Sox9 Evolution PP

Submitted by maurabenson on Tue, 04/25/2017 - 23:56

 There is substantial evidence that Sox9 functions in the development of the male gonads in many species. Sox9 is mostly expressed in male gonads in the developmental stage of mouse fetuses, regulating the Mis gene which codes for production of the anti-mullerian hormone that stops the mullerian ducts from forming into the uterus and the fallopian tubes. Even in transgenic mice with two X chromosomes that were then engineered to induce the overexpression of Sox9, the mice still developed testes. However, in non-mammalian vertebrates, the Sox9 has a slightly different function. For example, in mice the Sox9 gene is expressed prior to the Mis gene, but in other species such as chicken, it is actually the opposite. This sugests that Sox9 is not essential to express Mis in chicken. Zebrafish also have two versions of the Sox9 gene where one version is expressed in the oocytes of the ovaries and the other is expressed in the sertoli cells in the testes. This does not happen in all other vertebrates.   Another difference is in the medaka, which are Japanese rice fish as well as vertebrates and they express the Sox9 in the oocytes but not in the gonads. They also have no Sox9 expression in their somatic cells but expression in their germ cells.

Sox9 Evolution

Submitted by maurabenson on Tue, 04/25/2017 - 23:49

The SOX9 gene is essential to the development of sex and skeletal development. It codes for a transcription that plays a part in multiple different pathways that contribute to formation of testes and cartilage. SRY (sex determining region on chromosome Y) works with Sox9 to begin development of the testes from the bipotential gonads, meaning they can either form ovaries or testes. It is also expressed with Coll2a1 which is a type 2 of collagen. Sox9 also contains the SRY-related HMG (high mobility group) box. Many species have a variation of this gene in their genomes, including mammals and birds. More specifically, the role of Sox9 in gonad differentiation is highly conserved in chicken, sea turtle and alligator, but can function differently in other vertebrates.

      There is substantial evidence that Sox9 functions to develop the male gonads. Sox9 is mostly expressed in male gonads in the developmental stage of mouse fetuses, regulating the Mis gene which codes for production of the anti-mullerian hormone that stops the mullerian ducts from forming into the uterus and the fallopian tubes. Even in transgenic mice with two X sex chromosomes was engineered to induce the overexpression of Sox9, the mice still developed testes. However, in non-mammalian vertebrates, the Sox9 has a slightly different function. For example, in mice the Sox9 gene is expressed prior to the Mis gene, but in other species such as chicken, it is actually the opposite. Zebrafish also have two versions of the Sox9 gene where one version is expressed in the oocytes of the ovaries and the other is expressed in the sertoli cells in the testes. This does not happen in all other vertebrates.   Another difference is in the medaka, which are Japanese rice fish as well as vertebrates and they express the Sox9 in the oocytes but not in the gonads. They also have no Sox9 expression in their somatic cells but expression in their germ cells.

      From this study and many others, there is sufficient evidence to conclude that while Sox9 plays a role in sexual determination in vertebrates, the mechanism for which this occurs can vary from species to species. This also would make sense due to the different types of sex determination, such as the XY system or ZZ/ZW for other species like chicken. Due to Sox9’s importance in skeletal formation, it also would make sense for the sequence  to be highly conserved in vertebrates in order to maintain proper bone (including spinal cord) formation. 

Poster Background

Submitted by maurabenson on Tue, 04/25/2017 - 23:47

 

Mosses are a multipurpose plant that provide services both ecologically and economically. Economically, mosses serve as fuel in some countries, as well as a landscaping tool. Ecologically, mosses help with insect shelter, absorbance of oil spills, and flood control(Rochefort). Unlike other plant species, mosses do not contain a vascular system, meaning they do not have vessels for conducting water. They are capable of uptaking water, through capillary action and absorbing it directly into their bodies (van Breemen). Mosses that live in a moist environment are  more susceptible to water absorption, therefore Sphagnum is expected to have the highest water capacity.

Sphagnum is a genus of moss that is adapted to wet and bog-like environments, and grows in large patches on a water’s surface (van Breemen). D. H. Boelter comments on the overall absorption of Sphagnum saying that the surface of the moss can absorb 95-100% water by volume at saturation. The leaf-like structures on the Sphagnum allow for high water absorbance in a small amount of time, making this experiment a valid way to test its absorbance capacity.    

    While Sphagnum has various environmental uses, Rochefort discusses the various functions Sphagnum can have in commercial materials. Through the last few decades it has been increasingly used as a buffer to fight flooding, a source of seeds after forest fires, a way to preserve artifacts, and a source for atmospheric regulation. These materials have positively affected aquatic areas especially during rainy seasons. With Sphagnum possessing the quality to be such a good absorbent, it poses the idea on whether it can be a better adsorbent material than other synthetic materials, such as sponges. Sponges could be potentially used as a synthetic material by humans to help in flood prevention in vulnerable environments.

This experiment was based off of the research of T.J.K Dilks who performed an experiment regarding the photosynthesis, respiration and water contents of bryophyte moss. In this experiment, the author took moss from outside a greenhouse to test the effects of water content on photosynthesis and respiration. In order to quantify how much water the bryophytes contained, they were all saturated and then dried to different water contents using an oven. Theses were verified with osmotic stress calculations using a Warburg apparatus. With this procedure in mind, methods were designed using the same principle, but an opposite approach.

D.W. Larson also had methods that are replicated in this experiment. This research analyzed the role of morphology in the wetting of lichens and mosses. Samples used were originally dried or contained 3-5% water weight, and time intervals were used to measure the absorbance of the lichen or moss. Some techniques were replicated for this experiment with both Sphagnum and other materials. Since Sphagnum is physiologically capable of absorbing high quantities of water, the research will be conducted in order to determine if it is the best material to control potential floods.

Poster Abstract

Submitted by maurabenson on Tue, 04/25/2017 - 23:46

This research tests samples of Sphagnum to determine which is the most favorable water absorbent in a controlled environment. Sphagnum is a multi purpose moss genus that is known for its high absorbance capacity. In recent years, Sphagnum has been developed to be used commercially as an absorbent board, which is turned into sanitary towels, and absorbents for oil spills and floods. Live and dead sphagnum were analyzed for their absorbance capacity. Materials were left in a controlled environment for a period of time and the absorbance was measured. The data was analyzed to conclude if live or dead Sphagnum was the most successful material for flood control.  

 

Landscape Ecology continued

Submitted by kmichaud on Tue, 04/25/2017 - 23:02

Though this patch is protected as conservation area, there is a significant amount of human traffic through the many walking trails. Organisms that inhabit this area must avoid frequent walkers, and their hiding places are rather limited considering the stretch of unbroken area. This particular patch is barely large enough to successfully harbor a population of large carnivores and a population of coyotes is well defined. It is frequented by populations of white tailed deer and other small mammals. The wetland areas and large streams running through the patch are also home to aquatic and semiaquatic organisms such as amphibians and fish. A population of brook trout are established in one stream that is an extension of the Asabet River. Since the patch is relatively irregularly shaped, animals that stray too close to the edge of the patch run the risk of collisions with cars and run-ins with humans. Wide expanses of farmland areas and busy roads block the safe passage to the next nearest undisturbed patch characterized by the Wachusett Reservoir to the North. Though inhabitants run the risk of death, they often stray beyond the patch in more suburban areas where forest cover is far more limited. White tailed deer and red foxes are two of the most frequently spotted travelers out of the conservation area. 

History of Canines

Submitted by mduque on Tue, 04/25/2017 - 19:29

In a study recently published, scientists examined the genomes of over a thousand dogs including more than 160 breeds to trace the relationship between breeds. The map revealed canines bred to perform similar functions do not necessarily share the same origin. The analysis hints at a canine that could have come over to the Americas thousands of years before Christopher Columbus arrived in the New World and around the time people crossed the Bering land bridge linking Alaska and Siberia. Somehow, these dogs disappeared when European and Asian dogs arrived in the Americas. This finding suggests that not all working or herding dogs are related. Researchers are continuing to look for genetic remains of these ancient canines in the DNA of modern American breeds but have found little evidence.

Primates

Submitted by scestero on Tue, 04/25/2017 - 16:21

Order Primate in the class mammalia is a group of mammals that appear to be very similar but are acctually very different. Primates are divided into two orders, Order Strepsrhini and Haplorhini. in order to tell them apart one must look at the eyes. First of all, all primates have forward facing eyes, this is a very distinct character of the primates. Order Haplorhini has a postorbital plate rather than just a bar. This means that their eyes are in a complete bone incased socket. These primates include all new and old world primates. The new world primates are the Platyrihini and the old world primates are Catarhini. New wolrd primates are primarily from the Americas while the old world primates are from Africa and Asia, aka the old world. Humans, having first evolved in africa are considered old world primates. Order Strepsrhini, can be identified by a lack of a postorbital plate in the eyes. These primates include lemurs and lorisis.

Antibiotics

Submitted by amprovost on Tue, 04/25/2017 - 12:29

Recently I experimented with antibiotic producing bacteria and antibiotic resistant bacteria in my microbiology lab. The results were as follows: 

Two experiments were performed in this laboratory, a Kirby-Bauer test and an enrichment of Streptomyces and testing for its Streptomyces antibiotic production.

            The expected result of the Kirby-Bauer test was that this test would indicate whether or not the bacteria used was resistant or susceptible to the antibiotic discs used. This experiment was performed on two plates, one using S. aureus and one using E. coli. Each bacteria was individually mixed in a tube of sterile saline, both becoming concentrated enough to equal the 0.5 McFarland standard. These solutions were then spread across Mueller-Hinton plates that then had antibiotic discs placed on them. The zones of inhibition were then measured to see if the bacteria were resistant or susceptible to the antibiotics. The results were as follows:

 

 Kirby-Bauer Results

Antibiotic

S. aureus resistant, susceptible, or intermediate

E. Coli resistant, susceptible, or intermediate

Ampicillin

Resistant

Susceptible

Ciprofloxacin

Susceptible

Susceptible

Colistin

N/A

Susceptible

Erythromycin

Intermediate

Intermediate

Gentamicin

N/A

Susceptible

Penicillin

Resistant

Resistant

Rifampin

Susceptible

Resistant

Trimethoprim/sulfanilamide

Susceptible

Susceptible

Vancomycin

Susceptible

N/A

 

            Whether a bacteria was resistant, susceptible, or intermediate was determined by measuring the zone of inhibition in millimeters around the antibiotic disc. The measurement ranges determining this were supplied by the manufacturer of the discs. The results of this experiment were as predicted, as these discs allowed us to determine levels of susceptibility.

            In the experiment regarding the isolation and enrichment of Streptomyces, it was predicted that Streptomyces would be able to be isolated from soil and would produce antibiotics, which would be displayed by zones of inhibition in a cross-streaking experiment.

            This experiment was performed by doing two things with a soil suspension. First, the suspension was streaked onto a casein-starch plate. Second, this suspension was diluted by taking one milliliter of suspension and transferring it into nine milliliters of sterile saline. This new solution was then also streaked onto a separate casein-starch plate. After the Streptomyces were isolated, three individual colonies were taken and streaked in a heavy band across the top quarter of an antibiotic-test plate. These heavy bands were then cross-streaked with S. aureus, E. faecalis, K. pneumoniae, and A. hydrophila. A control plate with all of these organisms and no Streptomyces, to show what uninhibited growth would look like. After allowing for these organisms to grow, there appeared to be no inhibition from Streptomyces, as the cross-streaked grew perfectly across the entire area inoculated, looking quite similar to the streaks in the control. One possible explanation for this is that Streptomyces does not produce any antibiotics that affect these types of organisms. Another possible explanation for this is simply that the Streptomyces were not given enough time to produce antibiotics, and perhaps the expected results would have been displayed had the plates been left undisturbed for a longer period of time.

 

Fungi

Submitted by amprovost on Tue, 04/25/2017 - 11:48

I recently experimented with growing fungi in my microbiology lab. My results were as follows 

This lab had two separate experiments, one was the cultivation of fungus on both nutrient rich and nutrient poor agar, and one was on sugar fermentation by Saccharomyces cerevisiae.

            The expected results of the experiment on nutrient rich v. nutrient poor agar was that the fungus would grow better on the nutrient rich agar, as a better food source was available. The experiment was performed by inoculating a plate of FPDA (nutrient rich agar) and a plate of PCA (nutrient poor) with Fusarium. The results of this experiment showed a complete absence of Fusarium on the nutrient poor agar, and a large lawn covering about 75% percent of the nutrient rich agar. This lawn was red in the very center, with a white ring making up the outer half of the fungus. The expected results were confirmed by this conclusion,

            In the experiment with S. cerevisiae, the expected results were that glucose and sucrose would ferment, but that lactose would not. This experiment was performed by inoculating tubes of purple broth glucose, purple broth sucrose, and purple broth lactose with S. cerevisiae. Any sugars that were fermented would produce acidic byproducts, which would turn the tubes from purple to yellow. Each tube also contained a Durham tube, which would catch any gas produced in fermentation such as carbon dioxide; so one would be able to see if there were any gaseous byproducts. The results showed that S. cerevisiae is able to ferment glucose and produced a gaseous byproduct, but is not able to ferment either sucrose or lactose.

            The expected results did not match the results as sucrose was unable to be fermented. It was predicted that sucrose would be fermented as sucrose is a common sugar in many plants that share an environment with S. cerevisiae. The most likely explanation of this is simply that S. cerevisiae has no evolved mechanism to break down sucrose and must derive its energy from another food source in the environment, such as glucose.

journal

Submitted by jiadam on Tue, 04/25/2017 - 11:45

Meselson-Stahl Experiment

This experiment used 2 different nitrogens because nitrogen is a huge component of nucleotides, 14N and 15N. 14N is the light nitrogen and is the most abundant on earth. This  makes DNA less dense. 15N is the heavy nitrogen which is not as abundant and more dense. They used two different nitrogens so that they can be separated by density. 15N was placed in E.coli and E.coli replicated the DNA. Using density centrifugation, they were able to see the amount of nitrogen and which nitrogen it was because of the differences in density. After the first round of replication, the DNA was in the middle of the test tube which can indicate semi conservative or dispersive because each DNA molecule is half 14N and half 15N. After the second round of replication, one set of daughter cells were intermediate(half 14N/15N) and the other was lighter which answer the question between semiconservative and dispersive. DNA is replicated semiconservatively. After numerous rounds, the amount of 14N was significantly more than 15N.

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