Physiological and Genetic Identification of Micrococcus luteus Isolated from the Hind Foot of a Chinchilla
Here is the link to my Lab Report. Thanks for a wonderful semester! Wishing everyone a great summer!
Here is the link to my Lab Report. Thanks for a wonderful semester! Wishing everyone a great summer!
My name is Kjersten Williams. For my art project, I decided to go with mixed media. I constructed the microbes’ background environments out of paper and colored pencil, and made the microbes themselves out of modeling clay, giving the project a bit of visual depth. For my subject, I decided to focus on a specific group of microbes: the temperature extremophiles. I wanted to showcase the variety of different morphologies and habitats of these microbes (through the relatively accurate depiction of the microbes and their respective environments), while also making a statement against the general belief that all microbes are “bad’ (hence, the added shaky eyes to make them cuter and more personable). These microbes live in environments which would be deemed uninhabitable to the majority of life forms on Earth. Due to their resilience and adaptability, they represent the type of organism which astrobiologists may be most likely to find on other planets!
There are a couple mesophiles included for the sake of contrast. The microbes represented are: Chloroflexus aurantiacus (the red snake-like thermophilic bacterium represented against the background of a hot spring area), Methanopyrus kandleri (the blue, rod-shaped hyperthermophilic archaea set against the background of hydrothermal vents), Deinococcus radiodurans (a mesophilic bacteria represented by the green tetrad set against the forest background), Acidithiobacillus thiooxidans (a mesophilic bacterium represented by the purple, rod-shaped microbe with the pink flagellum), Psychrobacter arcticus (the blue diploid psychrophilic coccobacillus bacterium with pink spots, which is set against the aquatic background underneath the ice layers), and Planococcus halocryophilus (the blue-green diploid cocci bacterium set against the polar background).
— Article and link: “Too Clean for Our Children’s Good? The Checkup’ by Perri Klass, MD, The New York Times, April 17, 2017.
— Summary: This article talks about the many various ways in which our children are protected from interaction with microbes, including giving birth by caesarian section, bottle-feeding, and possible exposure to antibiotics. Such protection on the one hand affords protection from disease but on the other hand offers greater risk that children may experience complications of the “built environment.’ It is a concern that living in such a clean, controlled environment could lead to an underdeveloped immune system and subsequent health problems which may have otherwise been avoidable had the body been exposed to a diverse array of microbes at a young age. In order to combat this problem, it is recommended that young children be introduced to these microbes in the outside environment through “controlled exposures’ in the form of either “natural exposure’ consisting of interaction with their environment or through a type of vaccine yet to be developed.
— Connections: This article include discussion of the development of the human microbiome, its importance in the overall health of an individual, the avenues by which children are typically first exposed to microbes, and also the concept of vaccination with microbes in order to improve health. All of these are topics which have been mentioned or discussed over the course of the semester.
— Critical analysis: I liked the contrast that the author provided between the microbes found outdoors as opposed to those found within the “built environment.’ While I had naturally assumed that the inside of a house or apartment may be “cleaner’ than the outside world, I had not given much thought to the members of the microbial populations to be found in each of the two environments; in reality, the inside of a dwelling is not necessarily any more microbe-free than the outside, it is instead simply inhabited by a different, and possibly narrower, variety of microbes. I did not detect anything scientifically inaccurate or confusing in this article, and think that it did perform an adequate job in relaying this information to the public. The author did not get too technical in any of their explanations, yet clearly stated the anticipated problem, reasons behind that belief, and also the possible solutions to the problem.
— Question: Are researchers suspecting that the health problems mentioned are primarily due to inadequate exposure to pathogenic bacteria? Or do interactions with the non-pathogenic bacteria also play a role in shaping the immune system of children? What kinds of “natural exposures’ are parents advised to pursue in order to assist their child’s immune system to develop properly?
— Article and link: “New HIV reservoir discovered: Findings reveal a second target for cure research’, Science Daily (it should be noted that the article on Science Daily sites the University of North Carolina Health Care as their source and mentions that the original findings were published in Nature Medicine on this same date), April 17, 2017.
— Summary: This article describes scientists’ recent discovery that there is another cell within the human body which can act as a reservoir for HIV in addition to T cells: the macrophage. This discovery that macrophages are susceptible to infection by HIV is very important to current research focusing on the treatment of AIDS: this tells researchers that a successful treatment or cure would have to be effective in ridding the virus from both T cells and macrophages. One investigation found that viral replication within macrophages is effectively repressed when antiretroviral therapy is administered; however, the study also found that this effect is only temporary. Following treatment conclusion, macrophages still act as reservoirs for the virus and therefore remain capable of reinfecting the host. More research must be conducted in order to find the most effective way to resolve HIV infection of macrophage cells.
— Connections: This relates to information we have discussed over the course of the semester in that it discusses a virus, HIV, and also cells involved in the immune response (T cells and macrophages). It also relates to the resolution of disease through treatment and also the ways in which viral cells can find ways to persist inside a host even following treatment; both of these are subjects which were briefly touched on in class this semester.
— Critical analysis: I found it interesting to learn that HIV can also afflict host macrophage cells in addition to the host’s T cells. It has been known for some time that HIV targets T cells, but I had not heard of any other types of cells being specifically targeted by the virus. I also found it interesting that the antiretroviral therapy typically used in treating HIV infections in T cells does not work effectively on macrophages. I expect that the story is scientifically accurate as I have not seen indications to the contrary. I also did not find anything confusing in the article that would need to be corrected. I believe that they did a good job in relating this news; it seemed as though they kept their audience in mind, and focused on relating the pertinent details and implications of this discovery without making the article too technical for those who may not have the background to understand a technical explanation.
— Question: What are the most significant differences in terms of structure between T cells and macrophages which would cause antiretroviral therapeutic (ART) agents to be effective on T cells but ineffective in macrophages? Which ART’s were tested on the macrophages? What is their mechanism of action? Are scientists already aware of the specific reason that the ART does not work on macrophages?
— Article and link: “Zika-Fighting Sterile Mosquitoes Released Near Key West’, NBC News, April 19, 2017.
— Summary: This article aims to describe the testing of new experimental methods for the reduction of Aedes aegypti mosquito populations, a species which has been previously linked to the spread of multiple diseases, including the Zika virus. The ultimate goal of this testing is to control the spread of the Zika virus through controlling these insect vector populations. One such method has recently been tested in Key West, Florida, where lab-raised male mosquitoes infected with Wolbachia spp. of bacterium were released into habitats known to harbor populations of Aedes aegypti. The lab-raised male mosquitoes will breed with the wild female mosquitoes; however, due to the Wolbachia spp. carried by the male parent, the young produced by this coupling cannot survive to adulthood. While this method involves the use of microbes, there is another technique mentioned which instead involves genetic modification of lab-raised male mosquitoes to obtain a similar result.
— Connections: This article related to the material in class through its association with Zika virus, which was covered both in our course material and also in the guest lecture given by Dan Stinchcomb. The use of these microbes by humans to alter a detrimental aspect of an environment is also an example of microbes functioning in environmental bioremediation, another topic covered in class.
— Critical analysis: I found this method for mosquito population control extremely interesting. We had learned in class that certain microbes can be used to confer certain health benefits to a host organism through the transfer of particular genes, but I had not yet heard much of this particular strategy involving using members of a population as hosts for the microbe with the aim of stopping the spread of a disease from an insect vector to a human population. Both this method as well as the genetic engineering process mentioned towards the end of the article, if such methods prove effective in their goal and also harmless to the environment, would be extremely useful in inhibiting the spread of the Zika virus and thereby preventing further human infections.
This article was written in such a way as to inform the general public. As such, the scientific details and mechanisms behind the ideas discussed are not mentioned in great detail. In terms of the limited scientific details provided, I believe the article was scientifically accurate, though somewhat vague. The explanation of the science involved was somewhat simplified, and I did not detect any confusing aspects. While I personally feel that they could have included more detail behind the processes mentioned, I can see that the inclusion of too much detail could have been confusing to someone not well-versed in biological concepts. I think the article adequately communicated the highlights of the science to the public, as it stuck to the main ideas and results of the testing in an attempt to be clear and to communicate their ideas effectively.
— Question: What is the mechanism by which Wolbachia spp. inhibits the development of the next generation of mosquito? Would the inhibition of mosquito populations through such methods reduce their numbers to the point where other organisms in the food chain might be affected (most specifically those organisms in the food chain which utilize mosquitoes as a food source)? In reference to the genetic engineering method for the control of mosquito population, what is altered or added in the genome of the mosquitoes in order to obtain the desired effect?
Eric Collins presented a seminar on some of the specific aspects of oceanography that he studies: the flow of water and ice through the Arctic Ocean and how the structure of life in the Arctic Ocean is affected by the different characteristics of this flow. He noted that the presence of ice in sea water affects the chemical composition of the water. As ice freezes, it releases salts into the water, which then play a role in forming layers within the Arctic seawater possessing different gradients of both salinity and temperature; a side effect of this process is that water currents which circulate through the arctic emerge both colder and fresher than before as they now contain sea ice. Changes in the salinity of seawater as well as the formation of different gradients of salinity and temperature in the ocean are all aspects which impact microbe survivability and the ways in which microbes interact with each other and their environment. He also mentioned that the input of freshwater into the arctic from multiple ocean currents, while not a significant volume compared to that of the total volume of water which regularly circulates through the Arctic, plays an important role in the microbiological structure of the Arctic Ocean.
Relation to Microbiology and Questions:
Currently, much of the sea ice in the arctic is very young: less than 10 years old. The melting of arctic ice changes the composition of the ice and water in the Arctic, allows light to reach further into the sea water, precipitates an earlier spring in the region, contributes to an increased abundance of plankton, and results in less ice for animals, such as polar bears, to live on. These changes also affect the habitats in which microbes in this region live. Microbe content in water and ice differs geographically as well as between the different layers of water and different types of ice found in the Arctic. There are differences between microbes found in sea water, young sea ice, and old sea ice; such differences indicate that loss of or changes to the composition and abundance of these habitats would likely result in extinction for those microbes which require the specific conditions provided by each type of environment. Definite biogeography and special patterns also exist in terms of microbe presence in the water currents and sources which contribute to water flow through the Arctic Ocean.
Some questions which this lecture brought to mind are: can the various species of microbes found in the Arctic Ocean all be traced back to the incoming currents? Are there some microbes which are only found in the Arctic Ocean? Eric Collins also mentions how different microbes are found within the different temperature and salinity layers within Arctic seawater as well as in old and young sea ice in the Arctic regions. Does this differentiation based upon salinity and temperature also apply to the many viruses which live in the ocean? I am very curious about this last question in particular after learning in lecture that there are so many viruses in the ocean!
My artistic intent was to use the colors of microbes available to make images of common things we see in everyday life which all have a tie to microbes. Microbes play a significant role, both out in nature as well as within other organisms. Two of my plates had a nature theme (the tree was meant to be a weeping birch and the other a mixture of flowers and leaves) while the other was meant to be an emoticon/person. While the Tryptic Soy Agar (TSA) and MacConkey (MAC) Agar paintings turned out as I meant them to, I was envisioning different colors for the Eosin Methylene Blue (EMB) plate. However, I think this difference in color expectation and result is due to the fact that I was likely envisioning how the colors of the three microbes would have turned out using a TSA plate.
On the TSA plate, the bacterium grow and display their natural coloring, as evidenced by the green/yellow coloration of the P. aeruginosa composing the leaves of the tree and the white coloration of the S. enteritis used for the bark.
On the MAC plate, I used the fact that this agar is differential according to a bacterium’s ability to ferment lactose. To form yellow leaves and flower centers, I used P. mirabilis, which does not ferment lactose and thus results in yellow or colorless colonies. For the flower petals, I used C. freundii, a bacterium which ferments lactose and therefore turns the colonies and agar pink in the areas it is grown.
On the EMB plate, I used three different Gram-negative bacteria (C. freundii, N. flava, and P. Mirabilis) to form a smiling emoticon. Even though I made my choices of bacterium based on the colors they present with on TSA, I think this painting still turned out acceptable as it seems I picked two bacteria which ferment lactose to different degrees as well as one that does not ferment lactose. This is evidenced in the different colors the three bacteria present with on this agar type (black and red for the fermenters and pink for the non-fermenter).
My name is Kjersten Williams, and I am currently a senior at UAF. I graduated with my Associate’s in Dental Hygiene in Spring 2015, and have since then been working part-time as a dental hygienist while also taking a couple of classes each semester to complete my Bachelor’s of Science in Biochemistry/Molecular Biology.
I will continue working in dental hygiene for quite some time with the option to pursue dental school or a career in dental research/lab work in the future. I will be working with a mentor on a research project this semester involving measuring the stable carbon isotope ratios in breath, and am super excited to begin! In my free time, I like reading, cross-stitching, horseback riding, and spending time with my family (including my chinchilla, my horse, and our Schnoodle!).