curbano's blog

There are many different checkpoints and regulations to help the cell cycle be carried out correctly and successfully. One very important regulation/mechanism used in the cell cycle is cohesion as well as the breaking down of cohesion. If cohesion does not break down properly or at the right time, it can lead to too many or too few chromosomes in a cell, which can be detrimental. I am interested in knowing what is involved with the formation of the contractile ring in animal cells and the phragmoplast in plant cells. How do these two mechanisms differ? I would assume the phragmoplast would have a method in protecting the cell wall during cytokinesis. If the contractile ring/phragmoplast doesn't function properly, then the single cell can't be divided and there would not be two identical daughter cells as the end product. We have lots of different technology and methods in viewing cells and cell processes. These images remind me of some IF imaging that occurs in the genetics lab I work in. The blue staining is most likely DAPI, which is a DNA marker. Markers can be very helpful in identifying certain structures in the cell, different stages in the cell cycle, and many other pieces of information. It is nice to be able to physically see what is happening in these cells because it gives us a better understanding.

While I have learned about the cell cycle many times in high school as well as college, I never realized how complex this cycle truly is. I was aware of checkpoints and the steps, but there are so many different "switches," mechanisms, and regulations to make sure cells going through replication come out normal. It amazes me that even though the cycle is so complex, for the most part, our cells and we come out fairly normal and function properly. I guess the many regulations prevent errors from occurring, but it still is amazing! I wasn’t sure what nucleating microtubules was or its purpose, so I looked it up. Microtubules nucleation is the process in which tubulin alpha-beta heterodimers begin aggregation to form an oligomeric tubulin structure, also known as a microtubule seed. The microtubule seed then eventually forms into a microtubule. This means that microtubule nucleation is the initiating step in the formation of a microtubule when there are no microtubules present.

In nearly every living species, temperature influences physiological and biological processes in the body. Spiders are ectothermic organisms, meaning they are unable to regulate their body temperatures relative to their environment. Because of this, changes in temperature can have a large impact on their metabolic rate and overall activity (Barghusen et al). It has been found that even winter active spiders will make less effective webs or no webs at all at temperatures 2° colder than the temperature they are accustomed to. Having a less effective, or no, web greatly reduced feeding, which could be detrimental for spiders (Aitchison 1984). Since web production is a large part of spider activity and survival, we decided to focus our project on how varying temperatures influence web production. Past research has found that spiders in lower temperatures tend to use less spiral silk than spiders in warmer temperatures (Vollrath et al). Our project focuses on how temperature influence the weight of webs.

Since scientists still don’t know much about the specific proteins involved with this process, it is hard to give a straight answer. I would assume that the binding site would be the same or at least fairly similar on the different proteins since they all bind to M-Cdk. I never really thought about the fact that protein degradation/proteolysis would be necessary for sister-chromatid separation. However, it makes a lot of sense. If the proteins keeping the chromatids together were still present, it would be much more challenging or even impossible to separate the chromatids. The kinetochore plays a huge role in mitosis, especially sister chromatid separation. While kinetochore sends a signal if the spindle is not properly attached, mutations must occur occasionally. This would most likely lead to an extra chromosome or lack of chromosome in a cell. I wonder if there are any other consequences of a lack of negative signal.

Our experiment will study cellar spider web weight and production in relation to the temperature of their surrounding environment. This experiment can be used as a microcosm for Earth and may show the effects of climate change on cellar spiders.  Globally, species are expected to shift locations in response to climate change. When the area the organisms are in becomes too hot or cold, they move towards the poles or equator accordingly to adjust for the change in temperature. If the area becomes too hot, they will generally move towards the poles in order to stay in an environment that suits their temperature needs. If the area becomes too hot, they will move to a cooler area, such as away from the equator or a higher elevation. Most of the Earth is expected to warm over the next several decades, but there are some areas that are expected to get colder. Physiological processes in the body are often influenced by temperature and the changing temperature can make survival much more challenging.

It makes sense that G1 cells would be able to replicate while G2 cell would not be able to. Even when a signal for replication is present, G2 will not replicate. I would think that the G2 cells must have a signal or something that indicates that it has passed certain checkpoints, such as the DNA replication checkpoint at the end of S phase. The ORC is a multi-subunit SNA binding complex that binds to the orgins of replication in all eukaryotes. It is made up of 6 subunits and ATP is needed for binding to occur. The subunits are encoded by ORC 1, 2, 3, 4, 5, and 6. The ORC is active at the end of mitosis and early G1, which makes sense for replication. While it is highly unlikely since so many different complexes and proteins are involved, what happens if re-replication occurs after S phase? Is this even possible at all? It makes sense that Cdk activity reduces to zero so chromosomes are ready for a new round of replication. It reminds me of a "reset" button.

Our experiment studies cellar spider web weight and production in relation to the temperature of their surrounding environment.  This experiment can be used as a microcosm for Earth and may show the effects that climate change will have on cellar spiders. Globally, species are expected to shift locations in response to climate change.  When the area the organisms are in becomes too hot or cold, they move towards the poles or equator accordingly to adjust for the change in temperature. If the area becomes too hot, they will generally move towards the poles in order to stay in an environment that suits their temperature needs.  If the area becomes too cold, they will move to a warmer area, which is generally towards the equator. Most of the Earth is expected to warm over the next several decades, but there are some areas that are expected to get colder.

We found a paper that dealt with spider web production in terms of web mass and temperatures affect on it. They used 20 female spiders and randomly assigned them to one of their 4 temperature groups. They kept them at the temperature for six days (Barghusen et al). Fruit flies were dropped into the web with an relatively complex apparatus, beyond the scope of our project. They created a gradient of temperatures by putting two aluminum pans on a hot plate. The pans were positioned in such a way that the entire pan wouldn’t get hot. The different temperature regions were indicated by marking on the pan, not barriers that the spider could not cross. They found that web mass was much lighter in the colder conditions. We used some of their methods and ideas to design our own experiment, particularly their enclosure design.  

3 other containers with spiders will be placed in the cooler environment. An ice bucket and styrofoam box will be used to keep the temperature cool and the ice will be switched every 12 hours to maintain a consistent temperature. The last 3 containers will be heated by a heat lamp at roughly 30°C. All 9 spiders will be let be to make webs for 5 days. The spiders will be given food/water and the ice will be switched as needed. After 5 days, each plastic cup will be weighed.

To determine the web production in each environment, the plastic cup will be weighed at the end of the 5 days. The final weight and initial weight will be subtracted,  which will give us the weight of each spider web. The weights between the temperature groups will then be compared. Finally, a statistical test will be run to see if there is significance between the varying temperatures and spider web production.

Due to a new retrovirus that is killing domestic dogs at rapid speeds, only one vaccine can be made to save one breed. The Labrador Retriever, one of the most popular and beloved dog breeds, makes the most sense to save for many reasons. The Labrador Retriever does well in a variety of environments and  is known for being an overall good dog. They have a loyal, loveable, and happy personality that any family would be happy to have in their home. They make for good companions and are happiest when they are with you. It is not difficult to please Labrador Retrievers and it is easy to form a meaningful bond with this beautiful breed. Whether it is playing fetch outside or laying next to you on the couch, these dogs love being with you.