Dr. Brown Immune Experiment Summary
Dr. Brown conducted three distinctive experiments in order to understand how an individual’s immunological phenotype is the result of its genotype, the environment, and development. For the first experiment, Dr. Brown’s research was testing how selection on basal and maximal metabolic rates affect immune function. In addition, Dr. Brown had four hypotheses for this particular experiment, two were for basal metabolic rate and two were for maximal metabolic rate. Moreover, trade-off with BMR decreases as basal metabolic rate increases, and assimilation increases as basal metabolic rate increases. Furthermore, trade-off with MMR decreases as maximal metabolic rate decreases as well as energetic capacity increases as maximal metabolic rate increases.
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As far as the design of the experiment goes, Dr. Brown used mice from an artificial selection experiment. Example: mice selected for metabolism.
The selection treatment consisted of mass-independent metabolic rates, basal and maximal. The sample size for the mice is n=12 which means that there are 4 replicates. BMR measurements were made using mouse treadmills. Each mouse had an hour to run on the treadmill, and the speed was increased incrementally. Selection treatments worked as the mice that have the lowest MMR (control) do not have the lowest BMR (antagonistic). Dr. Brown did innate immune experiment to measure BMR and MMR, where the mice were inoculated with sham or LPS, LPS essentially initiates immune response. In addition, quantified plasma TNF- was measured because LPS > macrophage response. BMR wasn’t related to inflammation as TNF-: LR= 12.31, p<0.01. Selection for high-MMR suppressed innate immunity and Dr. Brown wanted to determine what is the potential mechanism? The determination was changes in signaling networks, specifically, glucocorticoids, as well as selection for an exercise phenotype. Overall, Dr. Brown believes that MMR may be an important architect for immune function and correlates of MMR should be studied when considering the evolution of metabolic …show more content…
rates.
Another research question Dr.
Brown conducted an experiment on was how population density affects investment in immune function. Female elk were largely used in the experiment; elk were used for the experiment as they exhibit slow-paced life histories consisting of long life spans and large body size. Elk trade-off current reproduction for future reproduction, which means they will forego reproduction for the next time if not able to survive and it is facilitated by the body condition in the elk. Additionally, one male elk will reproduce with many female elk. The hypothesis is that there will be a positive relationship between immune function and max fat up to a threshold. Complement Cascade consisted of an invading cell where it was tagged by antibodies and complement activated. Dr. Brown measured the complement pathway through the bacteria killing ability using a serum that was mixed with the bacteria which in turn allowed to measure the percentage of bacteria killed. Hemolytic-complement activity was also measured through serum mixing with SRBC and anti-SRBC antibodies which allowed for the percentage of cells lysed to be able to be recorded. Dr. Brown aimed to see if population density had an effect on the parasite load, and she concluded it does. Additionally, she came to the conclusion that not just density has an effect, but age as well. Furthermore, Dr. Brown concluded the duration of individuals that infectious has a direct correlation to the frequency of the spread
of parasites.
The third and final research question that Dr. Brown wanted to explore the parallel between the immune defense and environment, age, sex, condition in golden eagles. Dr. Brown hypothesized that the fortification of the immune system increases with age, sex: females higher than males, and the individual condition. As far as the sample size goes, Dr. Brown and her group of researchers conducted the study in three separate states which consisted of Idaho, Oregon, and California which each having a particular number of nests (ID: 17 nests, OR: 31 nests, CA: 11 nests). Also, all of these were sampled twice measuring blood smears for hemolytic-complement activity and bacteria. The sample sizes for these were Hemolytic-complements activity (N = 98 Total observ. = 135) and Bacteria Killing (N= 91 Total observ. = 137). Dr. Brown utilized the same methods as to measuring the complement pathway to obtain results. Dr. Brown drew a few conclusions for this experiment, one being that complement, but not natural antibodies, were affected by sex. Also, that the H:L ratio had a favorable connection with immunity which was the opposite of she initially anticipated. In addition, that the birds with highest (of the 3 states tested) immune defenses came from Oregon. Future directions that can be taken from this study is nitrogen deficiency and its connection to pregnancy. Another question that could have been answered in the study or future ones, “Was there any benefit to low level of infection” (Dr. Wise)?
Dr. Brown addressed the significance of the studies she conducted at the beginning and at the end of her presentation, and background information was provided as well. Dr. Brown did present her hypotheses but she might have had a bit too many, on top of the three separate research questions, it got a little difficult to keep up with her. The experimental designs and techniques were fitting for the hypotheses as they allowed her and her team to come up with results. Also, the conclusions match the results, as Dr. Brown came up with a new conclusion through her results. This would have to do with her third study involving the H:L ratio and it’s favorable connection with immunity which was the opposite of she initially anticipated. By Dr. Brown sharing that information with the audience, it demonstrated that she gave us an unbiased assessment of what she was presenting. Dr. Brown did a good job presenting, but the pace of her presentation was a little too quick for my liking. At points in time, she would go through slides quite quickly in order to cover her bigger points for the sake of time. I feel that if she did not have such a number of hypotheses and even research questions, it could have gone a bit smoother. All of the information on the slides including graphs and tables were clear and easy to understand, and Dr. Brown did a good job explaining them without using jargon that would have been to understand. Dr. Brown engaged the audience well too, as I felt like she was comfortable and flexible throughout the duration of her presentation. I recall her mentioning that since she is a professor and has the experience, that we were able to ask questions in the middle of the presentation which I feel was good to hear. Overall, the presentation went quite well and the only problems I had with it were the amount of hypotheses and research questions.
As far as the design of the experiment goes, Dr. Brown used mice from an artificial selection experiment. Example: mice selected for metabolism.
The selection treatment consisted of mass-independent metabolic rates, basal and maximal. The sample size for the mice is n=12 which means that there are 4 replicates. BMR measurements were made using mouse treadmills. Each mouse had an hour to run on the treadmill, and the speed was increased incrementally. Selection treatments worked as the mice that have the lowest MMR (control) do not have the lowest BMR (antagonistic). Dr. Brown did innate immune experiment to measure BMR and MMR, where the mice were inoculated with sham or LPS, LPS essentially initiates immune response. In addition, quantified plasma TNF- was measured because LPS > macrophage response. BMR wasn’t related to inflammation as TNF-: LR= 12.31, p<0.01. Selection for high-MMR suppressed innate immunity and Dr. Brown wanted to determine what is the potential mechanism? The determination was changes in signaling networks, specifically, glucocorticoids, as well as selection for an exercise phenotype. Overall, Dr. Brown believes that MMR may be an important architect for immune function and correlates of MMR should be studied when considering the evolution of metabolic …show more content…
rates.
Another research question Dr.
Brown conducted an experiment on was how population density affects investment in immune function. Female elk were largely used in the experiment; elk were used for the experiment as they exhibit slow-paced life histories consisting of long life spans and large body size. Elk trade-off current reproduction for future reproduction, which means they will forego reproduction for the next time if not able to survive and it is facilitated by the body condition in the elk. Additionally, one male elk will reproduce with many female elk. The hypothesis is that there will be a positive relationship between immune function and max fat up to a threshold. Complement Cascade consisted of an invading cell where it was tagged by antibodies and complement activated. Dr. Brown measured the complement pathway through the bacteria killing ability using a serum that was mixed with the bacteria which in turn allowed to measure the percentage of bacteria killed. Hemolytic-complement activity was also measured through serum mixing with SRBC and anti-SRBC antibodies which allowed for the percentage of cells lysed to be able to be recorded. Dr. Brown aimed to see if population density had an effect on the parasite load, and she concluded it does. Additionally, she came to the conclusion that not just density has an effect, but age as well. Furthermore, Dr. Brown concluded the duration of individuals that infectious has a direct correlation to the frequency of the spread
of parasites.
The third and final research question that Dr. Brown wanted to explore the parallel between the immune defense and environment, age, sex, condition in golden eagles. Dr. Brown hypothesized that the fortification of the immune system increases with age, sex: females higher than males, and the individual condition. As far as the sample size goes, Dr. Brown and her group of researchers conducted the study in three separate states which consisted of Idaho, Oregon, and California which each having a particular number of nests (ID: 17 nests, OR: 31 nests, CA: 11 nests). Also, all of these were sampled twice measuring blood smears for hemolytic-complement activity and bacteria. The sample sizes for these were Hemolytic-complements activity (N = 98 Total observ. = 135) and Bacteria Killing (N= 91 Total observ. = 137). Dr. Brown utilized the same methods as to measuring the complement pathway to obtain results. Dr. Brown drew a few conclusions for this experiment, one being that complement, but not natural antibodies, were affected by sex. Also, that the H:L ratio had a favorable connection with immunity which was the opposite of she initially anticipated. In addition, that the birds with highest (of the 3 states tested) immune defenses came from Oregon. Future directions that can be taken from this study is nitrogen deficiency and its connection to pregnancy. Another question that could have been answered in the study or future ones, “Was there any benefit to low level of infection” (Dr. Wise)?
Dr. Brown addressed the significance of the studies she conducted at the beginning and at the end of her presentation, and background information was provided as well. Dr. Brown did present her hypotheses but she might have had a bit too many, on top of the three separate research questions, it got a little difficult to keep up with her. The experimental designs and techniques were fitting for the hypotheses as they allowed her and her team to come up with results. Also, the conclusions match the results, as Dr. Brown came up with a new conclusion through her results. This would have to do with her third study involving the H:L ratio and it’s favorable connection with immunity which was the opposite of she initially anticipated. By Dr. Brown sharing that information with the audience, it demonstrated that she gave us an unbiased assessment of what she was presenting. Dr. Brown did a good job presenting, but the pace of her presentation was a little too quick for my liking. At points in time, she would go through slides quite quickly in order to cover her bigger points for the sake of time. I feel that if she did not have such a number of hypotheses and even research questions, it could have gone a bit smoother. All of the information on the slides including graphs and tables were clear and easy to understand, and Dr. Brown did a good job explaining them without using jargon that would have been to understand. Dr. Brown engaged the audience well too, as I felt like she was comfortable and flexible throughout the duration of her presentation. I recall her mentioning that since she is a professor and has the experience, that we were able to ask questions in the middle of the presentation which I feel was good to hear. Overall, the presentation went quite well and the only problems I had with it were the amount of hypotheses and research questions.