Development of phage-assisted evolution and riboregulation strategies

Riboswitches are short RNA sequences that undergo a structural modification in the presence of a specific molecule, regulating gene expression in the process. A few examples of riboswitches have been described in eukaryotes, but they are present in many species of bacteria. These molecules are of great interest in synthetic biology for their inductive regulatory properties, which could be used in metabolic studies, or as biosensors in medical, industrial or environmental contexts. However, riboswitches are very substrate-specific, creating a problem for their use with novel compounds; and current development procedures suffer from issues such as being too laborious and not using in vivo conditions. By developing strategies based on Phage Assisted Continuous Evolution (PACE) and using T7 phage along with a double selection system, we aim to develop a way of obtaining riboswitches that show improvements compared to a control sequence or with a different specificity. This procedure could even be used to develop novel riboswitches not present in nature. Once the method is properly established, the strategy could be used not only for the directed evolution of riboswitches, but also other types of sensors, such as protein or RNA receptors. Alternative evolution strategies based on phage transduction were also tested, along with inducible RNA systems based on the phage Qb. These three processes have yielded different results, namely a randomised library of theophylline riboswitch sequences in phages, a working transduction system, and an inducible RNA plasmid, respectively. In the first case, by using a double selection process to achieve evolution, we have shown sequence variation within the phage populations progressively decreased over time, until a single sequence was prominently represented in the population. The sequence showed higher activation folds at a lower concentration of the activating molecule than in initial generations, taken as an indication that evolution had taken place. This library was also adapted into the transduction strategy thanks to the use of a working T7 phage packaging signal. As for the RNA-based plasmid system, we have shown it to be an inducible, transient expression system that could be used as a novel way to regulate gene expression and bypass CRISPR systems. This set of results speak of the possibilities held by these strategies, not just for their specific areas of research, but for synthetic biology at large, from bioremediation to treatment

Rollins Catalogue, 1981-1982

Rollins College catalogue 1981-1982 with list of faculty and students and courses by department

The Siren of Cirebon: a tenth-century trading vessel lost in the Java Sea

This thesis examines data collected during the salvage of the cargo of a merchant ves-sel foundered in the Java Sea, by a short inscription in a fragment of a bowl and coins dat-ed to around 970 CE. The wreck’s position indicates that the ship was on her way to the island of Java; the verssel herself belongs into the so called ‘lashed-lug and doweled’, Western Austronesian (‘Malayo-Indonesian’) tradition of boat-building. The surviving cargo ranges from Chinese stonewares and Southeast Asian ceramics to Middle Eastern glassware, tin and lead from –proposedly– the Malay Archipelago, and a wide variety of “smaller finds”, most of which can be attributed to the broader area of the western Indian Ocean. The find palpably demonstrates the far-reaching and well-institutionalised trade rela-tions throughout early medieval Asia. It is often assumed that pre-modern Asian com-merce was largely organised in small-scale ventures, the so called “pedlar trade”, and a number of sources indicate structural features of the ships facilitating this commerce that could have supported such a “particularised” exchange. However, a critical assessment of the composition and distribution of the ship’s payload and a virtual reconstruction of the ship and her initial loading pattern reveal that the vessel’s ceramic cargo in all probability was not acquired, handled, and bound to be marketed as a particularised “peddling” ven-ture, but managed by a single authority. The huge amount of ceramics carried on the ves-sel raises questions regarding frequency, volume and modus operandi of maritime ex-changes in tenth-century Southeast Asia, implying that the ship’s tragic voyage was but an attempt at instituting a virtual monopoly in such trade

Report of the Secretary of the Interior; being part of the message and documents communicated to the two Houses of Congress at the beginning of the second session of the Fifty-second Congress : Annual Report of the Commissioner of Education, 1892

Annual Message to Congress with Documents; Pres. Harrison. 6 Dec. HED 1, 52-2, v1-22 , 16378p. [3076-3097] Cession of the Cherokee Strip and other Indian lands to the U.S.; policy of allotment and education ; Choctaw and Chickasaw title to lands occupied by other tribes; annual report of the Sec. of War (Serials 3077-3084); annual report of the Sec. of Interior (Serials 3087-3094); annual report of the Gen. Land Office (Serial 3087) ; annual report of the CIA (Serial 3088); etc

Topical Workshop on Electronics for Particle Physics

The purpose of the workshop was to present results and original concepts for electronics research and development relevant to particle physics experiments as well as accelerator and beam instrumentation at future facilities; to review the status of electronics for the LHC experiments; to identify and encourage common efforts for the development of electronics; and to promote information exchange and collaboration in the relevant engineering and physics communities