A Novel Procedure to Identify Genes involved in Electron Transfer of Exoelectrogens
Purpose of research. Microbial fuel cells (MFCs) are bioelectrochemical systems that generate electrical energy by exploiting the extracellular electron transport (EET) capabilities of electrochemically active bacteria (EAB) (Logan 2009). This investigation aims to identify genes involved in driving bacterial EET with a new procedure that enables rapid screening of a side array of genes. These insights may lead to improved MFC performance through enhancing reactor design or genetic engineering EABs (Alfonta 2009). Procedures. MFC metagenomic analysis. Twelve MFCs incubated with four different bacterial samples were operated for approximately one year. The bacterial DNA from before and after incubation was extracted and the 16S rRNA regions were PCR amplified and sequenced. The bacterial community changes were analyzed using the QIIME program to identify bacteria that were being selected. Fosmid Clone Isolation. An E. coli fosmid library (Mewis et al. 2013) that contained genes from EAB inferred in the previous step was incubated in three MFCs. After a 48 hour enrichment period, biofilm samples from the MFCs were extracted and individual clones were isolated and screened in the MFCs individually. An E. coli DH5α strain with no insert DNA was incubated separately as the control. DNA sequencing. Fosmid insert DNA from high-performing clones were extracted, purified using gel electrophoresis, constructed into sequencing libraries and sequenced. Bioinformatics Analysis. The sequences were constructed into larger contigs using the Velvet algorithm package. The open reading frames (ORFs) were inferred and translated into amino acid sequences and annotated with proteins identified from the KEGG, and SEEDs databases using Metapathways 2.5. Results. The changes in bacterial communities from the metagenomic analysis revealed increases in relative abundance in numerous genera from Firmicutes and Bacteroidetes. The MFCs incubated with the fosmid clones generated about 4 times more peak power than the MFCs incubated with the E. coli DH5α. Polarization curves generated for the MFCs demonstrated that the fosmid clones were able to sustain a higher current. Incubation of pure cultures of individual clones yielded four clones with significant performance improvements over the control strain. Protein data from Metapathways outputs reveled both novel and previously reported EET genes encoding for Type IV pilus structures, c-type cytochromes, soluble cytochromes, flavoproteins, and porins. Taxonomy inferences of the gene inserts by the Green Genes database reveal the genes most likely came from the same EABs that were inferred from the metagenomic analysis. Conclusions. The increased performance of the fosmid clone-powered MFCs suggest that the clones carried genes that enhanced their performance in the MFCs. This is further confirmed by polarization curves generated for the MFCs. The results of the taxonomy inferences suggest that the bacteria being selected for in the environmental samples carried genes that enhanced their performance in the MFCs, and that these genes were successfully identified in the subsequent steps. The results of this study demonstrate that using a gain of function approach to rapidly screen a wide array of genes in a gene library may be an efficient method to identify genes that enhance power generation of EABs in MFCs.
HOW HIGH ARE YOU REALLY JUMPING?
Purpose High-jump athletes are not always aware of the exact height they are jumping. They know that they are clearing the height set by the bar, but not their specific height, which may in fact be a record without them even knowing it. The purpose of this project is thus to design and make a device that will enable high-jump athletes to know exactly how high they are jumping. Procedure Background research was conducted and it was confirmed that no similar products are currently available. Possible types of sensors and micro-controllers were then investigated and then both a prototype and model were built to test the concept. Appropriate changes and adjustments were then made to the design until all func-tions were working accordingly. With the assistance of an experienced software de-veloper, a program was designed to communicate the data collected from the sen-sors into a graphical user interface. Results Many variables, contributing to the accuracy of the obtained results, had to be tak-en into consideration. These variables include interference with the sensors, which resulted in less accurate readings, as well as weather conditions. The latter was found not to have as drastic an effect on the results. Conclusion A device that enables athletes to measure the true height they are clearing was suc-cessfully designed and created. This device will thus be able to help motivate athletes by measuring their true capa-bilities.
Filtered Light Frequencies versus Pigment Frequencies
Purpose of the research Experiments were performed to determine if the frequencies of the colours of pigment differ from the frequencies of the colours of filtered light. The third experiment was performed to determine whether the different colours of filtered light have an influence on plant growth. Procedures Experiments I and II were performed in sunlight and the temperatures of different colours of paper, as well as a white paper underneath different colours of transparencies, were measured by means of an infrared thermometer. The Stefan-Boltzmann equation was used for calculations. Experiment III was performed by placing ten spinach seedlings under each of the Code 40 red, green, blue and black/white shade nets. The control, 10 spinach seedlings, had no Code 40 shade net covering. All these spinach seedlings were grown under similar conditions and harvested after 4 weeks. Data In Experiment I the yellow paper was the only colour that did not perform according to the sequence of the white light spectrum (ROYGBIV). The temperature of the different colours of paper determined the amount of energy that was re-emitted. In Experiment II it was determined that the primary colours red, green and blue, as well as yellow of the filtered light, performed according to the white light spectrum. In Experiment III the spinach plants underneath the blue shade net have the highest average fresh mass (g), as well as the largest average leaf area (cm2), while the spinach plants underneath the red shade net have the lowest average fresh mass (g), as well as the smallest average leaf area (cm2). Conclusions In Experiment I the primary colours of the white light spectrum are red, green and blue. When red and green are combined, yellow is obtained. Therefore the temperature of the yellow paper was lower than expected, because only blue light was absorbed, while red, green and yellow light were reflected. In Experiment II all the colours of the transparencies performed according to ROYGBIV. By comparing the amount of energy of the colours of pigment to the colours of the filtered white light spectrum, it became apparent that there is a difference between the frequencies of the colours of pigment and the frequencies of the colours of filtered white light spectrum.