Design, Structure, And Action Of An Artificial Photosynthetic Reaction Center

At the heart of photosystem II is the reaction center, where solar energy is used to separate charge. Set within a large and highly complex protein system, the handful of redox cofactors that make up the reaction center form an electron transport chain that converts the energy of a central, light-activated pigment into a reductant at one end and an oxidant at the other. The central aim of this thesis is to reproduce the charge separating function of photosystem II in a comparatively simple de novo designed protein maquette. The maquette effectively eliminates the complexity contributed by parts of photosystem II that are not directly involved in charge separation and facilitates a streamlined investigation of fundamental factors essential to this function. Previous work has produced light-activatable maquettes that are competent for electron transfer between tetrapyrroles but are unable to trap a charge separated state that is necessary for fuel generation. This thesis details the design, structure, and action of MZH3, a multi-cofactor maquette that stabilizes a long-lived charge separated state. X-ray crystallographic structures of MZH3 are solved in complex with heme B, a synthetic zinc porphyrin, and metal ion cofactors. Despite sharing low sequence identity with natural proteins, MZH3 exhibits significant structural similarity to cytochrome b at the heme site and bacterioferritin at the metal site. Transient absorption spectroscopy shows that the reduced state of heme B is stabilized in the presence of a tyrosine residue for 150 ms after light absorption at pH 9.5. The binding of ferrous iron extends the charge separated state lifetime to 300 ms at pH 7.5. Providing the tyrosine with a hydrogen bond to histidine increases the yield of the charge separated state but decreases its lifetime. Mutation of a heme-ligating histidine to alanine gives rise to an unexpected oxygen binding function with an oxyferrous lifetime of 38 hours, comparable to natural oxygen transport proteins. These results show that MZH3 is a uniquely structured, functional reaction center maquette that is readily adapted to new functions. Continuing development will be directed toward multinuclear metal cluster assembly and in vivo generation of solar fuel from water

Survival Rate of Tribolium Beetles When Exposed to Extreme Diets

Citation: Stewart, N. (2017). Survival Rate of Tribolium Beetles When Exposed to Extreme Diets . 1st Annual Undergraduate Research Experience in Entomology Symposium, November 16, 2016. Manhattam, KS.This research project was set up to determine the suitability of two extreme diets. Since this experiment only used basic extremes, some of the data were already known, or assumed, such as that a flour beetle can survive on a diet of wheat flour (Imura, 1991). In more detailed experiments on this subject, artificial diets can be made for more accurate data, as well as temperature regulation (Romo, 2016). Diet formulation for flour beetles is largely assumed to be just flour. However, the exact components of the diet, such as protein, carbohydrates, fatty acids, and other factors are never really taken into consideration unless testing exact diets specifically. By testing different levels of these factors in diets, we can raise beetles for testing more efficiently (Maner, 2013). I would like to see if any beetles will survive off of a food with no nutritional value, and if there will be enough nutrition for the beetles to start reproduction in any of the jars. This experiment showed that having nutritious food allows for greater survival than a food with no nutritional value. The small amount of good nutrients even allows for the start of reproduction of the beetles, while none was observed in the poor diet. The results from this experiment show the extremes of insect diets, and that it is important to create a good diet formula to ensure the proper growth and development of experimental insect colonies. By continuing testing of different diets, the process of rearing insects can become much more efficient

Them and us: Britain and the European city

Successful European cities combine high growth, good social outcomes and sustainable development. European cities have a range of different specializations, namely, manufacturing, tertiary services, government, to which interact with each other in complex ways. Compared to their United Kingdom counterparts, many big European cities seem to have higher population growth, educational achievement, quality of life and attractiveness to investors. Many cities on the Continent use formal and informal institutions to ensure that planning and investment are consistent across the real geography of cities. Strong executive leadership is visible in most big cities. Cities like Paris, Berlin and Amsterdam are leaders in integrated, affordable and reliable urban transport systems. There are also cities who show ways to combine good public spaces, high-density urban living and a wide range of other uses in inner urban locations. Furthermore, cities like Stuttgart and Helsinki have built up excellent local innovation systems and have touted their offer to research-intensive businesses

Homosexuality and the Pediatrician

Homosexuality is a psychiatric syn drome which begins in childhood. By rec ognizing some of the predisposing factors early, and then using his influence and knowledge to work towards their correc tion, the pediatrician can often play a ma jor role in preventing its development. Homosexuality must be looked upon as the illness which it is. It is not just a "different way of life."Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66638/2/10.1177_000992286600500815.pd

Making the Most of Peri-Urban Ecosystem Services

Ecosystem services are vital for peri-urban and urbanising areas, and the people who live within them. In contexts of rapid urbanisation, these services are under threat from redevelopment, pollution and overconsumption, and there are gaps in the policies and structures that should protect them. Despite these challenges, there are opportunities for local authorities and citizens to work together and join up policy with action on the ground. Peri-urban ecosystems can provide vital support for functions such as disaster risk management, flood control, reduction of urban heat island effects, air and water purification, food and water security, and waste management. Supporting them is essential in order to meet national government policies and commitments on multiple issues linked to environment, health and poverty reduction, the Sustainable Development Goals and the resilient cities agenda. There are important governance challenges involved in safeguarding and harnessing peri-urban ecosystem services. These include rapid change, ambiguity over boundaries, and gaps in policies and regulations. Involving communities in appraisal and decision-making is crucial to the success of initiatives to protect peri-urban ecosystem services. Taking account of local cultures and histories is important. In many cases, the process will also provide crucial missing data and insights, build trust and avoid misunderstandings. There is a need to share good practice, cases and opportunities between municipalities; and to provide opportunities for decision-makers at national level to learn from them. This briefing was prepared for the Ecosystem Services and Poverty Alleviation (ESPA) programme and draws on material from the Risks and Responses to Urban Futures project

Gradel

Grading homework is a major time-consuming process for professors. This is especially true of computer science professors who each teach multiple sections and classes. Our Senior design project, Gradel is a web application created to help professors with this task. It does this in two ways, firstly by allowing the professors to create customized assignments, problems, test cases and correct solutions. After a class is created our application compares the student\u27s submission with the professor’s solution to automatically grade the submissions. This is also very helpful for students, by giving them instant feedback it allows them to make corrections or get feedback immediately instead of days later. Secondly it records and stores students submissions allowing a professor to easily see how their class is doing with a table of each individual’s grades on the different assignments. A second key feature of Gradel is the coding contest aspect. This allows professors to hold contests on campus such as the annual programming contest. The contests also have automatic grading as well as additional features for contest judges and a live scoreboard for all participants. Thus Gradel simplifies the process of homework creation, submission, modification, and grading making life easier for professors and students alike

Diffusion as a Ruler: Modeling Kinesin Diffusion as a Length Sensor for Intraflagellar Transport

An important question in cell biology is whether cells are able to measure size, either whole cell size or organelle size. Perhaps cells have an internal chemical representation of size that can be used to precisely regulate growth, or perhaps size is just an accident that emerges due to constraint of nutrients. The eukaryotic flagellum is an ideal model for studying size sensing and control because its linear geometry makes it essentially one-dimensional, greatly simplifying mathematical modeling. The assembly of flagella is regulated by intraflagellar transport (IFT), in which kinesin motors carry cargo adaptors for flagellar proteins along the flagellum and then deposit them at the tip, lengthening the flagellum. The rate at which IFT motors are recruited to begin transport into the flagellum is anticorrelated with the flagellar length, implying some kind of communication between the base and the tip and possibly indicating that cells contain some mechanism for measuring flagellar length. Although it is possible to imagine many complex scenarios in which additional signaling molecules sense length and carry feedback signals to the cell body to control IFT, might the already-known components of the IFT system be sufficient to allow length dependence of IFT? Here we investigate a model in which the anterograde kinesin motors unbind after cargo delivery, diffuse back to the base, and are subsequently reused to power entry of new IFT trains into the flagellum. By mathematically modeling and simulating such a system, we are able to show that the diffusion time of the motors can in principle be sufficient to serve as a proxy for length measurement. We found that the diffusion model can not only achieve a stable steady-state length without the addition of any other signaling molecules or pathways, but also is able to produce the anticorrelation between length and IFT recruitment rate that has been observed in quantitative imaging studies