smomalley's blog

Alzheimer's disease is a neurodegenerative disease that typically affects adults over 65 years old. The disease is caused by abnormally high levels of beta amyloid protein and tau protein. The beta amyloid protein clusters in high numbers between neurons and eventually impede the signaling of the neurons, leading to death of the neurons. The tau proteins structure the microtubules in the axons. In alzheimer's the tau proteins deform and they impede the trasnport of molecules form the soma to the axon terminal. This also eventually impedes the signaling of the neurons and causes neuron death. Late onset alzheimer's disease has a genetic pre disposition involed in it, unlike early onset alzheimer's where there is a genetic mutation that can be passed from generation to generation. In late onset alzheimer's disease, the e4 allele of the APOE gene causes the pre disposition to the disease. The APOE gene is involved in trasnporting cholesterol and lipoproteins. It is believed that this allele in the APOE gene is a predisposition to cardiovascular disease as well as alzheimer's. cholesterol is mainly used by astrocytes which would ideally remove the amyloid plaques, but they don't in alzheimer's patients. 

In genetics labs plasmids are a very valuble tool. Plasmids are circular strands of DNA that are found in bacteria. Plasmids must contain an origin of replication (where DNA polymerase binds), a multiple cloning site (where you can add any gene you want), and a selectable marker (usually an antibiotic resistant gene). These plasmids are used to inserted a selected gene into any cell. If you want a cell to contain a certain gene, you place that gene in the plasmid, then place the plasmid in the cell. The selectable marker is usually an antibiotic resistant gene because this allows you to select for cells that contain the plasmid. You place the cells you believe to have taken up the plasmid on a plate with an antibiotic of your choosing. Only the cells containing the plasmid, with antibiotic gene and the gene of your choosing, will be able to grow on this plate. 

Embryosis is the formation of an embryo. There are two main steps to this process: blastulation, and gastrolation. The sperm and egg cell must fuse to form a zygote. The fusion of sperm and egg allow the genetic material to merge, all cells are pluripotent at this point. Clevage, compaction, and differentiation follow which form the blastocyte. The overall size of the blastocyte is not much bigger than the zygote, due to compaction. There is differentiation between cells in the blastocyte at this point. Gastrolation is the formation of three distinct layers in the blastocyte which will differentiate into different tissues in the bdoy. The top layer is the ectoderm, the middle layer is the mesoderm, and the bottom layer is the endoderm. The ectoderm differentiates into the nervous system and the skin. The mesoderm differentiates into the muscles; the endoderm differentiates into the internal organs. This process is virtually the same for all mamals. The outcome is very different because of the genetic information fused, resulting in a wide range of organisms.

In developmental psych we started talking about morality and when it develops in children. Different psychological experiments have found kids as young as 3 months old have a sense of morality. Multiply psychology labs at colleges all over the country have conducted pupet shows for young children in which one pupet is the "good guy" and one pupet is the "bad guy. The researches show the pupets to the children after the pupet show and over 80% of children chose the "good guy" to play with. With young infants, the amount of time they looked at the "good guy" was more than double the time they spent looking at the "bad guy". This study suggests that we have an innate sense of what is right and what is wrong. A similar pupet show was conducted in which the "bad guy" struggled to open a box, the "good guy" would either slam the box shut, or help the "bad guy" open the box. Children prefered the pupet who slammed the box on the "bad guy", showing that they believed the "bad guy" should be punished for his actions. 

In the brain there are multiple different neural pathways that can affect hunger. But there are rare neurons, that when damaged, cause obesity. One such neuron is the MC4R neuron. This neuron signals for satiety. The POMC neuron excits it and tells the brain that it has enough energy, it doesn't have to eat anything else. The AGRP neuron inhibits the MC4R neuron which then signals for hunger. When the MC4R neuron is silences, the body weight phenotype of the mice tested was doubled. There are numerous experimental methods that can be used to silence the neurons such as rAAV virus to insert diolox sites into the genome of the mouse. This would allow you to insert receptors to specific toxins that not all of the cells have, such as diptherioa toxin or tetnis toxin receptors. By doing this, inserting the toxin into that area of the brain would kill only the cells that succesfully recieved the receptor, causing a loss of function. Loss of function experiments are extrelely useful in determining the function of a specific neuron or neural pathway. 

For this project, we focused on leaf miner damage to different species of Elm trees. We collected 25 leaves from two American Elm, two Japanese Elm, and two Smooth Elm trees. We determined the average number of leaf mines and the percent of aborted leaf mines on each species sampled. We found that the American Elm had the highest average number of leaf mines, with the fewest percent aborted. This could mean that the American Elm is more susceptible to leaf miner damage than the other Elm species sampled.

Embryosis is the formation of an embryo. There are two main steps to this process: blastulation, and gastrolation. To begin, the sperm and egg cell must fuse to form a zygote. The fusion of sperm and egg allow the genetic material to merge, all cells are pluripotent at this point. Next there is clevage, compaction, and differentiation forming the blastocyte. The overall size of the blastocyte is not much bigger than the zygote, due to compaction. There are many more cells in the blastocyte because of clevage, with some differentiation between the inner cell mass and surrounding cells. Gastrolation is the formation of three distinct layers in the blastocyte which will differentiate into different tissues in the bdoy. The top layer is the ectoderm, the middle layer is the mesoderm, and the bottom layer is the endoderm. The ectoderm differentiates into the nervous system and the skin. The mesoderm differentiates into the muscles; the endoderm differentiates into the internal organs. This process is virtually the same for all mamals. The outcome is very different because of the genetic information fused, resulting in a wide range of organisms.

Embryosis is the formation of an embryo. There are two main steps to this process: blastulation, and gastrolation. The begining of this process is the sperm and egg cell fusion to form a zygote. This is when the genetic material merges and all cells are pluripotent. Next there is clevage, compaction, and differentiation forming the blastocyte. The overall size of the blastocyte is not much bigger than the zygote because of compaction. There are many more cells in the blastocyte because of clevage, and some differentiation between the inner cell mass and surrounding cells. Gastrolation is the formation of three distinct layers in the blastocyte which will differentiate. The top layer is the ectoderm, the middle layer is the mesoderm, and the bottom layer is the endoderm. The ectoderm differentiates into the nervous system and the skin. The mesoderm differentiates into the muscles; the endoderm differentiates into the internal organs. This process is virtually the same for all mamals. The outcome is very different because of the genetic information fused, resulting in a wide range of organisms.

Dio lox sites are double inverted orientation lox sites. This is a mechanism used by neurobiologists to insert different genes intot the brain of model organisms. The lox sites surround a gene that you want to insert. The gene is in nonsense orientation, meaning it will not be expressed unless it is in the presence of CRE recombinase which is able to flip the gene in certain circumstances. If there are dio lox sites (in the presence of CRE recombinase), then this is a two step process to perminantly flip the transgene into the sense direction to be expressed. The first step is one set of lox sites are brought togehter by the CRE recombinase. One of the lox sites the CRE is acting on will be inserted to the other side of the transgene and the transgene will be flipped. This leaves three lox sites on one side of the transgene, and one lox site on the other side. Of the tree lox sites on one side, two are in a pair and facing the same direction. These lox site pairs, in the presense of CRE will be spliced out of the gene sequence. The splicing of the lox sites from the gene sequence leaves two lox sites from different pairs in each sequence of DNA (one splices, and one with the transgene). Ultimately, this is a perminant change to the DNA because lox sites from different pairs cannot work together, the CRE will not recognize them as a pair. Therefore, the perminant flip will allow for the expression of the transgene in the cells that express CRE recombinase.

Hunger and body weight are negative feedback loops regulated by the brain. The cycles are controlled by leptin and grellin hormones. Leptin POMC neurons signal for satiety by producing alphaMSH. AGRP neurons signals for hunger. The leptin hormone is produced by fat stores and excites the POMC neurons, signals for satiety. Leptin activates AGRP neurons, signaling for hunger. This corresponds with the hunger-sateity curve. When energy is high, fat stores release leptin to signal sateity. When energy is low, the gut releases ghrelin to signal hunger. This allows the brain to regulate when we eat based on energy and food stores.