Property entitlements and land reform in upland Thai catchments

Issues involved in processes of land reform in degraded upland catchment areas in Thailand include property entitlements over local resource complexes, and the roles of local communities in relation to State agency and commercial stakeholders. An inquiry into collaborative action between stakeholders in an upland Thai catchment has been used as an example of the process of defining property entitlements to the bundles of opportunities for management. This paper draws upon recent conceptual advances concerning property entitlements, particularly as these relate to common-pool resources, and the complex bundle of opportunities for collective and collaborative management in upland catchments. A processual view of collective and collaborative action is the way in which interests are expressed as claims and ultimately translated into entitlements which specify rights to streams of benefits, and associated duties, in relation to a particular resource complex. Social and bureaucratic institutions will influence the way in which stakeholders can participate and interact in this process. Soft systems methodology was used as a guide for a process aimed at identifying mutually beneficial improvements in management between village, agency and commercial stakeholders. The collective and collaborative actions which have developed are all cases whereby particular bundles of property entitlements and related duties have been defined through a process of the expression of claims and identification of mutually beneficial arrangements. These have included local collective management of a water supply, partnerships relating to elements of conservation and production within the local agroecosystem, and socially legitimate patronage to support formal protocols of the land reform process. A process of inquiry which supported the identification of legitimate and mutually beneficial actions has resulted in the definition of bundles of property entitlements which specify benefits and duties by particular stakeholders, with respect to particular resource complexes. This process is discussed in terms of the expression of interests and translation into entitlements through partnerships supported by multiple lines of social and bureaucratic legitimation

Cationic Polymers based on Fructose and Galactose Moieties for Nucleic Acids Delivery

Cationic polymers and glycopolymers were synthesised using the RAFT technique. Combining cationic polymers with glycopolymers has great potential in targeted nucleic acid delivery.1,2 However, many obstacles prevent the use of cationic glycopolymers as vectors including low success in nucleic acid delivery and high toxicity of the cationic polymer. This project aims to investigate RAFT synthesis of cationic glycopolymers with galactose or fructose carbohydrates, their binding ability with their specific lectins and with negatively charged nucleic acids. The cationic polymer poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) was synthesised using RAFT polymerisation. The galactose monomer, 2-(2’,3’,4’,6’-tetra-O-acetyl-β-D-galactosyloxy)ethyl methacrylate (AcGalEMA), and the fructose monomer, 1-O-methacryloyl-2,3:4,5-di-O-isopropylidene--D-fructopyranose (1-O-MAiPFru)3, were polymerised with PDMAEMA to form cationic glycopolymers. Chain extension was confirmed using proton nuclear magnetic spectroscopy (NMR) and gel permeation chromatography (GPC). Gel permeation chromatography was also performed to determine the polydispersity index (uniformity) of the polymers. The protected glycopolymer blocks were modified by deacetylation of the galactose block and acid deprotection of the fructose block. Characterisation of the modified cationic glycopolymers was achieved using proton nuclear magnetic spectroscopy for confirmation of deacetylation/deprotection, and dynamic light scattering to determine the sizes of the diblock copolymers. The zeta potential (ionic charge) of the diblock copolymers was recorded. Aggregation assays between the cationic glycopolymers and plant lectins were assessed. The galactose-containing glycopolymers were conjugated with peanut agglutinin lectin and the fructose-containing glycopolymers were conjugated with lectin from Ulex europaeus. The assays were analysed using dynamic light spectroscopy and ultraviolet-visible spectroscopy. Complexation of the cationic glycopolymer with small interfering RNA (siRNA) was accomplished. The size of the resulting polyplex was recorded with dynamic light spectroscopy. The zeta potential was measured and compared to the zeta potential measurement before complexation with siRNA. Results indicated that RAFT polymerisation was successful in producing diblock polymers of controlled weight and uniform size. The cationic glycopolymers were partially successful in deacetylation/deprotection and highly successful in binding to their specific lectins. The cationic glycopolymer complexed with siRNA; however, further research into the appropriate N:P ratio is necessary. In conclusion, RAFT polymerisation is a suitable technique for the synthesis of cationic glycopolymers for use in nucleic acid delivery. The cationic block of the polymer is able to complex with nucleic acids while the glycopolymer block is able to bind to specific lectins. Further research into carbohydrates specific binding and further modifications to increase nucleic acid delivery efficiency would be beneficial

Translating brazilian poetry: a blueprint for a dissenting canon and cross-cultural anthology

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão. Programa de Pós-Graduação em Estudos da TraduçãoEste trabalho parte da investigação do cânone poético brasileiro e o 'cross'-cânone anglo-brasileiro com o objetivo de criar uma nova antologia em inglês de poesia brasileira canônica e contemporânea de 1922 aos tempos atuais. Dessa maneira, examina a formação e os critérios de seleção de antologias em ambas as culturas literárias e analisa estratégias e abordagens para a tradução de poesia. Para concluir, discute três dos poetas e os poemas escolhidos para o projeto, bem como o processo tradutório e o resultado.With the aim of creating a new anthology in English of canonical and contemporary Brazilian poetry from 1922 to the present day, this thesis investigates both the Brazilian poetic canon and the cross-cultural Anglo-Brazilian poetic canon. It examines the formation and selection criteria of anthologies in both literary cultures, and strategies and approaches for poetry translation. Finally it discusses three of the poets and their poems chosen for the project, analyses the translations, and evaluates the finished product

Chemical fidelity of an RNA polymerase ribozyme

The emergence of catalytically active RNA enzymes (ribozymes) is widely believed to have been an important transition in the origin of life. In the context of a likely heterogeneous chemical environment, substrate specificity and selectivity of these primordial enzymes would have been critical for function. Here we have explored the chemical fidelity, i.e. substrate selectivity and specificity for both single and multiple catalytic steps of the Z RNA polymerase ribozyme - a modern day analogue of the primordial RNA replicase. Using a wide range of nucleotide analogues and ionic conditions, we observe strong energetic but weak geometric discrimination at the incorporation step, indicative of an open active site. In contrast, stringent selectivity is exerted at the extension steps through specific down and upstream interactions with the 3’-terminal nucleoside as well as nascent product and template strands. Our results indicate specificity mechanisms that are found in functionally analogous forms in natural polymerases. They also reveal a level of chemical fidelity over multiple catalytic steps that is remarkable for a comparatively unoptimized enzyme developed de novo from a random sequence pool. The convergent evolution of specificity mechanisms in phylogenetically unrelated proteinaceous polymerases and polymerase ribozymes suggests that chemical as well as informational fidelity are emergent properties of polymerase enzymes. © 2013 Royal Society of Chemistry.status: publishe

Ice as a medium for RNA-catalysed RNA synthesis and evolution

A critical event in the origin of life is thought to have been the emergence of a molecule capable of self-replication and evolution. According to the RNA World hypothesis, this could have been an RNA polymerase ribozyme capable of generating copies of itself from simple nucleotide precursors. In vitro evolution experiments have provided modern examples of such ribozymes, such as the R18 RNA polymerase ribozyme, exhibiting basic levels of this crucial catalytic activity; R18’s activity, however, falls far short of that required of an RNA replicase, leaving unanswered the question of whether RNA can catalyse its self-replication. This thesis describes the development and use of a novel in vitro selection system, Compartmentalised Bead-Tagging (CBT), to isolate variants of the R18 ribozyme with improved sequence generality and extension capabilities. CBT evolution and engineering of polymerase ribozymes, together with RNA template evolution, allowed the synthesis of RNA molecules over 100 nucleotides long, as well as the RNA-catalysed transcription of a catalytic hammerhead ribozyme. This demonstrates the catalytic capabilities of ribozyme polymerases. The R18 ribozyme was also exploited as an analogue of a primordial replicase, to determine replicase behaviour in different reaction environments. Substantial ribozyme polymerisation occurred at −7˚C in the liquid eutectic phase of water-ice; increased ribozyme stability at these low temperatures allowed longer extension products to be generated than at ambient temperatures. The concentration effect of eutectic phase formation could also yield RNA synthesis from dilute solutions of substrates, and provide quasicellular compartmentalisation of ribozymes. These beneficial physicochemical features of ice make it a potential protocellular medium for the emergence of primordial replicases. Ice also could serve as a medium for CBT, allowing the isolation of a polymerase ribozyme adapted to the low temperatures in the ice phase, demonstrating the primordial potential and modern feasibility of ribozyme evolution in ice.The MRC Laboratory of Molecular Biology and St. John’s College, Cambridge provided financial support

Direct and host-mediated interactions between Fusarium pathogens and herbivorous arthropods in cereals

Fusarium head blight and fusarium ear rot diseases of cereal crops are significant global problems, causing yield and grain quality losses and accumulation of harmful mycotoxins. Safety limits have been set by the European Commission for several Fusarium-produced mycotoxins; mitigating the risk of breaching these limits is of great importance to crop producers as part of an integrated approach to disease management. This review examines current knowledge regarding the role of arthropods in disease epidemiology. In the field, diseased host plants are likely to interact with arthropods that may substantially impact the disease by influencing spread or condition of the shared host. For example, disease progress by Fusarium graminearum can be doubled if wheat plants are aphid-infested. Arthropods have been implicated in disease epidemiology in several cases and the evidence ranges from observed correlations between arthropod infestation and increased disease severity and mycotoxin accumulation, to experimental evidence for arthropod infestation causing heightened pathogen prevalence in hosts. Fusarium pathogens differ in spore production and impact on host volatile chemistry, which influences their suitability for arthropod dispersal. Herbivores may allow secondary fungal infection after wounding a plant or they may alter host susceptibility by inducing changes in plant defence pathways. Post-harvest, during storage, arthropods may also interact with Fusarium pathogens, with instances of fungivory and altered behaviour by arthropods towards volatile chemicals from infected grain. Host-mediated indirect pathogen–arthropod interactions are discussed alongside a comprehensive review of evidence for direct interactions where arthropods act as vectors for inoculum

Selection platforms for directed evolution in synthetic biology

Life on Earth is incredibly diverse. Yet, underneath that diversity, there are a number of constants and highly conserved processes: all life is based on DNA and RNA; the genetic code is universal; biology is limited to a small subset of potential chemistries. A vast amount of knowledge has been accrued through describing and characterizing enzymes, biological processes and organisms. Nevertheless, much remains to be understood about the natural world. One of the goals in Synthetic Biology is to recapitulate biological complexity from simple systems made from biological molecules – gaining a deeper understanding of life in the process. Directed evolution is a powerful tool in Synthetic Biology, able to bypass gaps in knowledge and capable of engineering even the most highly conserved biological processes. It encompasses a range of methodologies to create variation in a population and to select individual variants with the desired function – be it a ligand, enzyme, pathway or even whole organisms. Here, we present some of the basic frameworks that underpin all evolution platforms and review some of the recent contributions from directed evolution to synthetic biology, in particular methods that have been used to engineer the Central Dogma and the genetic code

Trinucleotide substrates under pH–freeze–thaw cycles enable open-ended exponential RNA replication by a polymerase ribozyme

RNA replication is considered a key process in the origins of life. However, both enzymatic and non-enzymatic RNA replication cycles are impeded by the ‘strand separation problem’, a form of product inhibition arising from the extraordinary stability of RNA duplexes and their rapid reannealing kinetics. Here we show that RNA trinucleotide triphosphates can overcome this problem by binding to and kinetically trapping dissociated RNA strands in a single-stranded form, while simultaneously serving as substrates for replication by an RNA polymerase ribozyme. When combined with coupled pH and freeze–thaw cycles, this enabled exponential replication of both (+) and (−) strands of double-stranded RNAs, including a fragment of the ribozyme itself. Subjecting random RNA sequence pools to open-ended replication yielded either defined replicating RNA sequences or the gradual emergence of diverse sequence pools. The latter derived from partial ribozyme self-replication alongside generation of new RNA sequences, and their composition drifted towards hypothesized primordial codons. These results unlock broader opportunities to model primordial RNA replication