Blogs

Figures 2-5 depict the amount of organisms in each vial by percent, separated by developmental stage. It is apparent that the control group yielded the highest percentage of pupae, at about 55%. Groups treated with precocene experienced a much lower percent yield of pupae, with 0.1 μM precocene yielding the lowest at 13.7%. The control yielded the lowest percentage of adults, at 30.6%, while 1 μM precocene yielded the highest percentage of adults at 55%. Most of the larval d. melanogaster were found in the 0.1 μM precocene group, with 45% of that group containing larvae. The control contained the least amount of larvae percentage, with only 14.3% making up that group.

The data below demonstrates the difference between growth and maturation of flies treated with different levels of precocene, and flies not treated with precocene. Table 1 displays the raw counts collected from the vials, where each organism was counted and grouped by developmental stage. Table 2 shows the measured fly lengths of 5 males and 5 females from each treatment group. Figure 1 displays the average fly lengths for males and females for each treatment group graphically. It is apparent that both males and females had the same average length within each treatment group, except for 1 μM precocene. Additionally, it is shown that 0.1 μM precocene treated flies have the longest average length, with an average length of 0.45 millimeters for both male and female. Male flies treated with 1 μM Precocene appear to have the shortest average fly length, with an average length of 0.32 millimeters.

Over thirty years ago the idea of stem-cell research was introduced to the scientific world, now thirty years later the research and the technology for stem cells has advanced tremendously. Stem cells have the amazing potential ability to develop into many different stem cells in the body, and due to its regenerative abilities stem cell research offers promises of disease treatment for diseases such as diabetes, spinal cord injury, Parkinson’s disease, and heart disease.

What were the authors trying to test, and what predictions did they make?

Elk were introduced to Afognak Island, Alaska in 1929. Only 8 elk were introduced, but the population peaked at 1,400 in 2009. The authors studied specific loci in this unique population to examine founder effect and bottleneck effect. The purpose of the experiment was to determine the effects of translocation and demography on genetic variation. The isolated population was expected to vary significantly from their parent population due to the population experiencing a genetic bottleneck and founder effect. Therefore the population would suffer a significant loss in allelic diversity.

What, exactly, did the authors do?

The authors studied microsatellite loci in the Afognak population and compared them to the parent population. Microsatellites were used because they have a high degree of polymorphism. Tissue samples of elk from Afognak island and Olympic Peninsula were conducted. The Olympic Peninsula is where the elk that were introduced to Afognak island originated from. DNA extraction, amplification and genotyping took place, fifteen specific microsatellites were chosen to represent the elk genome.

What did the authors find (i.e, what were their data)?

The authors found that the two populations of Elk differed in both allele and genotype frequencies. Specifically 10 of 15 allele frequencies differed, and 11 of 15 genotype frequencies differed.  One specific loci exhibited excess heterozygosity in Afognak. Another loci exhibited a deficit in heterozygosity in the Olympic population. The inbreeding coefficient for the Afognak population was 0.019, and -0.006 for the founder population. Surprisingly, a genetic bottleneck in the Afognak population was not found.“Despite the demographic bottleneck, no evidence of a genetic bottleneck in the Afognak population was detected using a test for heterozygosity excess or mode shift of allele frequencies.”

How did the authors interpret their findings?

    The authors concluded that the combined founder and bottleneck effect resulted in a significant reduction in allelic diversity and heterozygosity. They were unable to reject the null hypothesis of no bottleneck and no inbreeding. One possible source of error is that the Olympic population, which yielded the Afognak founders, was not genetically identical 70 years later. This study demonstrated bottleneck detection, which  can be a helpful tool for endangered species management.

I skimmed a scientific paper from genetic.org called "Dissection of Floral Pollination Syndromes in Petunia". It discusses animal.mediated pollination and how it is important for the reproductive ways of many plants that have flowers. Many of these pollination systems display complex traits and are convergent, meaning the evolved separately but display many of the same structural features. This paper focuses on the genus Petunia and describes the complez syndromes for P. axillaris, the nocturnal hawkmoth, and P. integrifolia, dirunal bees. Differences in petal color, corolla shape, reproductive organ morphology, amount of nectar, and scent were studied. 

The purpose of DNA extraction is to obtain DNA in a relatively purified form. This can then be used to analyze using PCR or sequencing the DNA obtained. In a DNA extraction procedure there are essential components which are to maximize DNA recovery, remove inhibitors, remove or inhibit nucleases, maximize the quality of DNA, and double strand vs. single strand (RFLP or PCR). There are a variety of most commonly used DNA extraction procedures. The method utilized may be sample dependent, technique dependent, cost depedndent, or analyst preference. 

Identity and purity were assessed. Analyzation methods of the products obtained included Gas Chromatography and IR spectroscopy. When obtaining the IR analysis, it illustrated the bonds contained in the product obtained. There is a singlet peak present in the IR analysis at around 1450 cm^-1. This indicates the double bond between two carbons. The significant peak signified at the 3000 cm^-1 may indicate an impurity which may be due to the presence of water. In addition, there is a quadruplet present at around 1600 cm ^-1. The gas chromatography illustrated that 100% of the area fell under one peak indicating that the product was made up of only cyclohexene and had a retention rate of 0.058. It also indicates in the gas chromatography that the total area is 9596.

During this experiment, cyclohexanol reacted with phosphoric acid under high temperature to perform the acid catalyst dehydration reaction and produced the target product of cyclohexene which was obtained in a 18.87% yield. The percent yield of 18.87% indicates 81.13% of the original amount was lost. A gas chromatography and infrared analysis readings were taken which illustrated data regarding retentions and peaks. In addition, two chemical tests were performed in a 3% solution of bromine in dichloromethane and 1% potassium permanganate and 10% sulfuric acid. These were known as the bromine in dichloromethane and potassium permanganate chemical tests. When performing the bromine in dichloromethane test for alkenes, the cyclohexene solution started out as clear and colorless and remained clear after the addition of bromine while cyclohexane started out as clear and colorless and turned to a color known as reddish-orange instantly when swirled. For the 1% potassium permanganate and 10% sulfuric acid test for alkenes, cyclohexane started out as a clear color and then turned into a brown precipitate. The cyclohexane started out as clear and converted into purple after the addition of KMnO₄. 

The job seminar was very interesting, it was about how they could change the spindles and what possible applications they could have. One drawback to the seminar was that there were some technical difficulties so Professor Gatlin was unable to talk for the entire time. He began the seminar by giving an overview of cells and microtubules. One of the most interesting points that he brought up was that cell structures scale along with the size of the cell, similar to how organs scale inside different species of animals. His lab had an experiment where they controlled the size of the droplets of cell extract, and they found that the spindle size correlated with the width of the droplet. He then described the future uses of his research. He proposed that he can develop layered hydrogels in order to measure the forces that are exerted by the microtubules.

    I would recommend that the biology department hires Professor Gatlin. I find it very interesting that he is from a mechanical engineering background. It gives him a different perspective on how the mechanical processes of the cell transpire. He made the seminar entertaining, because he was a pretty funny guy. His power point contained many videos and animations that really helped him get his point across. I would love to have a class with him as a teacher.

Turn on the sand bath right away after entering the lab keeping the temperature under 40 degrees. Phosphoric acid will be used however the measurement does not need to be exact. Amount of cyclohexanol used however must be exact, this can be done by taking rb flash 30 mL beaker upright then balance set it to zero. Measure about 2.0 grams of cyclohexanol using a pipet. Then use a buret in the hood to add 85% phosphoric acid (0.5 mL). Set up fractional distillation, can be done by using black plastic connector. Heat it up at a slow constant rate rather than a fast rate, the drops should be about 20-30 seconds per drop. Do it until only 10% is left. In the vial, there should be 2 phases of liquid which are water and cyclohexene. Pipet the contents of the vial into a test tube adding water (~1 mL). Mix the two liquids and then remove the lower aqueous layer and place it in a waste beaker. Add 1M sodium hydroxide (1 mL) then mix well to remove bottom layer again. Then add brine (1-2 mL) to mix and remove lower aqueous layer once again and place in the waste beaker after. Using a dry pipet, transfer organic layer, it is organic because there should not be any more water in the liquid. Add several spheres of calcium chloride and mix it well but not crushing the spheres. Repeat it until the spheres are no longer clumping together. Transfer the dried product then sign up for GC / IR analysis. Calculate the percent yield showing hand-written calculations on a separate piece of lab notebook paper. Chemical test will need to be done to distinguish alkenes from alkanes. Run the test reactions on the product that was formed and the cyclohexane. Dichloromethane is toxic so when using avoid touching. Rinse if it touched. Bromine is reddish-orange and it reacts with alkene to form a colorless dibromide. The solution will decolorize until all of the alkene has been reacted. Take cyclohexene (0.5 mL) and cyclohexane (0.5 mL) adding together, then take 3% solution of bromine in dichloromethane and add 3 to 4 drops. For potassium permanganate which is purplish color, add cyclohexene (0.3 mL) and cyclohexane (0.3 mL) together then drop about 2 or 3 drops of an aqueous solution containing 1 percent potassium permanganate and 10% sulfuric acid. Things to look out for in this lab is cyclohexene as it is very flammable. Handle phosphoric acid with care it is very corrosive to tissue. If the skin touches phosphoric acid even a little, immediately wash the contaminated area with water using soap. Clean up spills using sodium bicarbonate in the hood and rinse all the apparatus in the waste hood with a small amount of acetone. Dispose it in the organic liquid waste container after. Make sure to save copper wire, sponge, and aluminum foil for future use.