Protective copolymers for nonviral gene vectors: synthesis, vector characterization and application in gene delivery

Uncontrolled interactions of gene vectors and drug carriers in and with an in vivo environment pose serious limitations to their applicability. In order to reduce such interactions we have designed, synthesized and applied novel copolymers of poly(ethylene glycol) and reactive linkers which are derivatized with anionic peptides after copolymerization. The anionic copolymer derivatives are used to coat positively charged nonviral gene vectors by electrostatic interactions. The copolymer coat confers to polyelectrolyte colloids of DNA and polycations steric stabilization in their minimal size and prevents salt- and serum albumin-induced aggregation. Furthermore, complement activation and the interaction with serum proteins are drastically reduced or abolished in contrast to unprotected DNA complexes. The designed vectors are compatible with the intracellular steps of gene delivery and can even enhance transfection efficiency as demonstrated with various adherent and nonadherent cell lines in culture. The synthetic concept is amenable to the principles of combinatorial chemistry and the copolymeric products may be applicable beyond gene delivery in targeted drug delivery

The RESET project: constructing a European tephra lattice for refined synchronisation of environmental and archaeological events during the last c. 100 ka

This paper introduces the aims and scope of the RESET project (. RESponse of humans to abrupt Environmental Transitions), a programme of research funded by the Natural Environment Research Council (UK) between 2008 and 2013; it also provides the context and rationale for papers included in a special volume of Quaternary Science Reviews that report some of the project's findings. RESET examined the chronological and correlation methods employed to establish causal links between the timing of abrupt environmental transitions (AETs) on the one hand, and of human dispersal and development on the other, with a focus on the Middle and Upper Palaeolithic periods. The period of interest is the Last Glacial cycle and the early Holocene (c. 100-8 ka), during which time a number of pronounced AETs occurred. A long-running topic of debate is the degree to which human history in Europe and the Mediterranean region during the Palaeolithic was shaped by these AETs, but this has proved difficult to assess because of poor dating control. In an attempt to move the science forward, RESET examined the potential that tephra isochrons, and in particular non-visible ash layers (cryptotephras), might offer for synchronising palaeo-records with a greater degree of finesse. New tephrostratigraphical data generated by the project augment previously-established tephra frameworks for the region, and underpin a more evolved tephra 'lattice' that links palaeo-records between Greenland, the European mainland, sub-marine sequences in the Mediterranean and North Africa. The paper also outlines the significance of other contributions to this special volume: collectively, these illustrate how the lattice was constructed, how it links with cognate tephra research in Europe and elsewhere, and how the evidence of tephra isochrons is beginning to challenge long-held views about the impacts of environmental change on humans during the Palaeolithic. © 2015 Elsevier Ltd.RESET was funded through Consortium Grants awarded by the Natural Environment Research Council, UK, to a collaborating team drawn from four institutions: Royal Holloway University of London (grant reference NE/E015905/1), the Natural History Museum, London (NE/E015913/1), Oxford University (NE/E015670/1) and the University of Southampton, including the National Oceanography Centre (NE/01531X/1). The authors also wish to record their deep gratitude to four members of the scientific community who formed a consultative advisory panel during the lifetime of the RESET project: Professor Barbara Wohlfarth (Stockholm University), Professor Jørgen Peder Steffensen (Niels Bohr Institute, Copenhagen), Dr. Martin Street (Romisch-Germanisches Zentralmuseum, Neuwied) and Professor Clive Oppenheimer (Cambridge University). They provided excellent advice at key stages of the work, which we greatly valued. We also thank Jenny Kynaston (Geography Department, Royal Holloway) for construction of several of the figures in this paper, and Debbie Barrett (Elsevier) and Colin Murray Wallace (Editor-in-Chief, QSR) for their considerable assistance in the production of this special volume.Peer Reviewe

Holocene-scale fire dynamics of central European temperate sprucebeech forests

This study investigated the long-term role and drivers of fire in the central European temperate sprucebeech forests from Prášilské Jezero, Czech Republic. The results illustrate the complex relationship between broad-scale climate, vegetation composition, and local human activities on fire throughout the Holocene. Biomass burning was the highest (average 3 fires/1000 years) and most severe during the early Holocene when fire resistant taxa (Pinus, Corylus and Betula) dominated. Using a Generalized Additive Model to assess the response of dominant canopy taxa to changes in biomass burning and fire severity, response curves demonstrate a positive relationship (p < 0.01) between fire resistant taxa and increases in biomass burning. Norway spruce (Picea abies) established ~10,000 cal yr BP and expanded during peak biomass burning. Response curves show a slight negative relationship with Picea and increasing biomass burning, and a positive relationship with increasing fire severity. This suggests that central European spruce forests may not be significantly impacted by fire. Regional biomass burning dramatically decreased with the expansion of fire sensitive taxa (e.g. Fagus sylvatica) ~6500 cal yr BP, yet no dramatic reduction in local fire frequency occurred. This suggests either human activities or rare fire-promoting climatic events were important in shaping local fire regimes. Fire activity peaked (6 fires/1000 years) ~2500 cal yr BP and paralleled increases in anthropogenic pollen indicators. Fagus response curves illustrates a negative (p < 0.01) relationship with increasing biomass burning and fire severity suggesting that natural Fagus forests may be increasingly vulnerable to projected increases in wildfire occurrence

Exploring the Ecological History of a Tropical Agroforestry Landscape Using Fossil Pollen and Charcoal Analysis from Four Sites in Western Ghats, India

Contrary to expectations, some human-modified landscapes are considered to sustain both human activities and biodiversity over the long-term. Agroforestry systems are among these landscapes where crops are planted under native shade trees. In this context, ancient agroforestry systems can provide insight into how farmers managed the landscape over time. Such insight can help to quantify the extent to which tropical forests (especially habitat-specialist trees) are responding to local and landscape-level management. Here, we extracted fossil pollen (indicator of past vegetation changes) and macroscopic charcoal (indicator of biomass burning) from four forest hollows’ sedimentary sequences in an ancient agroforestry system in Western Ghats, India. We used a mixed-modelling approach and a principal components analysis (PCA) to determine past trajectories of forest change and species composition dynamics for the last 900 years. In addition, we reconstructed the long-term forest canopy dynamics and examined the persistence of habitat-specialist trees over time. Our results show that the four sites diverged to a surprising degree in both taxa composition and dynamics. However, despite these differences, forest has persisted over 900 years under agricultural activities within agroforestry systems. This long-term analysis highlights the importance of different land-use legacies as a framework to increase the effectiveness of management across tropical agricultural lands

Local Application of BMP-2 Specific Plasmids in Fibrin Glue does not Promote Implant Fixation

<p>Abstract</p> <p>Background</p> <p>BMP-2 is known to accelerate fracture healing and might also enhance osseointegration and implant fixation. Application of recombinant BMP-2 has a time-limited effect. Therefore, a gene transfer approach with a steady production of BMP-2 appears to be attractive. The aim of this study was to examine the effect of locally applied BMP-2 plasmids on the bone-implant integration in a non-weight bearing rabbit tibia model using a comparatively new non-viral copolymer-protected gene vector (COPROG).</p> <p>Methods</p> <p>Sixty rabbits were divided into 4 groups. All of them received nailing of both tibiae. The verum group had the nails inserted with the COPROG vector and BMP-2 plasmids using fibrin glue as a carrier. Controls were a group with fibrin glue only and a blank group. After 28 and 56 days, these three groups were sacrificed and one tibia was randomly chosen for biomechanical testing, while the other tibia underwent histomorphometrical examination. In a fourth group, a reporter-gene was incorporated in the fibrin glue instead of the BMP-2 formula to prove that transfection was successful.</p> <p>Results</p> <p>Implant fixation strength was significantly lower after 28 and 56 days in the verum group. Histomorphometry supported the findings after 28 days, showing less bone-implant contact.</p> <p>In the fourth group, successful transfection could be confirmed by detection of the reporter-gene in 20 of 22 tibiae. But, also systemic reporter-gene expression was found in heterotopic locations, showing an undesired spreading of the locally applied gene formula.</p> <p>Conclusion</p> <p>Our results underline the transfecting capability of this vector and support the idea that BMP-2 might diminish osseointegration. Further studies are necessary to specify the exact mechanisms and the systemic effects.</p

Quaternary glacial history of the Mediterranean mountains

Glacial and periglacial landforms are widespread in the mountains of the Mediterranean region. The evidence for glacial and periglacial activity has been studied for over 120 years and it is possible to identify three phases of development in this area of research. First, a pioneer phase characterized by initial descriptive observations of glacial landforms; second, a mapping phase whereby the detailed distribution of glacial landforms and sediments have been depicted on geomorphological maps; and, third, an advanced phase characterized by detailed understanding of the geochronology of glacial sequences using radiometric dating alongside detailed sedimentological and stratigraphical analyses. It is only relatively recently that studies of glaciated mountain terrains in the Mediterranean region have reached an advanced phase and it is now clear from radiometric dating programmes that the Mediterranean mountains have been glaciated during multiple glacial cycles. The most extensive phases of glaciation appear to have occurred during the Middle Pleistocene. This represents a major shift from earlier work whereby many glacial sequences were assumed to have formed during the last cold stage. Glacial and periglacial deposits from multiple Quaternary cold stages constitute a valuable palaeoclimatic record. This is especially so in the Mediterranean mountains, since mountain glaciers in this latitudinal zone would have been particularly sensitive to changes in the global climate system. © 2006 Edward Arnold (Publishers) Ltd

Cyanobacteria of the thermal spring at Pancharevo, Sofia, Bulgaria

Eight taxa of cyanobacteria were identified in the thermal spring at Pancharevo (in the Sofia basin, Bulgaria). As well as the widespread Lyngbya thermalis, Phormidesmis molle (syn. Phormidium molle), Phormidium papyraceum, Phormidium corium and Mastigocladus laminosus, four species were identified for the first time in Bulgaria: Calothrix thermalis, Gloeocapsa gelatinosa, Leibleinia epiphytica and Symploca thermalis

How many is enough? Determining optimal count totals for ecological and palaeoecological studies of testate amoebae

Testate amoebae are increasingly used in ecological and palaeoecological studies of wetlands. To characterise the amoeba community a certain number of individuals need to be counted under the microscope. To date, most studies have aimed for 150 individuals, but that sample size is not based on adequate evidence. When testate amoeba concentrations are low, it can be difficult or impossible to reach this total. The impacts of lower count totals have never been seriously scrutinised. We investigated the impact of count size on number of taxa identified, quantitative inferences of environmental variables and the strength of the links between amoebae and environmental data in the context of predicting depth to water table. Low counts were simulated by random selection of individuals from four existing datasets. Results show progressively diminishing returns by all criteria as count size increases from low numbers to counts of 150. A higher count is required to identify all taxa than to adequately characterise the community for transfer function inference. We suggest that in most cases, it will be a more efficient use of time to count a greater number of samples to a lower count. While a count of 50 individuals may be sufficient for some samples from some sites we recommend that counts of 100 individuals should be sufficient for most samples. Counts need only be increased to 150 or more where the aim is to identify relatively minor, but still potentially ecologically relevant community changes. This approach will help reduce lack of replication and low resolution, which are common limitations in testate amoeba-based palaeoecological and ecological studies