Inert Structures Research Articles

Kinetic Control of Complexity in Multiple Dynamic Libraries

AbstractMultiple dynamic libraries of compounds are generated when more than one reversible reaction comes into play. Commonly, two or more orthogonal reversible reactions are used, leading to non‐communicating dynamic libraries which share no building blocks. Only a few examples of communicating libraries have been reported, and in all those cases, building blocks are reversibly exchanged from one library to the other, constituting an antiparallel dynamic covalent system. Herein we report that communication between two different dynamic libraries through an irreversible process is also possible. Indeed, alkyl amines cancel the dynamic regime on the nucleophilic substitution of tetrazines, generating kinetically inert compounds. Interestingly, such amine can be part of another dynamic library, an imine‐amine exchange. Thus, both libraries are interconnected with each other by an irreversible process which leads to kinetically inert structures that contain parts from both libraries, causing a collapse of the complexity. Additionally, a latent irreversible intercommunication could be developed. In such a way, a stable molecular system with specific host–guest and fluorescence properties, could be irreversibly transformed when the right stimulus was applied, triggering the cancellation of the original supramolecular and luminescent properties and the emergence of new ones.

Kinetic Control of Complexity in Multiple Dynamic Libraries.

Multiple dynamic libraries of compounds are generated when more than one reversible reaction comes into play. Commonly, two or more orthogonal reversible reactions are used, leading to non-communicating dynamic libraries which share no building blocks. Only a few examples of communicating libraries have been reported, and in all those cases, building blocks are reversibly exchanged from one library to the other, constituting an antiparallel dynamic covalent system. Herein we report that communication between two different dynamic libraries through an irreversible process is also possible. Indeed, alkyl amines cancel the dynamic regime on the nucleophilic substitution of tetrazines, generating kinetically inert compounds. Interestingly, such amine can be part of another dynamic library, an imine-amine exchange. Thus, both libraries are interconnected with each other by an irreversible process which leads to kinetically inert structures that contain parts from both libraries, causing a collapse of the complexity. Additionally, a latent irreversible intercommunication could be developed. In such a way, a stable molecular system with specific host-guest and fluorescence properties, could be irreversibly transformed when the right stimulus was applied, triggering the cancellation of the original supramolecular and luminescent properties and the emergence of new ones.

Curcumin coating: a novel solution to mitigate inherent carbon nanotube toxicity

Multi-walled Carbon Nanotubes (MWCNTs) are inert structures with high aspect ratios that are widely used as vehicles for targeted drug delivery in cancer and many other diseases. They are largely non-toxic in nature however, when cells are exposed to these nanotubes for prolonged durations or at high concentrations, they show certain adverse effects. These include cytotoxicity, inflammation, generation of oxidative stress, and genotoxicity among others. To combat such adverse effects, various moieties can be attached to the surface of these nanotubes. Curcumin is a known anti-inflammatory, antioxidant and cytoprotective compound derived from a medicinal plant called Curcuma longa. In this study, we have synthesized and characterized Curcumin coated-lysine functionalized MWCNTs and further evaluated the cytoprotective, anti-inflammatory, antioxidant and antiapoptotic effect of Curcumin coating on the surface of MWCNTs. The results show a significant decrease in the level of inflammatory molecules like IL-6, IL-8, IL-1β, TNFα and NFκB in cells exposed to Curcumin-coated MWCNTs as compared to the uncoated ones at both transcript and protein levels. Further, compared to the uncoated samples, there is a reduction in ROS production and upregulation of antioxidant enzyme-Catalase in the cells treated with Curcumin-coated MWCNTs. Curcumin coating also helped in recovery of mitochondrial membrane potential in the cells exposed to MWCNTs. Lastly, cells exposed to Curcumin-coated MWCNTs showed reduced cell death as compared to the ones exposed to uncoated MWCNTs. Our findings suggest that coating of Curcumin on the surface of MWCNTs reduces its ability to cause inflammation, oxidative stress, and cell death.Graphical (a) Synthesis of Curcumin-coated-Lysine-functionalized MWCNTs. (b) Flow of research depicting experimental groups and studies performed along with the underlying techniques used.

SOIL ENGINEERING: MODERN CHALLENGES AND DEVELOPMENT PROSPECTS

The emergence of private ownership of land and the urgent needs of the developing practice of land use require a rethinking of some existing fundamental paradigms and the search for new technologies in the relationship between man and nature, as well as, for this purpose, the creation of new sections of knowledge. New ways of developing the surrounding landscape environment are not enough and the methods offered by traditional disciplines. Construction norms and rules need to be clarified for anthropogenically modified soils and soils. Soil engineering is a field of knowledge that studies the engineering properties of the soil and the possibility of using them for the design and construction of soilengineering structures in the soil and soil structures designed to solve specifi c soilengineering problems of environmental management and develop environmentally friendly engineering technologies for managing the properties of soils and landscapes. Such technologies are in urgent demand today in lowrise, communal, landscape, landscape gardening, agricultural, hydrological, forestry, urban, etc., construction. The objects of soil engineering are soilengineering structures and soil structures of various scales (from pedon to soil cover) created in natural and anthropogenically modified soils. Soilengineering structures mean a soil-technical complex that preserves or creates the basis for the sustainable existence of the natural environment. All soilengineering structures can be divided into inert structures (foundations, pipelines, road surfaces) and structures interacting with the soil (wells, fi ltrationfields, reservoirs, drainage and irrigation systems). Soil and landscape engineering is an integral part of environmental engineering, which is rapidly developing. Technologies of soil and landscape engineering have been one of the main driving forces of the progress of civilization throughout the existence of humanity, and they reached their peak in the Russian estate culture of the 19th century. However, the new socioeconomic phenomenon the «modern Russian estate» needs to be studied and norms and rules developed for organizing its interaction with the natural environment, which in many respects is similar to the influence of garden construction and is very similar to the influence of a city in space and time.

High performance mass spectrometry reveals possible kerogen substructures in persistent ancient human brain

The recovery of visually recognizable brain masses from skeletonized human burials is rare; the discovery of an exceptionally well-preserved 2500-year-old brain during excavations at Heslington, Yorkshire, UK, therefore attracted international publicity. Analysis of a lipidic extract of that brain material showed the presence of high molecular weight organic components. To determine whether the presence of such compounds is a common feature of unusually preserved brain specimens, we have carried out high resolution matrix-assisted laser desorption/ionization Fourier transform ion-cyclotron resonance mass spectrometric (MALDI FT-ICR-MS) analyses of lipidic extracts of preserved brain remains from 14 contexts, obtained from four archaeological sites ranging from 200 to 2500 years old. These data allowed elemental formulae for the predominant signals in the resulting spectra to be generated, and a detailed comparison of the resulting very rich dataset was carried out, allowing 38 molecular formulae to be assigned. The components identified across all the sample extracts analysed fell into the same class of large organic molecules as those from the Heslington brain and are generally functionalized with low numbers of heteroatoms (oxygen, nitrogen, or both). These components do not correspond to those identified in adipocere, but instead resemble kerogen substructures, surprisingly formed over historic rather than geological timescales. The presence of such insoluble, inert structures would help explain why brain material in which they are found is persistent. Our results pave the way for further analyses aimed at understanding the processes that take place when brain material is preserved in the archaeological record.

Break to Build: Isothermal Assembly of Nucleic Acid Nanoparticles (NANPs) via Enzymatic Degradation.

The intrinsic properties of RNA and DNA biopolymers emphasized by engineered nucleic acid nanoparticles (NANPs) offer accelerated development of next-generation therapies. The rational design of NANPs facilitates programmable architectures intended for regulated molecular and cellular interactions. The conventional bottom-up assembly of NANPs relies on the thermal annealing of individual strands. Here, we introduce a concept of nuclease-driven production of NANPs where selective digestion of functionally inert structures leads to isothermal self-assembly of liberated constituents. The working principles, morphological changes, assembly kinetics, and the retention of structural integrity for system components subjected to anhydrous processing and storage are assessed. We show that the assembly of precursors into a single structure improves stoichiometry and enhances the functionality of nuclease-driven products. Furthermore, the experiments with immune reporting cell lines show that the developed protocols retain the immunostimulatory functionality of tested NANPs. The presented approach enables exploitation of the advantages of conditionally produced NANPs and demonstrates that NANPs' stability, immunorecognition, and assembly can be regulated to allow for a more robust functional system.

Influence of doping Fe on performance of calcium-based doped materials for thermochemical energy storage: A DFT study

In this paper, the optical and thermodynamic properties of Fe-doped Ca-based materials were revealed by the Density Functional Theory method. The results showed that the doped Fe atom was oxidized by O2− to form inert structures, enhancing the resistance of CaO to sintering at high temperatures. More importantly, the doping of Fe enabled the electrons to jump between energy levels more easily, improving the light absorption ability of Ca-based composites. Meanwhile, a qualitative analysis of the thermodynamic parameters of the composites was carried out. It was found that the thermal conductivity and specific heat capacity of the composites decreased with increasing iron content, while the Debye temperature increased. Besides, the doping of Fe leads to the reduction of activation energy of the reaction due to the formation of electron-deficient O sites on the surface, resulting in a suppression of the reaction rate between CaO and CO2.

Superior peroxidase mimetic activity induced by topological surface states of Weyl semimetal WTe2

Nanozymes, as promising alternatives that integrate the advantage of natural enzymes and nanomaterials are attracted enormous interest due to their low cost, environmental tolerance, high stability, as well as significant catalytic activity. Two-dimensional materials, transition metal dichalcogenides (TMDs) harbor the potential as peroxidase mimic which is attributed to the active edge sites and surface electron transfer capability. However, a challenge faced in peroxidase mimetic of TMDs is the low catalytic activity which originates from the inert structures. Here, we, for the first time, report that the typical Weyl semimetal WTe2 possesses the superior peroxidase-like performance toward H2O2, which derives from the two-step electron-pathway. We demonstrate a novel functionality of the Weyl semimetal through introducing topologically protected surface states (TSSs) for regulating the electron transfer processes. The underlying mechanism for TSSs promoting enzyme mimetic catalysis is attributed to the effective electron bath provided by the robust TSSs. Experiments and the first-principles calculations show that TSSs of WTe2 which serve as effective electron baths are directly involved in the two-step electron transfer process. In the first step, TSSs accept the electrons donated by the substrate which further enhances the substrate’s absorption. Upon H2O2 adsorption, the electrons are transferred out of TSSs and injected into the absorbed H2O2 orbitals. These findings offer a new linkage between the topological matters with TSSs and nanomaterials for enzyme mimicking.

Lipid Droplets and Their Autophagic Turnover via the Raft-Like Vacuolar Microdomains.

Although once perceived as inert structures that merely serve for lipid storage, lipid droplets (LDs) have proven to be the dynamic organelles that hold many cellular functions. The LDs’ basic structure of a hydrophobic core consisting of neutral lipids and enclosed in a phospholipid monolayer allows for quick lipid accessibility for intracellular energy and membrane production. Whereas formed at the peripheral and perinuclear endoplasmic reticulum, LDs are degraded either in the cytosol by lipolysis or in the vacuoles/lysosomes by autophagy. Autophagy is a regulated breakdown of dysfunctional, damaged, or surplus cellular components. The selective autophagy of LDs is called lipophagy. Here, we review LDs and their degradation by lipophagy in yeast, which proceeds via the micrometer-scale raft-like lipid domains in the vacuolar membrane. These vacuolar microdomains form during nutrient deprivation and facilitate internalization of LDs via the vacuolar membrane invagination and scission. The resultant intra-vacuolar autophagic bodies with LDs inside are broken down by vacuolar lipases and proteases. This type of lipophagy is called microlipophagy as it resembles microautophagy, the type of autophagy when substrates are sequestered right at the surface of a lytic compartment. Yeast microlipophagy via the raft-like vacuolar microdomains is a great model system to study the role of lipid domains in microautophagic pathways.

Experimental Investigation of Reactive-Inert Particulate Matter Detachment from Metal Fibres at Low Flow Velocities and Different Gas Temperatures

The detachment of particle structures from single fibres in gas flow has been investigated only for inert particle structures yet. This study investigates the detachment of particle structures containing reactive components. These reactive components disappear during the reaction and enhance detachment at low flow velocities. Soot was used as the reactive component and glass spheres as the inert component of the particle structure. The soot disappears due to combustion with oxygen leaving only the glass spheres on the fibre. Without reaction, the detachment phenomenon was observed at superficial flow velocities above 1.9 m/s and with reaction at 0.5 m/s. This shows that reacting and disappearing components of the particle structure can enhance detachment.

Improvising urban spaces, inhabiting the in-between

This paper discusses improvisation as a liminal practice of inhabiting the in-between that marks urban spaces from squats and brownfields to communal gardens, from infrastructural maintenance and urban living labs to political protest and solidarity in times of crisis. It shows how improvisation emerges in the interstices between uncertain flux and ossified rigidities to construct in-between spaces of ambiguous political openings even in ostensibly formal, rigid contexts. To that end, it draws on documents, media reports, interviews and participant observation to analyse the multiple mutations of what eventually became the Boris Yeltsin Presidential Centre in Ekaterinburg, a cultural flagship in Russia’s third largest city. Morphed from an abandoned office block into a memorial multi-purpose complex, the Yeltsin Centre is the product of elites and ordinary people responding to conjunctural openings in seemingly inert structures. While highlighting the political openings made possible by improvisation inhabiting the in-between, the paper also underscores the ambiguous nature of this practice and its limits.

CURRENT VIEW CONCERNING MOLECULAR-GENETIC MECHANISMS OF THE INTER-CELLULAR INTERACTION IN THE PROCESS OF OSSEOUS REMODELING

Bones are not inert structures inside the human body; they respond dynamically and with high plasticity to exo- and endogenous factors by changes of their content, structure, characteristics of solidity, etc. This process of skeletal changes known as bone remodeling provides structural integrity of the osseous system and promotes metabolic balance of calcium and phosphorus; remodeling causes resorption of the old or damaged bone followed by the formation of new osseous material. Bone morphogenetic proteins (BMP) constituting a group of morphogenetic signal growth factors (known as cytokines as well) first were described as molecules stimulating formation of the endochondrial osseous tissue. Osteoprotegerin (OPG) is a representative of the super-family of soluble factors to tumor necrosis factor-α (TNF-α) and belongs to secretory low molecular glycoproteins which trans-membrane receptors are located on the surface of osteoblasts, immune cells and precursors of osteoclasts. Transforming growth factor-β1 (TGFβ1) is a representative of cytokines protein in nature, released into the intercellular matrix by the osseous tissue cells and macrophages. It controls a life cycle of cells from the osteoid line, that is, their proliferation, cellular differentiation and functional activity. Sclerostin is produced by osteocytes, mineralized hypertrophic chondrocytes and cementocytes (dental cells) only. It belongs to the components of DAN glycoprotein family (differential screening-selected aberrant genes of neuroblastoma).

The Charge Structures of Aether and Substance

The hypothesis of the charge structures matter serves as the basis for defining the inner energies of “rest” an electron: Ee=αc/(2πRe)[s﹣1]; a neutrino: En=Eeα3; a proton: Ep=Ee(α-2-3α-1). “Relict” radiation is regarded as the wave background is caused by charges oscillations of the aether. Charge pair known as a neutrino is the elementary structure of the aether and participant of the energy and charges exchange reactions between the ethereal and in-ert structures. The internal spin dynamics of the charge structures of particles creates their inertness. The electron mass of “rest” is defined as the time density on its shell that forms the space-time unity: Me=α/(2πRec)[s/m2]. Factors of randomness and periodicity in the radioactivity phenomenon are explained. The ethereal concept of the antiparticles origin is proposed.

Women with late whiplash syndrome have greatly reduced load-bearing of the cervical spine. In-vivo biomechanical, cross-sectional, lateral radiographic study.

No study has been conducted to ascertain whether the load-bearing capacity of the cervical spine is reduced in vivo in late whiplash syndrome (LWS). To compare the segmental cervical angular values across C0-C6, between two conditions: without versus with external axial load upon the head in three groups of women. A single-blind, age-Body Mass Index (BMI) matched, radiographic, cross-sectional study. Radiographic Department at a University Hospital. One hundred eighty-two women, aged between 18-50 years were enrolled. Participants were divided into 3 groups: a group with LWS (N.=62) and two control groups: a chronic insidious neck pain (IONP) group (N.=60) and an asymptomatic group (N.=60). Prior to and on the same day as the radiographic examination took place, BMI in kg/m2 was recorded and all participants answered the Neck Disability Index (NDI). The two symptomatic groups answered also three other pain and disability questionnaires. Analysis of variance (mixed-model ANOVA) for repeated measures was used for comparison. Significant differences between groups, and the two conditions tested was revealed, but only within the asymptomatic and the IONP groups (P<0.0001), but not within the LWS group (P=0.9433). Unexpectedly the women with LWS adopted a rigid horizontal translation strategy when external load was applied upon their head. The inter-rater and intra-rater segmental measurements were highly reliable. Women with LWS scored significantly higher on all questionnaires. The results of this study strongly indicate that the load-bearing capacity of the cervical spine is reduced in vivo in women with LWS. The study shows, for the first time, that the cervical spine in women with LWS predominately functions such as a rigid cylinder when loaded. The study implies that the cervical column is extremely weak in the LWS and that the superficial neck muscles, which are designed to move the head-neck, must compensate and act as rigid stabilizers. This causes great joint reaction forces through the cervical spine and its injured inert structures maintaining the pain and disability, as the results of the questionnaires show.

Interpretation of parameters in strain energy density bone adaptation equation when applied to topology optimization of inert structures

This paper presents structural optimum topologies for a 2D Mitchel type structure, obtained using finite element simulations and the strain energy density theory of bone remodeling, with the space influence function. An interpretation of the parameters in remodeling equation is given, under the purpose of adapting their significance to the topology optimization of inert structures. By neglecting the correlation of the spatial influence function with the trabecular dimensions, a new parameter is introduced that allows for controlling the number of finite elements which locally contribute to the mechanical signal calculation. It is shown that, using this parameter in correlation with the distance attenuation parameter, originally defined in the spatial influence function, similar topologies can be achieved reducing the computational time. Also, the influence of different parameters upon the final topology is discussed. DOI: http://dx.doi.org/10.5755/j01.mech.21.6.12106

Understanding how replication processes can maintain systems away from equilibrium using Algorithmic Information Theory

Replication can be envisaged as a computational process that is able to generate and maintain order far-from-equilibrium. Replication processes, can self-regulate, as the drive to replicate can counter degradation processes that impact on a system. The capability of replicated structures to access high quality energy and eject disorder allows Landauer's principle, in conjunction with Algorithmic Information Theory, to quantify the entropy requirements to maintain a system far-from-equilibrium. Using Landauer's principle, where destabilising processes, operating under the second law of thermodynamics, change the information content or the algorithmic entropy of a system by ΔH bits, replication processes can access order, eject disorder, and counter the change without outside interventions. Both diversity in replicated structures, and the coupling of different replicated systems, increase the ability of the system (or systems) to self-regulate in a changing environment as adaptation processes select those structures that use resources more efficiently. At the level of the structure, as selection processes minimise the information loss, the irreversibility is minimised. While each structure that emerges can be said to be more entropically efficient, as such replicating structures proliferate, the dissipation of the system as a whole is higher than would be the case for inert or simpler structures. While a detailed application to most real systems would be difficult, the approach may well be useful in understanding incremental changes to real systems and provide broad descriptions of system behaviour.

An Endosperm-Associated Cuticle Is Required for Arabidopsis Seed Viability, Dormancy and Early Control of Germination.

Cuticular layers and seeds are prominent plant adaptations to terrestrial life that appeared early and late during plant evolution, respectively. The cuticle is a waterproof film covering plant aerial organs preventing excessive water loss and protecting against biotic and abiotic stresses. Cutin, consisting of crosslinked fatty acid monomers, is the most abundant and studied cuticular component. Seeds are dry, metabolically inert structures promoting plant dispersal by keeping the plant embryo in an arrested protected state. In Arabidopsis thaliana seeds, the embryo is surrounded by a single cell endosperm layer itself surrounded by a seed coat layer, the testa. Whole genome analyses lead us to identify cutin biosynthesis genes as regulatory targets of the phytohormones gibberellins (GA) and abscisic acid (ABA) signaling pathways that control seed germination. Cutin-containing layers are present in seed coats of numerous species, including Arabidopsis, where they regulate permeability to outer compounds. However, the role of cutin in mature seed physiology and germination remains poorly understood. Here we identify in mature seeds a thick cuticular film covering the entire outer surface of the endosperm. This seed cuticle is defective in cutin-deficient bodyguard1 seeds, which is associated with alterations in endospermic permeability. Furthermore, mutants affected in cutin biosynthesis display low seed dormancy and viability levels, which correlates with higher levels of seed lipid oxidative stress. Upon seed imbibition cutin biosynthesis genes are essential to prevent endosperm cellular expansion and testa rupture in response to low GA synthesis. Taken together, our findings suggest that in the course of land plant evolution cuticular structures were co-opted to achieve key physiological seed properties.

Ba/Ca ratios in teeth reveal habitat use patterns of dolphins

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 521:249-263 (2015) - DOI: https://doi.org/10.3354/meps11158 Ba/Ca ratios in teeth reveal habitat use patterns of dolphins S. Botta1,*, C. Albuquerque2, A. A. Hohn3, V. M. F. da Silva4, M. C. O. Santos5, C. Meirelles6, L. Barbosa7, A. P. M. Di Beneditto8, R. M. A. Ramos9, C. Bertozzi10, M. J. Cremer11, V. Franco-Trecu12, N. Miekeley13,†, E. R. Secchi1 1Laboratório de Ecologia e Conservação da Megafauna Marinha - EcoMega, Instituto de Oceanografia, Universidade Federal do Rio Grande, Rio Grande RS 96203-900, Brazil 2Departamento Oceanografia e Limnologia, Universidade Federal do Rio Grande do Norte, Natal 59014-100, RN, Brazil 3National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Beaufort, NC 28516, USA 4Laboratório de Mamíferos Aquáticos, Instituto Nacional de Pesquisas da Amazônia, CP 478, Manaus, AM 69011-790, Brazil 5Departamento de Oceanografia Biológica, Instituto Oceanográfico, Universidade de São Paulo, São Paulo, SP 05508-120, Brazil 6Associação de Pesquisa e Preservação de Ecossistemas Aquáticos - AQUASIS, SESC, Caucaia, CE 61627-010, Brazil 7Organização Consciência Ambiental—ORCA, Vila Velha, ES 29101-315, Brazil 8Universidade Estadual do Norte Fluminense, CBB/LCA, Campos dos Goytacazes, RJ 28013-602, Brazil 9Everest Tecnologia em Serviços Ltda. CP 5074, Vitória, ES 29045-970, Brazil 10Projeto BioPesca, Centro Universitário Monte Serrat, Santos, SP 11015-530, Brazil 11Departamento de Ciências Biológicas, Universidade da Região de Joinville, Joinville, SC 89219-710, Brazil 12Proyecto Franciscana, Sección Etología-Facultad de Ciencias, Iguá 4225, Montevideo, CP 11400, Uruguay 13Departamento de Química, Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro, RJ 22453-900, Brazil *Corresponding author: silbotta@gmail.com†Deceased ABSTRACT: Teeth and otoliths are metabolically inert structures that preserve a chronology of chemical variations that may be related to the environmental histories experienced by each organism. Because of the natural decrease of barium (Ba) and increase of strontium (Sr) bioavailability in water with increasing salinity, these elements may be especially useful to track habitat use in aquatic organisms. Therefore, we tested whether the Ba/Ca and Sr/Ca ratios in the teeth of dolphins represent a salinity gradient. The main aim was to determine whether these elements can be used as a natural tag for different aquatic environments. Teeth from 2 freshwater dolphins (Inia geoffrensis and Sotalia fluviatilis) and 2 marine species (S. guianensis and Pontoporia blainvillei) from Brazil and Uruguay were analyzed using a Laser Ablation Inductively Coupled Plasma-Mass Spectrometer. Intensity ratios of 138Ba/43Ca and 86Sr/43Ca were measured along a line that covered all growth increments in the dentin from the second year of life onwards. Teeth from the freshwater species had mean Ba/Ca values tenfold higher than marine dolphins, confirming the inverse relationship between salinity (and thus ambient Ba/Ca) and elemental ratios in teeth. Furthermore, Ba/Ca ratios could also differentiate dolphins from lower-salinity estuarine areas from those in areas with minimal freshwater discharge. No significant differences were found for Sr/Ca values. Results presented encouraging indications for the application of this technique as a potential new tool for studying habitat use in aquatic mammals. KEY WORDS: Barium · Strontium · Laser ablation ICP-MS · Habitat use · Odontocetes Full text in pdf format PreviousNextCite this article as: Botta S, Albuquerque C, Hohn AA, da Silva VMF and others (2015) Ba/Ca ratios in teeth reveal habitat use patterns of dolphins. Mar Ecol Prog Ser 521:249-263. https://doi.org/10.3354/meps11158 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 521. Online publication date: February 17, 2015 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2015 Inter-Research.

The stress granule protein G3BP1 recruits protein kinase R to promote multiple innate immune antiviral responses.

Stress granules (SGs) are cytoplasmic storage sites containing translationally silenced mRNPs that can be released to resume translation after stress subsides. We previously showed that poliovirus 3C proteinase cleaves the SG-nucleating protein G3BP1, blocking the ability of cells to form SGs late in infection. Many other viruses also target G3BP1 and inhibit SG formation, but the reasons why these functions evolved are unclear. Previously, we also showed a link between G3BP1-induced SGs and protein kinase R (PKR)-mediated translational control, but the mechanism of PKR interplay with SG and the antiviral consequences are unknown. Here, we show that G3BP1 exhibits antiviral activity against several enteroviruses, whereas truncated G3BP1 that cannot form SGs does not. G3BP1-induced SGs are linked to activation of innate immune transcriptional responses through NF-κB and JNK. The G3BP1-induced SGs also recruit PKR and other antiviral proteins. We show that the PXXP domain within G3BP1 is essential for the recruitment of PKR to SGs, for eIF2α phosphorylation driven by PKR, and for nucleating SGs of normal composition. We also show that deletion of the PXXP domain in G3BP1 compromises its antiviral activity. These findings tie PKR activation to its recruitment to SGs by G3BP1 and indicate that G3BP1 promotes innate immune responses at both the transcriptional and translational levels and integrates cellular stress responses and innate immunity. Stress granules appear during virus infection, and their importance is not well understood. Previously, it was assumed that they were nonfunctional artifacts associated with cellular stress. PKR is a well-known antiviral protein; however, its regulation in cells is not well understood. Our work links cellular stress granules with activation of PKR and other innate immune pathways through the activity of G3BP1, a critical stress granule component. The ability of stress granules and G3BP1 to activate PKR and other innate immune transcriptional responses indicates that G3BP1 is an antiviral protein. This work helps to refine a longstanding paradigm indicating stress granules are inert structures and explains why G3BP1 is subverted by many viruses to promote a productive infection.

Limited integrative repair capacity of native cartilage autografts within cartilage defects in a sheep model.

The purpose of this study was to investigate integration and cellular outgrowth of native cartilage autografts transplanted into articular cartilage defects. Native cartilage autografts were applied into chondral defects in the femoral condyle of adult sheep. Within the defects, the calcified cartilage layer was either left intact or perforated to induce bone marrow stimulation. Empty defects served as controls. The joints were analyzed after 6 and 26 weeks by macroscopic and histological analysis using the ICRS II Score and Modified O'Driscoll Scores. Non-treated defects did not show any endogenous regenerative response and bone marrow stimulation induced fibrous repair tissue. Transplanted native cartilage grafts only insufficiently integrated with the defect borders. Cell death and loss of proteoglycans were present at the margins of the grafts at 6 weeks, which was only partially restored at 26 weeks. Significant cellular outgrowth from the grafts or defect borders could not be observed. Bonding of the grafts could be improved by additional bone marrow stimulation providing ingrowing cells that formed a fibrous interface predominantly composed of type I collagen. Transplanted native cartilage grafts remain as inert structures within cartilage defects and fail to induce integrative cartilage repair which rather demands additional cells provided by additional bone marrow stimulation.