Optical switching between long-lived states of opsin transmembrane voltage sensors

Opsin-based transmembrane voltage sensors (OTVSs) are membrane proteins increasingly used in optogenetic applications to measure voltage changes across cellular membranes. In order to better understand the photophysical properties of OTVSs, we used a combination of UV-Vis absorption, fluorescence and FT-Raman spectroscopy to characterize QuasAr2 and NovArch, two closely related mutants derived from the proton pump archaerhodopsin-3 (AR3). We find both QuasAr2 and NovArch can be optically cycled repeatedly between O-like and M-like states using 5-min exposure to red (660 nm) and near-UV (405 nm) light. Longer red-light exposure resulted in the formation of a long-lived photoproduct similar to pink membrane, previously found to be a photoproduct of the BR O intermediate with a 9-cis retinylidene chromophore configuration. However, unlike QuasAr2 whose O-like state is stable in the dark, NovArch exhibits an O-like state which slowly partially decays in the dark to a stable M-like form with a deprotonated Schiff base and a 13-cis,15-anti retinylidene chromophore configuration. These results reveal a previously unknown complexity in the photochemistry of OTVSs including the ability to optically switch between different long-lived states. The possible molecular basis of these newly discovered properties along with potential optogenetic and biotechnological applications are discussed.Solid state NMR/Biophysical Organic Chemistr

Phenotypic characterization of naturalized swine breeds in Brazil, Uruguay and Colombia

Foram colhidos dados morfométricos de 859 suínos naturalizados do Brasil (Piau, Tatu, Nilo, Caruncho, Casco de Burro, Moura, Monteiro e Rabo de Peixe), Colômbia (Criolla Zungo, Sanpedreño e Casco de Mula) e Uruguai (Mamellado) Dados sobre raça, sexo e idade foram coletados, assim como varias avaliações morfométricas. A análise de variância foi realizada utilizando-se o procedimento PROC GLM do SAS sobre os dados morfométricos. Os coeficientes de variância oscilaram de 11,50 a 83,81% e o coeficiente de determinação foi de moderado a alto. As fêmeas foram em geral menores na maioria das avaliações em relação aos machos, indicando dimorfismo sexual. A Moura foi a raça naturalizada mais próxima das raças comerciais, seguida da Piau, enquanto a Monteiro apresentou-se mais distante. O dendograma obtido a partir de informações morfológicas apresentou divisão dentro de três grupos. A caracterização foi possível utilizando-se dados morfológicos e morfométricos.ABSTRACT: Morphometric data was collected on 859 naturalized swine in Brazil (Piau, Tatu, Nilo, Caruncho, Casco de Burro, Moura, Monteiro and Rabo de Peixe), Colombia (Criolla Zungo, Sanpedreño and Casco de Mula) and Uruguay (Mamellado), both on farm and in published material. Information was collected on breed, sex and age, as well as various morphometric measurements. Analysis of variance was carried out using PROC MIXED of SAS ® on phenotypic data. The coefficients of variance varied between 11.50 and 83.81%, and the coefficient of determination was medium to high. Females were in general smaller for most measurements than males, showing sexual dimorphism. The Moura was the closest naturalized breed to the commercial breeds, followed by the Piau, while the Monteiro was the furtherest. The dendrogram obtained from morphological information showed a division of the pigs into three groups. Characterization was possible using morphological and morphometric data

Poverty and gender issues

In van Koppen, Barbara; Namara, Regassa; Safilios-Rothschild, Constantina. Reducing poverty through investments in agricultural water management. Colombo, Sri Lanka: IWMIIWMI Working Paper 10

Identifying champion nanostructures for solar water-splitting

Charge transport in nanoparticle-based materials underlies many emerging energy-conversion technologies, yet assessing the impact of nanometre-scale structure on charge transport across micrometre-scale distances remains a challenge. Here we develop an approach for correlating the spatial distribution of crystalline and current-carrying domains in entire nanoparticle aggregates. We apply this approach to nanoparticle-based α-Fe2O3 electrodes that are of interest in solar-to-hydrogen energy conversion. In correlating structure and charge transport with nanometre resolution across micrometre-scale distances, we have identified the existence of champion nanoparticle aggregates that are most responsible for the high photoelectrochemical activity of the present electrodes. Indeed, when electrodes are fabricated with a high proportion of these champion nanostructures, the electrodes achieve the highest photocurrent of any metal oxide photoanode for photoelectrochemical water-splitting under 100 mW cm−2 air mass 1.5 global sunlight