DVD Evolution: Constant Change and Common Threads

link:http://www.hhmi.org/biointeractive/media/breeding_corn-lg.wmv

The above link will take you to the video clip referenced for the post below.

DVD Evolution: Constant Change and Common Threads

In this video, we learn how the art of manipulating phenotypes through selective breeding in dogs is used to manipulate the gene pool. Over 10,000 years ago, wolves started to live among humans, and the selective breeding began. By actually choosing which dogs have the desired traits that are needed to perform tasks such as hunting, herding, guarding and many others, humans have been able to manipulate and determine the traits of those down the bloodline. The same hold true for charactaristice such as size, coat and color, as well as many other traits or charactaristics.

Salmonella Infection Demonstration

In this video, Dr. Finlay is demonstrating how Salmonella (a common bacteria associated with food poisoning) invades a cell by using a marble, plastic wrap, and some yellow gelatin. The marble represented the Salmonella bacterium, the plastic wrap represented the cell membrane and the yellow gelatin represented the cytoplasm of the cell. Dr. Finlay had a volunteer to help represent how Salmonella will infect a cell by pushing through the cell membrane and getting inside the cytoplasm.
Salmonella is a gram negative bacterium which we learned in class that the bacterial cell wall structure consists of two phospholipid layers, a peptidoglycan layer and LPS. When we perform a Gram stain the cell will appear to be pink.

http://www.hhmi.org/biointeractive/media/jello_salmonella-lg.mov

Mr. Lincoln Glows

In this video clip titiled Mr. Lincoln Glows, Mr. Lincoln refers to a copper penny that is used as a catalyst to speed up a reaction. In this case the reaction is the decomposition of a simple organic molecule called acetone. The normal decomposition of acetone happens very slowly and so the acetone would evaporate in the room long before you could get any significant breakage of the acetone. So to speed up this reaction, the copper penny is heated over a flame and then placed in the beaker just above the acetone. With the copper held in place above the acetone, the acetone molcules land on the copper's surface and that is how it speeds up the decomposition of acetone into 2 other organic molecules (ketene and methane). With the presence of oxygen, combustion takes place burning the small organic molecules to produce carbon dioxide (CO2), water (H2O), and heat which keeps the copper catalyst hot so it continues to participate in the breakdown of acetone. The penny will glow for about an hour as it is held above the acetone.
As we learned in our microbiolgy class, a catalyst is a substance that remains unchanged while speeding up a reaction. This is a good example of how the copper penny is used as a catalyst to speed up the reaction but does not directly participate in the reaction and is not consumed, therefore it remains remains unchanged while speeding up the reaction.

This link will take you directly to the video.
http://www.hhmi.org/biointeractive/media/mrlincoln-lg.mov

This link will direct you to the page the video is on, scroll down to the bottom of the page and the video is called Mr. Lincoln Glows.
http://www.hhmi.org/biointeractive/video/index.html

p53 molecule

The animation I watched was about a p53 molecule. It is a molecule protein which binds to specific sequences next to the genes which it controls. There is a p53 molecule binding to its binding site. It recruits a RNA polymerase which is an enzyme that makes a new RNa strand using a DNA template. p53 molecule initiates the transcription of mRNA. It relates to the course, because we just had an exam on DNA transcription.
http://www.hhmi.org/biointeractive/media/p53-lg.mov

The Lifecycle of Malaria. Human Host

The video The Lifecycle of Malaria. Human Host by Drew Berry shows us how infected with malaria mosquito can vey fast spread an infectin among people. When a malaria-carrying mosquito bites a human, it injects a saliva with malarian parasite in human body and parasite enter in blood stream. With blood parasites enter a liver cell where it multiply its DNA over and over; so, one infected liver cell can create thousands of new parasites. They now are intering to red blood cell (RBC). Inside of RBC parasites hide from body immynsystem and replicate more and more. Finally, infected cell becomes mature and it bursts, sending more parasites in blood stream. And cycle begins again with thousands of parasites now.
Human infected by malaria suffer from fever, coma, convulsions, loss of blood due to damage of RBC, and brain damage. This year 10 % of population all over the world were infected by this disease, most of them were pregnant woman and children under the age of 5. We will study this disease along with other infection diseases and their causes later this semester.
http://hhmi.org/biointeractive/disease/malaria_anim/malaria-human.html

E. coli Infection Strategy

I watched an animation on E. coli infection strategy. In this animation it shows how the molecular tricks that an infectious strain of E. Coli uses to infect your gut. E.coli are very common, and generally harmless bacteria, but certain less-common strains of E. Coli can cause serious illness. In this animation it shows how a single E. coli bacterium sticks on to the surface of an intestinal epithelial cell using a long, pili. Once it comes in contact with the bacterium, the microvilli disappears and the bacterium comes into closer contact with the intestinal surface. Then the bacterium injects receptor proteins into the intestinal cell that is invading. Intestinal cell forms pedestal for bacterium, and infection follows. Once many bacteria have adhered to the intestinal lining, symptoms of the infection (diarrhea) commence. I found this animation very interesting because it happened once that my cousin got his gut infected, and had diarrhea and all, so i really wanted to know what infects it and what happens when it does. This animation is really revelant to Micribiology class, because we have been working with E. coli bacteria a lot and i think it is a very cool bacteria to study, especially because it is Mr. Kubo's favorite!

http://www.hhmi.org/biointeractive/disease/animations.html#ecoli

DNA Replication (basic detail)

I watched a short video about DNA Replication. This video eplains how the DNA is replicated from one DNA strand into two new DNA strands. First, the helicase unwinds the DNA molecule at a very fast speed("like a jet"--as they said). Then one DNA strand is copied continuously into a new DNA strand, while the other one si copied backwards one section at a time.
This topic relates directly to microbiology, because we were just studying about DNA Replication. After watching this video, I have a better visual idea of how DNA replicates into two new DNA molecules.
http://www.hhmi.org/biointeractive/media/DNAi_replication_vo1-lg.mov

Penecillin acting on bacteria

http://www.hhmi.org/biointeractive/video/index.html

The video clip on how Penecillin acts on bacteria was very interesting and relevant to our Microbiology class because the bacteria they used in the video was "E.Coli." Since we have been studying and working with E.Coli bacteria, it was very interesting to actually watch how Penicillin acts and pokes holes in the cell wall of the E.Coli bacteria. Once the penicillin poked the bacteria, they would literally pop. During the video, you can see the bacteria shrivel up and turn a light color as they died.

Size anologies of Bacteria and Viruses

This short video clip presents various analogies so we can better visualize the size of viruses and bacteria. It was said that viruses and bacteria are submicroscopic and that therefore we cannot see them with the naked eye. There is a big difference in size between them. In order to get a sense of their scale, we can take the human body to represent a single cell. Then the large viruses, like those of the smallpox, would be the size of a battery, and the small viruses, such as polio, the size of a tiny tablet, while a million bacteria would be the size of one big room. When measured by a ruler that is divided in inches, centimeters and millimeters, the bacteria are the size of 0.001 mm (or one thousandth of a millimeter). We can never see a single organism (bacterium) but only the whole colony. Although they are very tiny, they play a significant role in our lives. In our microbiology class, we learned that microbes or microorganisms are organisms that are generally too small to be detected with a naked eye and therefore can only be seen with a microscope. Plants, animals and humans all need them for survival and as such they are an integral part of our lives. Moreover, billions of them live in our bodies and we need them in order to stay healthy. Because they can also cause diseases, it is essential for us to understand how microbes work, how they can affect our health, and how we can use them for our benefit. Since we depend on them, we need to understand the biological processes of microbes that are common to all organisms and our ecosystem. We also learned that they can be beneficial or pathogenic; luckily for us, there are more beneficial microbes than pathogenic (less than 1%). It was also gratifying to learn that microorganisms are used in making wine, yogurt, alcohol, cheese, and sour kraut. On the other hand, medical science has developed antibiotics, vaccines and antiseptic methods to fight pathogenic microbes. Thus, handwashing was always considered important (to reduce infections), but now that we know more about microbes, it is crucial.

http://www.hhmi.org/biointeractive/media/size_analogies-lg.mov

HIV's origins in Africa

http://www.hhmi.org/biointeractive/video/index.html

In this video, Dr. Beatrice Hahn explains the origins of HIV in Africa. She explained that her research and studies have led to the conclusion that HIV was introduced into the human population through "cross-species transmission." However, she said that cross-species transmission alone is not sufficient enough to cause an epidemic. There had to be other contributing factors. Remarkably, there are primates Sub-Saharan Africa who are already naturally infected, yet do not show any signs of disease or immunodeficiency. But Dr. Hahn has traced HIV's roots to these very distinctive chimp communities and has traced its course from South East Cameroon, to Kinshasa, over the Congo river and into East Africa, specifically Uganda, where it was first clinically discovered.

This video relates to our class as we will be studying HIV and it's pathogenesis, as we have been with other infectious bacteria such as E.Coli and Streptococcus.

Genetic Engineering

The video " Genetic Engineering" is a common technique to insert a new gene into a loop of bacterial DNA called plasmid. This is done by cutting the plasmid DNA with a restriction enzyme such as Eco RI, which allows a new piece of DNA to be inserted. The enzyme allows to run along group of a double helix, and scans for the base letters sequence GAATTC. Then the enzyme cut the plasmid at the specific point allowing a new piece of DNA to be inserted. As the plasmid is cut, Eco RI leaves a sticky-ended which helps a new gene to attach. After that the joint are stitched together by DNA ligase. In addition, the genetic engineering bacteria is growth in culture medium, so large number of bacteria can be produced very quickly. Now the genetically engineered bacteria will manufacture any protein gene coded for, so the designed product is made.
Last but not least, in our microbiology class we have learned that DNA ligase is an enzyme that seals gaps between DNA segments to form a continous DNA strand. However, DNA ligase is only one of enzymes which takes part in DNA replication, there are still more types of enzymes which we have learned in last chapter, such as DNA helicase, DNA polymerase and primase. Moreover, we will learn abour the genetic engineering in next chapter.
http://www.hhmi.org/biointeractive/media/DNAi_genetic_eng-lg.mov

Penicillin Acting on Bacteria

This short movie demostrates now a anit-bacterial ,Penicillin, acts on a gram negative cell E.Coli. When penicillin is used on e.coli the bacteria lengths and then it pops. Pencillin acts on the outer layer of the cell membrane. Penicillin allows the cell to lengthen but does not allow the cell to divide to make more new bacterial cells. Instead, the cell pops, killing the bacterial. This relates to the class because we have learnt that a bacteria's cell protects the nucleus inside the cell. However, if the cell wall dies then the bacteria will die to. http://www.hhmi.org/biointeractive/media/penicillin-lg.mov