis, Paryphella majiashanensis, Paryphella minuta, Parapygmochonetes parvulus and Meekella sparsiplicata. The taxonomic composition, significant morphological features and palaeoecological implications of this deep-water brachiopod fauna are summarized, and the fauna is compared with the Permian–Triassic boundary (PTB) mixed brachiopod fauna of South China. The Changhsingian (latest Permian) deep-water brachiopod fauna of South China shares some co...

New conodont samples have been systematically collected at high stratigraphic resolution from the upper part of the Longtan Formation through to the lower part of the Yelang Formation at the Zhongzhai section, southwestern Guizhou Province, South China, in an effort to verify the first local occurrence of Hindeodus parvus in relation to the Permian–Triassic boundary at this section. The resampled conodont fauna from the Permian–Triassic boundary interval comprises five identified species and two undetermined species in Hindeodus and Clarkina . Most importantly, the first local occurrence of Hindeodus parvus is found for the first time from the bottom of Bed 28a, 18 cm lower than the previously reported first local occurrence of this species at this section. Considering the previously accepted PTB at the Zhongzhai section, well calibrated by conodont biostratigraphy, geochronology and carbon isotope chemostratigraphy, this lower (earlier) occurrence of H . parvus suggests that this critical species could occur below the Permian–Triassic boundary. As such, this paper provides evidence that (1) the first local occurrences of H . parvus are diachronous in different sections with respect to the PTB defined by the First Appearance Datum (FAD) of this species at its GSSP section in Meishan, China and that (2) the lower stratigraphic range of H . parvus should now be extended to latest Permian.

Phospholipids play important roles in numerous cell membrane activities, such as protein binding, intracellular signaling, apoptosis, and the synthesis of biomolecules.1−5 Different phospholipids and fatty acids can be interconverted through various enzymatic reactions on the surface of lipid membranes.5 This includes phosphatidic acid (PA), which typically accounts for 1–4% of the total lipid content of eukaryotic cells.6 PA is a central lipid in signaling reactions and serves as a precursor for the biosynthesis of many other lipids.5,7−9 It is also involved in regulating membrane curvature and the vesicle fusion process.1,9−12 Activated by Ca2+, phospholipase D (PLD) catalyzes the hydrolysis of phosphatidylcholine (PC) to phosphatidic acid (PA) (Figure ​(Figure11A).13,14 Such enzymatic activity is closely related to intracellular signal transduction, the presence of cancer cells, and other PA-related processes.9 A “ping-pong-like” catalytic mechanism has been proposed for PLD activity.15 Namely, PC binds covalently with PLD to form a PA-PLD complex with the release of choline. The P–O bond between PA and PLD is then cleaved by the nucleophilic attack of water on the distal phosphate ester.15 Real-time atomic force microscopy (AFM) measurements have demonstrated that PLD is released from the lipid bilayer surface after the reaction is completed.16 Figure 1 (A) Illustration of PLD catalyzed POPC to POPA conversion. (B) Illustration of the effect of negatively charged POPA lipids on the focusing position of a streptavidin biomarker in an EEF experiment. Typically, phospholipase reactions on phospholipids are monitored by measuring the concentration of the products which are evolved. For example, PLD activity has been monitored by measuring the concentration of free choline released from PC using a two-step chromogenic assay or using isotopically labeled choline.13,17−20 In the chromogenic assay, the released choline is first transformed into betaine and H2O2 by choline oxidase. With 4-aminoantipyrine and sodium 2-hydroxy-3,5-dichlorobenzenesulfonate, H2O2 then produces quinone dye in the presence of peroxidase. The concentration of the quinone dye can be determined by measuring its absorbance around 500 nm.13,18,19 In this case, successive experiments can result in compounded errors and makes the assay less accurate. Indeed, the concentration of the biologically relevant product, PA, has been particular difficult to measure, simply because PA is a component of many other phospholipids and lacks unique absorption peaks that can readily be differentiated from other lipids. As a consequence, it has been difficult to directly monitor the PLD-catalyzed PC to PA conversion directly within intact lipid membranes. As such, there are current efforts directed toward developing new assays for the formation of PA in PLD-catalyzed PC hydrolysis. This includes very recent work exploiting the use of ion current passing through a nanopore in a black lipid membrane to follow PA production.21,22 Herein, we report a simple and straightforward method that can directly determine the percentage of POPA in supported lipid bilayers (SLBs) by monitoring the electrophoretic-electroosmotic focusing (EEF) position of a fluorescently tagged streptavidin molecule that is bound to the membrane via a biotinylated lipid.23 Negatively charged membrane-bound proteins like streptavidin can be focused on SLBs containing negatively charged lipids by counteracting electrophoretic and electroosmotic forces (Figure ​(Figure11B).21 These forces exactly balance each other at the focusing position. Moreover, the zeta potential of a focused protein should be equal to the local surface zeta potential at the focusing position, which is directly related to the local surface charge density. As such, streptavidin or other membrane bound proteins can be exploited as indicators of the local surface charge density. When an external electric field is applied laterally across an SLB, negatively charged lipids spontaneously build up a concentration gradient, generating higher negative surface charge density near the positive electrode.21,2425 The concentration of negatively charged lipids in the membrane strongly affects the focusing position of the protein because the shape and magnitude of the gradient that can be formed are directly involved.23 This assay exploits the fact that POPC is uncharged (zwitterionic), while POPA is negatively charged at neutral pH (Figure ​(Figure1A).1A). Thus, the PLD enzymatic reaction can convert an initially neutral bilayer into one that contains negatively charged lipids. After the reaction is completed and the enzyme is washed away, the concentration of the negatively charged components can be monitored via an EFF assay, when streptavidin is subsequently attached to the surface (Figure ​(Figure2).2). Specifically, the focusing position of the streptavidin marker will migrate ever closer to the negative electrode as the concentration of POPA is increased (Figure ​(Figure11B). Figure 2 Schematic diagram of the experimental procedure for an EFF assay. In a first step, PLD is introduced above the POPC bilayer in the presence of Ca2+. This converts neutral POPC lipids to POPA. After the reaction, PLD and Ca2+ are removed from the SLB surface by ...

Determining the provenance of Cenozoic strata in the Qaidam Basin is key to understanding the basin-mountain coupling history in the northern Tibetan Plateau (TP). However, the specific source areas of Cenozoic strata in the northern Qaidam Basin remain highly debated. Here, we combine analyses of detrital zircons U Pb geochronology for recent and ancient fluvial sediments from the northern Qaidam Basin to trace source areas of Cenozoic strata and reconstruct related mountain-building processes. The results indicate that the diagnostic 270–240 Ma zircon U Pb peak, which was previously recognized as the unique input of a southern source area, is widespread in the recent fluvial sediments of the northern Qaidam Basin. Given our new zircon U Pb data, the source-to-sink transport processes of Cenozoic sediments in the northern Qaidam Basin can be summarized as follows. (1) The northern Qaidam Basin has received the eroded detrital material from a dominantly northern source throughout the Cenozoic. (2) The Qaidam BeiShan was uplifted already at least by the early Eocene and served as the single contributor of detritus to the Dahonggou (DHG) region, suggesting that far-field stress due to the India-Asia collision had been propagated to this region as early as the early Eocene. (3) An abrupt change in provenance is observed in the DHG region during 46.5–43.7 Ma. We interpret this middle Eocene source change as reflecting the onset of growth of the North Altyn Tagh Range, implying that the North Altyn Tagh Range was already serving as an important source area for the DHG region by the middle Eocene. (4) The South Qilian Range served again as the dominant source area for the DHG region after 24.6 Ma. The shift in provenance from the North Altyn Tagh Range to the South Qilian Range can be attributed to the uplift of the Saishiteng Shan.

Weihong He, G.R. Shi, Yang Zhang, Tinglu Yang, Fei Teng.& Shunbao Wu, December 2012. Systematics and palaeoecology of Changhsingian (Late Permian) Ambocoeliidae brachiopods from South China and implications for the end-Permian mass extinction. Alcheringa 36, 515–530. ISSN 0311-5518. Four Ambocoeliidae brachiopod species including one new species (Crurithyris tazawai sp. nov., Crurithyris sp., Paracrurithyris pygmaea and Attenuatella mengi) are described from the Changhsingian (Late Permian) deep-water facies of South China. Analysis of the morphology, palaeoecology and palaeogeographical and temporal distributions of these species revealed that the presence of a delthyrium and/or the micro-ornaments among three of the four species (Crurithyris tazawai sp. nov., Paracrurithyris pygmaea and Attenuatella mengi) favoured an epifaunal (epiphytic) lifestyle. Morphological differences suggest that Paracrurithyris pygmaea may have been more effective metabolically in forming the shell compared with Attenuatella m...

Herein we introduce a novel strategy based on capillary force lithography (CFL) to fabricate asymmetric polymeric ring structures by applying both shear and nomal forces to a poly(dimethylsiloxane) stamp. The mechanism for the formation of asymmetric rings is caused by the deflection of cylindrical PDMS pillars due to the shear load, which is therefore termed deflected CFL (dCFL). The asymmetric polymeric rings could be readily transferred to an underlying gold layer to generate split ring structures with tunable opening angles. Asymmetric structures based upon trigular and square-shaped pillars were also fabricated. These elements were formed into periodic arrays over surface areas as large as 1 cm(2) and may have optical and electromagnetic applications.

An electrophoretic-electroosmotic focusing (EEF) method was developed and used to separate membrane-bound proteins and charged lipids based on their charge-to-size ratio from an initially homogeneous mixture. EEF uses opposing electrophoretic and electroosmotic forces to focus and separate proteins and lipids into narrow bands on supported lipid bilayers (SLBs). Membrane-associated species were focused into specific positions within the SLB in a highly repeatable fashion. The steady-state focusing positions of the proteins could be predicted and controlled by tuning experimental conditions, such as buffer pH, ionic strength, electric field, and temperature. Careful tuning of the variables should enable one to separate mixtures of membrane proteins with only subtle differences. The EEF technique was found to be an effective way to separate protein mixtures with low initial concentrations, and it overcame diffusive peak broadening to allow four bands to be separated simultaneously within a 380 μm wide isolated supported membrane patch.

We report the effects of ligand presentation on the binding of aqueous proteins to solid supported lipid bilayers. Specifically, we show that the equilibrium dissociation constant can be strongly affected by ligand lipophilicity and linker length/structure. The apparent equilibrium dissociation constants (K(D)) were compared for two model systems, biotin/anti-biotin and 2,4-dinitrophenyl (DNP)/anti-DNP, in bulk solution and at model membrane surfaces. The binding constants in solution were obtained from fluorescence anisotropy measurements. The surface binding constants were determined by microfluidic techniques in conjunction with total internal reflection fluorescence microscopy. The results showed that the bulk solution equilibrium dissociation constants for anti-biotin and anti-DNP were almost identical, K(D)(bulk) = 1.7 +/- 0.2 nM vs. 2.9 +/- 0.1 nM. By contrast, the dissociation constant for anti-biotin antibody was three orders of magnitude tighter than for anti-DNP at a lipid membrane interface, K(D) = 3.6 +/- 1.1 nM vs. 2.0 +/- 0.2 microM. We postulate that the pronounced difference in surface binding constants for these two similar antibodies is due to differences in the ligands' relative lipophilicity, i.e., the more hydrophobic DNP molecules had a stronger interaction with the lipid bilayers, rendering them less available to incoming anti-DNP antibodies compared with the biotin/anti-biotin system. However, when membrane-bound biotin ligands were well screened by a poly(ethylene glycol) (PEG) polymer brush, the K(D) value for the anti-biotin antibody could also be weakened by three orders of magnitude, 2.4 +/- 1.1 microM. On the other hand, the dissociation constant for anti-DNP antibodies at a lipid interface could be significantly enhanced when DNP haptens were tethered to the end of very long hydrophilic PEG lipopolymers (K(D) = 21 +/- 10 nM) rather than presented on short lipid-conjugated tethers. These results demonstrate that ligand presentation strongly influences protein interactions with membrane-bound ligands.

We investigated specific ion effects on interfacial water structure next to macromolecules with vibrational sum frequency spectroscopy (VSFS). Poly-(N-isopropylacrylamide) was adsorbed at the air/water interface for this purpose. It was found that the presence of salt in the subphase could induce the reorganization of water adjacent to the macromolecule and that the changes depended greatly on the specific identity and concentration of the salt employed. Ranked by their propensity to orient interfacial water molecules, sodium salts could be placed in the following order: NaSCN > NaClO4 > NaI > NaNO3 approximately NaBr > NaCl > pure water approximately NaF approximately Na2SO4. This ordering is a Hofmeister series. On the other hand, varying the identity of the cation exhibited virtually no effect. We also showed that the oscillator strength in the OH stretch region was linearly related to changes in the surface potential caused by anion adsorption. This fact allowed binding isotherms to be abstracted from the VSFS data. Such results offer direct evidence that interfacial water structure can be predominantly the consequence of macromolecule-ion interactions.

Herein, we developed a new separation-based detection method that is capable of simultaneously identifying multiple competitively binding proteins for the same ligand on supported lipid bilayers (SLBs). This strategy used unlabeled target analyte proteins that bind to fluorescently tagged, lipid-conjugated ligands within the SLB. The protein-ligand binding complexes were then focused under an applied potential to different locations within the SLB based on each protein's size and charge. Both protein identity and relative surface concentration information could be obtained, simultaneously. Specifically, the competitive binding of streptavidin and goat anti-biotin for biotin-conjugated lipids was explored. It was found that streptavidin could inhibit the binding of goat anti-biotin antibodies for biotin-cap-1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(7-nitro-2-1,3-benzoxadiazol-4-yl)(biotin-cap-NBD-PE) lipids and that streptavidin more effectively outcompeted the anti-biotin antibody at lower protein concentrations. Also, modulating the chemical composition of the membrane helped control the ultimate focusing position and separation of the streptavidin-bound biotin, anti-biotin-bound biotin, and free biotin-conjugated lipid bands. The assay developed herein provides a simple and convenient strategy for simultaneously monitoring target analytes that bind to the identical ligand and may ultimately be useful in developing assays that help overcome problems associated with cross-reactivity.

Yang, T.L., He, W.H., Zhang, K.X., Wu, S.B., Zhang, Y., Yue, M.L., Wu, H.T. & Xiao, Y.F., XX.XXXX.2015. Palaeoecological insights into the Changhsingian–Induan (latest Permian–earliest Triassic) bivalve fauna at Dongpan, southern Guangxi, South China. Alcheringa 40, xxx–xxx. ISSN 0311-5518.The Talung Formation (latest Permian) and basal part of Luolou Formation (earliest Triassic) of the Dongpan section have yielded 30 bivalve species in 17 genera. Eight genera incorporating 11 species are systematically described herein, including three new species: Nuculopsis guangxiensis, Parallelodon changhsingensis and Palaeolima fangi. Two assemblages are recognized, i.e., the Hunanopecten exilis–Euchondria fusuiensis assemblage from the Talung Formation and the Claraia dieneri–Claraia griesbachi assemblage from the Luolou Formation. The former is characterized by abundant Euchondria fusuiensis, an endemic species, associated with other common genera, such as Hunanopecten, which make it unique from coeval assemblages of South China. A palaeoecological analysis indicates that the Changhsingian bivalve assemblage at Dongpan is diverse and represented by various life habits characteristic of a complex ecosystem. This also suggests that redox conditions were oxic to suboxic in deep marine environments of the southernmost Yangtze Basin during the late Changhsingian, although several episodes of anoxic perturbations and declines in palaeoproductivity saw deterioratation of local habitats and altered the taxonomic composition or population size of the bivalve fauna.Tinglu Yang [yang@geology.so], School of Earth Sciences, China University of Geosciences, 388 Lumo Road, Hongshan, Wuhan 430074, PR China; Weihong He* [whzhang@cug.edu.cn] and Kexin Zhang [kx_zhang@cug.edu.cn], State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, 388 Lumo Road, Hongshan, Wuhan 430074, PR China; Shunbao Wu [shbwu@cug.edu.cn], Yang Zhang [zhangy05@163.com], Mingliang Yue [812182779@qq.com], Huiting Wu [ht_wu415@163.com] and Yifan Xiao [shadowyi@sohu.com], School of Earth Sciences, China University of Geosciences, 388 Lumo Road, Hongshan, Wuhan 430074, PR China.

The fabrication of metal nanoparticles has drawn considerable attention because of both fundamental interest and the potential for applications. Depending on the exact particle size to be synthesized, elaborate and often time-consuming processes can be required to achieve highly uniform particles. Herein, we demonstrate a simple, inexpensive, and rapid method for making metal nanoparticles ranging between 10 and 100 nm in size. The process can be competed in approximately 11 min without the use of a clean-room environment or vacuum techniques. The method works by using a thin supported TiO2 film as a photocatalyst and an alumina membrane as a template. The nanoparticle array formed in this manner is nearly monodisperse and the particle surface density and geometry are uniform over large areas. The templates are reusable and the technique may be amenable for biosensing as well as catalytic applications. Metal nanoparticles possess unique physical, magnetic, optical, electrical, and catalytic properties. Gaining control over their size and geometry during the fabrication process is of central interest. This has led to remarkable achievements in the preparation of nearly monodisperse particles up to approximately 10 nm in diameter by employing synthetic methods. Moreover, photolithographic methods now make it possible to precisely control geometries down to the 100 nm scale. There are, however, fewer methods for easily fabricating highly uniform metal nanoparticle arrays on an intermediate length scale. Previous fabrication efforts on the 10 to 100 nm scale have included reduction synthesis and nanolithography. Also, template approaches have been used to synthesize nanotubes, nanorods, nanoelectrodes, and nanoparticles. Some of these techniques depend on wet electrochemical methods to deposit metal onto a uniform nanoporous template, while others apply thermal or electron-beam evaporation followed by etching procedures. Anodic aluminum oxide (AAO) templating has been widely exploited in these applications because of its uniformity, rigidity, and size-controllable properties. It should be noted that the approaches described above require a vacuum chamber for evaporating metal, a clean-room environment, sophisticated preparation, relatively specialized equipment, and/or etching steps. It was therefore deemed desirable to design a bench-top technique that could be performed rapidly with minimal equipment and without specialized facilities, while still achieving large arrays of highly uniform particles. Herein, a simple templating method is described for photoreducing metal from aqueous solutions onto TiO2 thin films through a nanoporous filtration membrane. TiO2 has well-studied photocatalytic properties, which makes it an excellent choice for reducing metal ions from solution by UV illumination. Most often it has been used in the form of nanoparticles for reducing metal ions in solution. More recently the process has been demonstrated with a thin TiO2 film on a silica substrate. [40] In both cases the metal particles that are synthesized are typically 50 to 200 nm, where the average size can be tuned to some extent by the solution conditions. Although the particles are not monodispersed, it should be emphasized that the process can be performed under mild conditions (i.e., at room temperature in aqueous solution and neutral pH). Our strategy for forming uniform size arrays of metal nanoparticles is outlined in Figure 1. In the first step, a TiO2 precursor was deposited onto the surface of a Pyrex slide in a dropwise fashion from an alcohol solution. The precursor solution consisted of 1 g of titanium(IV) isopropoxide, 0.15 g of HCl, and 8.0 g of isopropyl alcohol. Approximately 150 lL of this mixture quickly and completely wetted the surface of a 2.5 cm × 2.5 cm planar Pyrex substrate. Next, a circular nanoporous alumina filtration membrane with 18 nm diameter pores was placed on top of the wet glass slide and the system was allowed to dry under ambient conditions for 6 min. As the isopropyl alcohol evaporated, the TiO2 film formed spontaneously on the Pyrex and its presence was directly verified using X-ray photoelectron spectroscopy (XPS). Profilometry measurements showed that the film was approximately 200 nm thick. Atomic force microscopy (AFM) measurements revealed that the coating was very flat with a rootmean-square roughness of 0.72 nm over a 1 lm × 1 lm area (Fig. 2a). This surface roughness was identical to a control experiment where the precursor solution was allowed to evaporate from the substrate in the absence of the alumina membrane. Indeed, no evidence of TiO2 pillar formation caused by the nanoporous template could be detected. Moreover, only trace amounts of TiO2 could be found on the alumina surface using XPS. It should be noted that the alumina template was C O M M U N IC A TI O N S

The adsorption of large unilamellar vesicles composed of various combinations of phosphatidylcholine, phosphatidylethanolamine (PE), monomethyl PE, and dimethyl PE (PE-Me2) onto a glass surface was studied using fluorescence microscopy. The average lipid geometry within the vesicles, described mathematically by the average intrinsic curvature, C(0,ave), was methodically altered by changing the lipid ratios to determine the effect of intrinsic curvature on the ability of vesicles to rupture and form a supported lipid bilayer. We show that the ability of vesicles to create fluid planar bilayers is dependent on C(0,ave) and independent of the identity of the component lipids. When the C(0,ave) was approximately -0.1 nm(-1), the vesicles readily formed supported lipid bilayers with almost full mobility. In contrast, when the C(0,ave) ranged from approximately -0.2 to approximately -0.3 nm(-1), the adsorbed vesicles remained intact upon the surface. The results indicate that the average shape of lipid molecules within a vesicle (C(0,ave)) is essential for determining kinetically viable reactions that are responsible for global geometric changes.