Monday, April 27, 2009

Rubby Puppy

This is a beagle puppy named Ruppy, which means "Rubby Puppy". This is the world's first transgenic cloned puppy. Trandgenic means that this puppy has genes from another animal and its genetic code was deliberately modified. This puppy's uniqueness was not derived from a natural mutation. Under natural light this puppy looks normal, but when this puppy is placed under an ultraviolet light it glows in the dark.

Ruppy is one puppy in a littler of five puppies who are genetically engineered to glow a deep red color under ultraviolet lights by producing fluorescent proteins. The long lifespan and reproductive cycles of dogs make them more appealing to researchers because they are more relevant to human fertility than mice are.

These puppies were created by a team led by Byeong-Chun Lee of Seoul National University in South Korea. There was only seven successful pregnancies from three hundred and fourty four specially cloned embryos which were implanted into twenty dogs. One fetus died half way through term and an eleven week old puppry died of pneumonia. Only five puupies survived which all have a red glow. These puppies have grown up and are now producing their own fluorescent puppies.

The red glow came from cloned cells that were inserted with a red fluorescent gene that sea anemones produce. This fluorescent gene was transferred into each dog's egg cell. This was done by using a retrovirus. The scientists were unable to control where this virus was inserted into the genes.

Ruppy was created by Lee and his team by infecting dog fibroblast cells with a virus that inserted a fluorescent gene into the cell's nucleus. This nucleus that contained the virus was then transferred into another dog's cell after the nucleus had been removed from that cell. The researchers then left this cell to divide in a Petri dish for a few hours followed by implanting the cloned embryo into a surrogate mother.

There are some probelms with creating trangenic dogs. One issue is the negative public perceptions and responses. It is also expensive to care for laboratory-reared dogs, much more expensive than mice. There is a low efficiency of cloning, in this case about 1.7 per cent of the embryos implanted came to term. Another issue is not being able to control where in the nuclear DNA a foreign gene lands.

Researchers now have been able to preform "knockout" procedures only in mice and rats. This is a problem for researchers dealing with dogs because not being able to knockout specific genes prevents researchers from choosing what genes are deleted or engeneering dogs that produce mutant forms of a gene.

Transgenesis is a long, laborious, slow, expensive process, but researches want to use this process in dogs for medical research. They want to use dogs for models of human disease. One member of Byeong Chun Lee's team, CheMyong Ko, stated, "The next step is to generate a true disease model."


I am going to do a presentation on the swine flu. This is a huge epidemic which just resently enetered the United States.

Monday, April 20, 2009


I would to present on HIV drug therapy for my presentation.

presentation topic

I think I'll talk about nanotechnology this wednesday. Yeah, that sounds like fun. Any votes of dissension?

GRE ftw!

Today I'm going to recall one of the sample GRE exam questions that I may or may not have missed. This question has to do with biotic potential. The question was: "What organism has the greatest biotic potential?" The possible answers (multiple choice questions) were asexual organisms, sexual organisms, rodents, or something silly that wasn't the right answer. The correct answer here is rodents (or at least that's what the answer key would acceptas correct).

Biotic potential is a term describing the maximum capacity an organism (or group of organisms for that matter) to where said population can reproduce while under optimum environmental conditions. Rodents then obviously do fit the bill here, as they do reproduce at a relatively high rate. However, single-celled asexual organisms can undergo mitotic divisions much faster than rodents can pass through its respective fetal developmental stages. So I'm not entirely sure why rodents were chosen over the asexual organisms answer. However, I can see how rodents generally do have "a high biotic potential."

Wednesday, April 8, 2009

Oh, pretty colors!

I've always enjoyed reading about the gamut of analytical techniques employed to investigate the intricate nature of things. I recently read an article from summarizing the work of Gauthier et al. on their study of the way high-resolution retinal impulses are transmitted to (and eventually translated by)the brain. I would imagine approaching this problem would seem to most an abstract attempt at elucidating human perception; however, this particular study generated some pretty straight-forward illustrations to help explain their conclusions. The authors made mosaic illustrations depicting how individual neural impulses collected as if pieces of a jigsaw puzzle. Each neural impulse was correlated to a "receptive field" or RF. As stated in their methods section, "RFs were mapped by computing the spike-triggered average (STA) stimulus obtained in the presence of a white noise stimulus." Then through some complicated mathematical prodding, Gauthier et al. gave us some pretty pictures (like the one above) to show us how high-resolution retinal signals accumulate for translation by the brain. How neat is that!?

Wednesday, March 25, 2009


While taking a practice GRE style subject test, I stumbled upon a question asking which of the organisms is not photosynthetic. My choices were cyanobacteria, diatoms, dinoflagellates, foraminifera, and rhodophyta.

I selected diatoms, because from what I remembered I thought that they were creatures that lived in rocky substances or soils, and have a crystallin look to the organism.

A first look at the organism on the left does not reveal anything that would lead it to be photosynthetic, but it is. They do indeed have chloroplasts and are photosynthetic.

The other answers that eliminated are cyanobacteria, dinoflagellates, and Rhodophyta. I eliminated cyanobacteria because I knew that organism got its name from having a cyan color, predominately because it is very photosynthetic. It is a cool organism that is a bacteria and photosynthetic at the same time. I also eliminated dinoflagellates because I distinctively remember that organism being photosynthetic. Under a light microscope it is easy to see the green color from the chloroplasts withiin that organism. The last organism that I eliminated was Rhodophyta. I remembered that this group was a reddish brown algae, and I believe all algae is photosythetic.

I was left with diatoms and Foraminifera. So what exactly is Foraminifera? They are a group of amoeboid protists that undergo a process where they take in algae, and then can temporarily use the plastids for photosynthesis and can be used by the Foraminifera. So in the end, the "forams" are not necessarily photosynthetic in it themselves, but they can use photosynthesis through algae that they take in.

I obviously did not know all of this come time of the question, but the more I look at it, it seems as if it is somewhat of a confusing question, because the "forams" at certain points are photosynthetic, but without the algae they are not. Someone that knows a lot about all five of the organisms in the question might nail this problem, but others may end up arguing with it.