For the final lab assignment, we, the Developmental Biology students, used wire loops to extract bubbles from a beaker filled with a Dawn dish detergent, glycerol and water solution and produce well-formed bubbles on a petri dish. Photographs were taken of all attempts, and these are the best I was able to produce (they are presented together in one word document because they images become corrupted when the type of image they were formatted as was uploaded):
I read an evo-devo article recently that I found quite interesting.
It can be found here:
Dr. Stuart A. Newman, professor of cell biology and anatomy at New York Medical College has proposed a concept that could drastically alter the current theory of evolution. While evolution is commonly thought to have happened very gradually, by small steps, Newman has come upon an alternative model that may give some insight into early animal evolution. Animals are developed with specific 'morphological motifs.' Embryos develop with specific arrangements of discrete tissue types (with non-mixing layers) and at certain points form distinct segments. As embryos develop, they fold, elongate and form appendages. This theme is true of all animals.
What Newman proposes is that the origination of the structural motifs of animal form was predictable and relatively sudden, with abrupt morphological transformations favored during the early period of animal evolution. His model I based upon inferences about the genetics of the single-celled ancestors of the animals. The single celled organisms are believed to have contained genes of the developmental-genetic toolkit we have come back to so often in class. The products of these genes enabled the ancestral clusters to produce the characteristic motifs by harnessing the middle-scale physical effects, described by Newman as physical effects or governing constraints on how single cellular organisms may orient themselves together. In this way, the same basic structural motifs are present in all animals, and the same toolkit genes serve the same, or similar, functions.
In lab we are studying the reproduction and development of fruit flies, Drosophila melanogaster. For this, I observed the behavior of the mating rituals. I am very frustrated to report that since I was attempting to use unfamiliar technology and was required to convert what video footage I was able to get between various formats, as well as transfer the information between several computers, the data was corrupted in a way that has prevented me from opening or uploading the file on my computer.
Besides, I was only able to record about 5 of footage since it was difficult to correctly anesthetize the flies within overshooting and killing them, or at least making them so sluggish that they displayed no interest in each other. I observed a brief instance I had hoped to share in which one male and one female courted each other on the agar medium. The male displayed an interesting behavior; after approaching the female, he flapped hiss wings fiercely. Upon first documenting this, I thought the male was performing some display of strength or virility, but through text research I have learned that this is a method by which the male serenades the female. Apparently, the male can beat his wings in such a way that he will produce a series of pleasing tones for the virgin female to entice her to copulate. Sadly for this male, no copulation took place as the female curiously did not show interest.
I read an article that related different embryo behavior and growth to the amount of activity mares (female horses), i.e., the amount of exercise they get.
The article can be found here: http://www.journalofanimalscience.org/content/90/11/3770
In a practice known as embryo transfer, female competitive race horses are fertilized via traditional copulating with a male, and the very young embryo is then transferred 7-9 days later into a non-competing female. This allows racing females to compete even in the breeding season when breeders hope to breed them with males to produce a new generation of competitors.
Researchers in Florida set about determining the effects of exercising mares during the 'periovulatory period,' or the period in which an oocyte is discharged from the graafian follicles of the ovary, by exercising females at this stage at different amounts--none, some, and full--and analyzing embryo recovering rates. The concern is that competing horses, who are exercising strenuously, will produce inferior embryos that may not survive the transfer into another female.
In the study, the researchers found that exercise led to reduced embryo recovery rates when compared to the recovery rates of non-exercising females. They hypothesized that reduced hormone concentrations linked to exercise, as shown by blood analysis, may affect the competency, or structural integrity, of the female's oocytes (eggs). In particular, the stress of exercise increased cortisol amounts, which have been shown to have effects of reproduction. Compromised oocytes may be less likely to become fertilized, and if fertilized, the resulting embryos may not develop correctly.
I read a very interesting article about nematodes, which I wanted to read since we are working with nematodes in lab.
The popular science article is located here:
The full primary research report, found in the journal, Cell, can be found here:
Apparently, there are two species of worms, Caenorhabditis elegans and Pristionchus pacificus, that have the exact same twenty neurons that control the activity of the foregut. Apparently, it seems that the same set of genes causes the same neurons to develop--they share the same cells--but the way they are connected is drastically different, so much so that they can digest different types of organisms for food. While Caenorhabditis elegans can digest bacteria, Pristionchus pacificus, evidently, is able to eat other worms.
The synapses were found to be wired quite differently, and it seems that there is a difference is the way information moves through the neural system. In Pristionchus pacificus, neral signals pass through more cells before reaching the muscles of the foregut, which indicates that more complex motor functions are being performed; this could attribute to the ability of the worm to actually consume and digest another worm.
Lab 1 Photos
For this first week in lab, my classmates and I practiced using the Wild M5 dissecting scope and the Leica DMLB research cope to take picture of different slide of the embryos of organisms at different stages of development.
The above photograph was taken at 10x magnification of the Leica DMLB research scope with a P2 dark filter. It shows the very early gastrula of an amphioxis (the slide title says gastrula, but it must be in the early stage of gastrulation since it has yet to fold in upon itself). We can see the vegetal half flattening at the bottom of the photo.
The above photograph was taken at 5X magnification with no filters (bright field) on the Wild M5 dissecting scope. It shows a developing tunicate, with its stage of development unspecified by the slide title.