NJCU - Works of Cell Biology

Saturday, October 29, 2005

What my cells did this semester.

My cells were very privileged this Fall 2005 semester. A gifted cohort of University students has worked with me during this period towards greater understanding of the biology of the cell. I am proud of their journey and inspired by their progress. Their reflections of knowledge and examples of excellence are shared with you here.

-CJA

18 Comments:

At December 21, 2005 6:14 AM, Anonymous Anonymous said...

In the beginning of this semester synaptic signaling between my neurons was in slow motion, almost as if the neurotransmitters were diffusing through molasses. My brain cells took some time to get accustomed to the grind of coming to class after work every day. I worked long hours at Newark Liberty International airport as a security officer. After 9-11 you can imagine what that was like! After an eight hour shift my leg cells were weak from standing; my brain cells, heavy and dull with the stress of having to deal with the politics of the job. When I found out that my grades were slipping again this semester I decided that drastic times called for drastic measures. I eliminated some of the bad habits that my cells had welcomed into my life and recommitted them to doing better. Right now I have them working ferociously with each other so that I can earn a B+ in Cell Biology and a C in Immunology. My brain and body cells tell me that it is time for me to graduate. It is now or never. What else did my cells do this semester? They learned a lot. I, through them learned that cells are real not just part of a theory that someone thought of.
Mine are human and they are alive. In the best case scenario all they want to do is to serve me the organism. Some divide often, their proliferation becoming something that is useful to me and to the world. I realized that at the core of everything living is the biology of the cell; it is no wonder that cellular phenomenon are studied so much by scientists. Cells form a vital and intricate part of the human existence and of any existence. My cells have been through a lot this semester as well as all of my life. I believe that everything my cells have been through has become an integral part of me in some way. The construction of my knowledge and my life experiences is surely laid down in pathways of connection between neurons. But, are they part of my DNA too in ways that science can only begin to imagine? Will the DNA of my cells tell the story of who I was through transcription to the next generation? I can only wonder and appreciate in all of this, my part as a student of Biology.

With great respect,
Rachael Adewumi, New Jersey City University

 
At December 22, 2005 10:32 AM, Anonymous Anonymous said...

What my cells did this semester

Reflecting on this past semester I find that my journey of knowledge took numerous unexpected turns, yet proved to be most didactic.

This cell biology course went above and beyond all my expectations, and I am forever in debt to Dr. Arrigo for opening my eyes to the enchanting world of the cell.

As an example of this long journey I have endured, I have chosen to include a research paper listed below, which tore me apart as I was writing it, but helped me rebuild my knowledge and gain greater understanding, not only for this specific topic, but for cell biology in general.

Thank you Dr. Arrigo for believing in all of us, and providing guidance and support on this journey of the cell.

Sincerely yours,
Kathrine Bendtsen

Characterization of an activity from Solanum tuberosum cell extract

Kathrine Bendtsen, Department of Biology, New Jersey City University

Abstract:
Cell extracts are important reservoirs of information. The activities they hold can tell much about the biology of the living cell. Solanum tuberosum has been found to catalytically generate benzoquinone in response to tissue damage. This particular catalytic reaction is created by catechol oxidase. Biological catalysts are important to life as they decrease the amount of energy required to perform a certain function. By reducing the activation energy required, an enzyme affects the rate at which a reaction occurs. A catalyzed reaction can occur thousands of times faster than reaction that proceeds without the presence of an enzyme. Many factors have been known to alter the efficiency of enzymes, and I will attempt to describe the effects of same, through an experiment with Solanum tuberosum cell extract.

Methods and Materials:
A standard protocol for assessing activity under varying conditions was kindly supplied by Dr. Cindy Jo Arrigo, New Jersey City University. A spec 20 spectrophotometer was utilized for absorbance readings. A serial dilution methodology was utilized with 10-fold serial dilutions formed from a stock solution of Solanum tuberosum cell extract as part the investigation to assess toxicity of benzoquinone in a bacterial system. Solanum tuberosum tubers were locally supplied. All reagents were of molecular biology grade. Staphococcus aureus cultures were the kind gift of Dr. Howard Singer, New Jersey City University.

Results:
Activity and a putative catechol oxidase inhibitor.
A spectrophotometrically measurable product (Abs540) evolved in the presence of Solanum tuberosum cell extract and catechol. Without the presence of catechol there was no observation of a catalytic reaction. As 1% hydroquinone was introduced in the solution of cell extract and catechol, there was a decreased activity recorded. The results suggest that the similar chemical structure of catechol and hydroquinone negatively affected the reaction, due to hydroquinone binding to the same active site as catechol. As 2-fold decrease in activity compared to control (catechol alone) was observed in activity when hydroquinone, a putative inhibitor, was present.

Activity as a function of temperature.
Effects of temperature on enzyme activity showed two peaks activity, one at 27.5 degrees Celsius and the other at 63 degrees Celsius. This was the first indication that two or more enzymes may be responsible for the observed activity. Notably, activity was nearly depleted after incubation at 100 degrees Celsius suggesting that the activity observed resulted from an enzyme.

Activity as a function of pH.
Results from samples that were tested for an optimal pH showed two peaks of activity, one evident at pH2 and another spanning the pH 6-8 range. This suggests two activities that could signify that the two may be contained either in a single protein, or in two separate proteins. This could be indicative of two groups that are influenced by pH or two enzymes each with groups that are affected by pH.

Metal independent activity.
In order to clarify whether the activity observed resulted from catechol oxidase, its copper binding requirements (Gerdemann, Eicken and Krebs, 2001) were exploited. PTU crystals and a high molar EDTA solution were used to remove metal ions from solutions and strip any protein enzymes of their bound metal cofactors.

Results show that the presence of PTU crystals and EDTA in the activity bioassay increase activity levels. This allowed catechol oxidase to be ruled out as the primary enzyme responsible for the observed activity.

Assessment of toxicity of cell extract on Staphococcus aureus cells.
A serial dilution strategy was used to assess the toxicity of Solanum tuberosum cell extract in a bacterial model system. Since the product of the catechol oxidase reaction produces benzoquinone a molecule suspected to exhibit microbiostatic properties (Hassan, Maslat, Abussaud, Ahmed and AlKofani, 1973) the presence of this enzyme and its product in the cell extract could be assayed indirectly by asking whether toxicity was concentration dependent. Results indicate that the higher the concentrations of cell extract the lower the growth of Staphococcus aureus.


Discussion:

The effects of an enzyme and other factors such as substrate specificity, temperature, pH, and cofactor necessity were reflected in our results as expected.

The results that the enzyme catechol caused a catalytic reaction, and when hydroquinone was introduced the activity was sharply declined. This is due to the chemical composition of the two substances, and their substrate-specificity. Both substances were able to bind at the active site, hence a reduced activity was found in the presence of both catechol and hydroquinone.

The environmental temperature of the given life form also plays an important role in the activity of the enzyme. Our results exemplifies that the enzyme increases activity at normal warm weather temperature, and again peaks at a much higher temperature. It is, however, not present at 0 degrees Celsius, or from 38.5 - 50.5 degrees Celsius.

Most enzymes function best at a neutral pH, which is around pH 7. Our experiments showed exactly this, with the greatest activity found at pH 7. Before pH 4 and after pH 8 were a sharp decline in activity. As the Solanum tuberosum cell extract operates in a neutral pH environment, the enzymes it utilizes also function best at this pH level. The optimal pH is determined to be pH 7.

Certain cofactors have found to be necessary in order for an enzymatic reaction to occur. PTU and EDTA are metal chelating compounds, which bind to copper by removing it from the available solution. In metal depleted conditions brought about by PTU the observed activity was high.
Activity loss with EDTA was less pronounced. These findings rule out catechol oxidase as the primary determinant of the observed activity since the enzyme is known to require copper coordination at its active site (Gerdemann, Eicken and Krebs, 2001)

Staphococcus aureus bacteria growth was negatively affected by Solanum tuberosum cell extracts. This finding is consistent with literature suggesting that benzoquinone, a substance with a characteristic absorbance at 540nm, has bacteristatic properties.

This study confirms the work of others supporting the notion that enzyme structures are sensitive and allow activity only under certain circumstances. Our results indicate that the activity characterized was sensitive to temperature, pH, substrate-specificity and cofactors in particular. Analysis of the data, as assessed from the values obtained, rules towards the presence of the activity being enzymatic and suggest that two or more enzymes may be responsible.

Our data also suggested that catechol oxidase is not the primary enzyme responsible for activity, which suggests further study is required to determine what the primary enzyme responsible for activity in Solanum tuberosum tubers is.


References:

Gerdemann C., Eicken C., and Krebs B., The Crystal Structure of Catechol Oxidase: New Insight into the Function of Type-3 Copper Proteins, in Accounts of Chemical Research, (2002) Volume 35, Issue 3, pp 183-191.

Hassan M. A., Maslat A. O., Abussaud M., Ahmed I. C. AlKofahi A. S., Metabolites accumulating in potato tubers folloing infection and stress, in Teratology, (1973) Volume 8, Issue 3/December, pp 333-338.

Campbell, Neil A. and Reese, Jane B., (2002) Biology 6th edition

 
At December 23, 2005 4:37 PM, Anonymous Anonymous said...

During the fall 2005 semester I exhibited excellence in Dr. Arrigo’s Cell Biology class as I made a transition from MLA writing format to APA, the format used in publishing scientific literature. Expression of your accomplishments through the articulation of your words and thoughts is how the scientific world will accept your achievements as proper or disregard them as unaccomplished. Dr. Arrigo has instilled in me the power through her education to allow me to attempt to excel in excellence in the laboratory. Below is a review paper that I completed during this semester that illustates my knowledge of how to read, extract, and articulate properly from a scientific published work, Stomatal conductance does not correlate with photosynthetic capacity in transgenic tobacco with reduced amounts of Rubisco.

Susan Jankovic, Department of Biology, New Jersey City University

Von Caemmerer, et al’s Stomatal conductance does not correlate with photosynthetic capacity in transgenic tobacco with reduced amounts of Rubisco illustrates the idea that tobacco plants’ guard cells do not receive their energy directly from their own photosynthetic activity. The experimental research has found that guard cells are not reliant on their own photosynthesis or the photosynthetic electron transport for the maintenance of stomatal conductance. This stomatal conductance of guard cells is the regulation of the opening and closing of the stomata to regulate gas exchange and water regulation in leaves of plants. Stomatal conductance of most leaves responds to changes in CO2 concentration. Stomatas open when CO2 concentrations are lowered and close when CO2 concentrations are increased (Mansfield et al., 1990; Assman, 1999; Cousson, 2000).
Von Caemmerer, et al (2003) used intact tobacco leaves in their experiment to determine if there was a correlation between the actions of guard cells and how they receive their own energy to perform this action. The intact leaves were used to compare the total yield of photosynthesis II’s electron transport in the chloroplasts of guard cells with that in the underlying mesophyll cells. Trying to determine this would indicate where the guard cells receive their energy from to perform this important function to the existence of terrestrial plants. The control portion of the experiment was the wild-type of the intact tobacco leaves and the experimental group consisted of tobacco plants with reduced amounts of Rubisco, anti-Rubisco plants.
Von Caemmerer (2003) provided the results that the yield of photosynthesis II in both guard cells and underlying mesophyll cells was less in the anti-Rubisco plants than in wild-type plants. Their discovery of this information was also a bit irrelevant to the final outcome due to the fact that this difference in the Anti-Rubisco and wild-type plants’ photosynthetic capacity did not cause a discernible difference in the rate of stomatal opening. The rate of stomatal opening was not affected by the altered guard cell photosynthesis. Finally, Von Caemmerer, et al’s experiment concluded that stomatal conductance is not directly determined by the photosynthetic capacity of guard cells or the leaf mesophyll.

Assmann SM. 1999. The cellular basis of guard cell sensing of rising CO2. Plant, Cell and Environment 22, 629–637.

Cousson A. 2000. Analysis of the sensing and transducing processes implicated in the stomatal responses to carbon dioxide in Commelina communis L. Plant, Cell and Environment 23, 487–495.

Mansfield TA, Hetherington AM, Atkinson CJ. 1990. Some current aspects of stomatal physiology. Annual Review of Plant Physiology and Plant Molecular Biology 41, 55–77.

Von Caemmerer, Susanne. 2004. Stomatal conductance does not correlate with photosynthetic capacity in transgenic tobacco with reduced amounts of Rubisco. Journal of Experimental Botany Vol. 55, No. 400 pp.1157 – 1166.

 
At December 25, 2005 9:32 PM, Anonymous Anonymous said...

What my cell did this semester?
In the beginning of the semester my cell were doing the same thing as they did during the summer. They were replicating, diving, and communicating. However, my brain cells were 100% active during this semester. They had to memorized and understand the material given to me in each of my classes. For example, for my cell biology class I had to be familiar with the noncyclic electron flow during the light reaction generates ATP and NADPH, the detailed structure of an animal cell’s plasma membrane, the Calvin cycle, the stages of transcription for RNA and other important concepts. Nevertheless, my cell had to understand the material before trying to remember it. Our professor made us recited the noncyclic electron flow during class; I think this was a great idea since I was able to understand the information in my own words. I can’t remember things that I don’t understand; as a result, I can’t develop a clear and accurate memory from a fuzzy, weakly understood concept.
I was able to show knowledge in the labs assigned in class. I believe my cells were excited and active working with the pGLO transformation and purification. My lab partner and I had the best colonies. The colonies were spread evenly around the surface of the LB nutrient agar and they glowed a lot when exposed to ultraviolet light. In addition, I demonstrated knowledge in my lab reports showing of what I had learned in each of my labs. Moreover, there were many good things that I learned in this cell biology course; I express gratitude to Dr. Arrigo for showing us this new delightful world of the cell.
I have chosen to include a research paper as part of what my cell did during this semester because it’s showing one of the many good things I learned during this semester.

~Responses of primary and secondary metabolism to sugar accumulation revealed by microarray expression analysis of the Arabidopsis mutant, pho3~

Arabidopsis Thailiana is a plant used by plant science researchers to examine or study developmental processes. Therefore, this plant is a good model organism that helps science researchers in their study of genes. A recent study used an Arabidopsis mutant to examine the level of gene expression through a method called microarray analysis. The mutant organism showed high levels of sugar accumulation (glucose, fructose and sucrose) and carbohydrates. Moreover, very large increase was observed in the expression of transcription factors and enzymes involved in anthocyanin biosynthesis (OV Zakhleniuk and JC Lloyd). Anthocyanin is the principal pigment in flowers, conferring intense red-to-blue colors on petal and helping to attract pollinators. Its biosynthesis involves glycosylation steps that are important for the stability of the pigment and for its aqueous solubility in vacuoles (Nogi-Yamaguchi, Aomori). The red color in leaves becomes redder when additional sugar is stored. These factors were used to investigate how genes in the primary and secondary metabolism responded to the high levels of sugars. The primary metabolism is vital for the reason that it controls all pathways and products that are indispensable for the cell itself. Secondary metabolism is not important for the survival of the cell; however, it’s important for plants. They lead to products like flower colors, aroma and taste, reinforce elements, toxic factors, etc.
Sugars are important to regulate the plant life. As a result, a possible role for the direct sugar regulation of genes encoding components of sugar signaling pathways has recently emerged (OV Zakhleniuk and JC Lloyd). Trehalose-6-phosphate is also being related to the regulation of sugar metabolism, especially in source/sink regulation and signaling (Eastmond et al., 2003). A sugar source is a plant organ in which sugar is being produced by either photosynthesis or the breakdown of starch. In the other hand, sugar sink is an organ that is a net consumer or storer of sugar (Reece B. Jane and Campbell A. Neil).Therefore, the source/sink is important for the regulation in the expression of photosynthetic genes.
There is a lack of knowledge regarding the function of most protein; consequently, it limits the understanding and the changes in the transcript levels of the plant. However, this experiment showed a new connection in the regulation of primary and secondary metabolism.

References:
Lloyd C. Julie, Zakhleniuk V. Oksana. “Responses of primary and secondary metabolism to sugar accumulation revealed by microarray expression analysis of the Arabidopsis mutan, pho3.” Oxford journals

Eastmond PJ, Li Y, Graham I.A. (2003). Is trehalose-6-phosphate a regulator of sugar metabolism in plants? Journal of Experimental Botany 54, 533–537

Jun O, Yoshiaki K, Yoshio I, Hidehito T., Masahiko S,.(2005). “Plant biochemistry: Anthocyanin biosynthesis.” Nature weekly journal of science. 435, 757-758

Reece B. Jane and Campbell A. Neil. Biology. San Francisco. 2002

Sincerely yours,
Ines P. Bajaña

 
At December 25, 2005 11:35 PM, Anonymous Anonymous said...

The Fall 2005 semester was a difficult and grueling process. My cells replicated, divided and were driven to do massive activity. I enjoyed every moment I spent in cell biology class. The teaching methods that Dr. Arrigo had were excellent. She taught the material in class in a different manner that made it capable for me and others to understand. One lecture that I kept in mind is when Dr. Arrigo made us interact and comprehend the process of photosynthesis I and II. I think that these types of activities help everyone show knowledge and give input. I also found that having a lab notebook is very helpful during lab exams and knowing the procedures done in labs.
I accomplished a lot more during lab and laboratory reports. I was able to learn and acquire the knowledge to demonstrate lab techniques. The laboratories that were assigned in class were precise and exciting. My cells were overwhelmed with work at times during labs. One lab that my partner and I felt very proud of is the pGLO transformation and purification. My lab partner and I obtained the best colonies. The colonies were spread evenly on the LB nutrient agar and when exposed to ultraviolet light they glowed brightly. This laboratory was also especially frustrating when my lab partners and I were in the final phase of purifying the green fluorescent protein. A laboratory report that I demonstrated my skill in writing a short communication and knowledge was the photosynthesis lab.
I’m grateful that I was taught by such a prestigious professor. Dr. Arrigo helped me realize how much hard work it takes to get to the top and to achieve. I now know that each step that is taken in life is a long process but is worth all the work. I wouldn’t regret any moment and long hours spent doing labs and studying.

Susan Bellocq, Department of Biology, New Jersey City University

 
At December 26, 2005 4:11 PM, Anonymous Anonymous said...

It is immpossible to memorize so many details and facts about science and keep them with you forever. My cells learned that understanding the concepts behind them is alot easier. In view of science in general it seems that much of it is common sense. In
todays materialistic world most all things are made with a structure to support its function. When this is untrue it could certainly fall apart and when it does something better will evolve. This is also demontrated in the microscopic world of cells -structure seems to determine function. When some portion of the structure is amiss it will not
function properly unless something had occured or was formed to compensate for it. Right down to our genes it seems to ring truth.

My cells have also learned how to research and sort out specific scientific information from an abundance of quality scientific literature (not as easy as going into google and typing in key words). This is one of the more important things I have learned because it will be useful for the rest of my education and after in trying to keep up with such a
scientifically dynamic world.

Mathie Tarabocchia, Department of Biology, New Jersey City University

 
At December 26, 2005 4:16 PM, Anonymous Anonymous said...

As my journey through Cell Biology took its course, I was able to gain knowledge and a true understanding of cells as individuals. I grew also to appreciate how cells cooperate and hold important responsibilities and functions as members of multicellular tissues and organisms. An example of one of my journeys this semester that ended in a discovery of my excellence is below. Here I demonstrated an application of knowledge to a question concerning an activity elicited from Solanum tuberosum cell extracts.

Short Communication: Characterization of an Activity from Extracts of Solunum tuberosum cells
Yajaira Sanchez
Biology Department, New Jersey City University, Jersey City, United States

Many plants enzymatically generate benzoquinone in response to tissue damage, but in its absence, benzoquinone is not formed because different intracellular compartments sequester reaction components. Catechol oxidase is an enzyme that destroys toxins and makes melanin sun screen. When in the presence of oxygen, catechol oxidase catalyzes the removal of electrons and hydrogens from catechol, a phenolic compound found in plant cells. The hydrogens combine with oxygen, forming water (Gerdemann, Eicken, and Krebs, 2002). Catechol is converted to benzoquinone, a pigment product. The pigment products are responsible for the darkening of fruits and vegetables, such as apples and potatoes, after exposure to air (Duke et al, 1983). Benzoquinone has been suggested to have antimicrobial properties. In Solanum tuberosum catechol oxidase works as a catalyst for the oxoreductase reaction that gives rise to benzoquinone. We expected to find a catechol oxidase-like activity in Solanum tuberosum cellular extracts and sought to characterize the activity using standard enzymatic perimeters. Activity was assessed by evolution of a product that absorbed at 540nm. Absorbance readings at 540nm wavelength were recorded and analyzed from independent observations: pH, assessment of metal binding requirements and activity in the presence of a putative inhibitor was explored. RESULTS: A pH profile (Figure 1) showed a peak of activity between pH 8-10. A view of the toxicity of the activity in Staph aureus extracts (Table 1) shows that at high concentrations of cell extract bacterial growth was inhibited. These data taken together with the literature suggest that catechol oxidase was the enzyme responsible for the activity.
Figure 1

Figure 1: Cell extracts were incubated in phosphate buffer of the indicated pH and activity was assessed by spectrophotometric reading.

Table 1
Extracts from Solunum tuberosum cells show a dose dependent bacteria static property.
Concentration of Cell Extract
Concentration of Cell Extract Turbidity
0.1X 0
0.01X +
0.001X ++
0.0001X +++

REFERENCES

Gerdemann, C., Eiken, C., and Krebs, B (2002) The Crystal Structure of Catechol Oxidase: New Insight into the Function of Type-3 Copper Proteins, Acc. Chem. Res., 35 (3), 183-191.


Mohamed A. Hassan, Metabolites Accumalating in Potato Tubers Following Infection and Stress, Terotology. 1973, 8 (3), 333-8.

Submitted by Yajaira Sanchez, Biology Department, New Jersey City University, Jersey City, United States

 
At December 27, 2005 8:54 AM, Anonymous Anonymous said...

Cells are the structural units of all living things. Every second, these tiny microscopic entities endure challenges that allow them to function properly. It is safe to say that we probably do not really put much thought into what is happening inside of our bodies but as I learned through this course, there is a lot going on inside of cells and all of us. This semester, my cells met many of the challenges in a rigorous 16-week course in Cell Biology. Although my cells already work 24/7, I think they had to work even overtime during this course. Catabolism of food molecules and the coupled synthesis of ATP provided the energy for all of the cellular work I performed during this period. In addition to organelle functions, my cells also needed to communicate with their local environment and with me, the organism. Much communication was afforded by communication through receptors including cell surface receptors, channel-linked receptors, G-protein linked receptors etc. Some of my cells also underwent cellular division and more cells were created to function in my system. All of this was life’s work, an ongoing process that thankfully has not ended.

Life is work, and in essence I was shown this during the whole semester. Our cells do not have
vacations; we can not afford to give them. Appreciating our cells and the science that discovers their mysteries goes without question and that is something that was learned throughout this course.

Abilash Jilla; Biology Department; New Jersey City University

 
At December 27, 2005 11:07 AM, Anonymous Anonymous said...

What my cells did this semester?

This semester was by far the toughest one yet. It was very hectic for me not because I have taken too many courses but because they all were higher level courses. However, I always had my closest friends named “cells” who coped with me throughout one of my toughest time in understanding some of cell biology concepts like: the structure and function of the organelles, cellular respiration involving Glycolysis, the Krebs cycle, and electron transport, the Calvin cycle, Photosynthesis, Cell communication (from reception, transduction, and response in cell signaling), Metabolism, ATP synthesis, Mendel’s gene discovery, the connection between genes and proteins, DNA, RNA and many other important concepts. As everybody knows, every function in biology involves a process that occurs within cells or at the interface between cells. Therefore, we need to appreciate the structure and function of the different parts of the cell as well as the properties that define the plasma membrane that surrounds the cell. Now the concepts seem clear to me because I have read it in the text book, put it into my own words with the help of Dr. Arrigo, and performed it in my weekly labs. Lab reports were extremely difficult for me to write in the beginning because it had a very different writing style to it however, now I could proudly say that I can write fairly good scientific lab reports. Like I have mentioned above my cells has been dividing, replicating, communicating and it has been very active this whole semester because of all the memorization and the knowledge I received in my classes, especially in cell biology. So, I forever am thankful to Dr. Arrigo, for wanting the best for all her students and wanting to help as much as she can in making us understand the concepts of cell biology and life itself.

-Payal Shah, Biology Department, New Jersey City University

 
At December 27, 2005 6:23 PM, Blogger LAdams said...

What My Cells did the Semester


This semester was very challenging but also rewarding. I was able to acquire scientific knowledge and demonstrate it in many aspects. I had the opportunity to perform serial dilutions and use pipeting techniques to determine solution concentrations. I also exhibit excellent microscopy skills which were acknowledge by my Professor and my colleagues. I was the first student in the NJCU 2005 Cell Biology courses to show excellence in making and then identifying HeLa cell splats. One of the most fascinating laboratory exercises that I performed concerned concepts related to gene engineering. I inserted a jelly fish gene into HB101 cells and transformed them forever. My work generated organisms that were ampicillan resistance and under the control of an arabinose regulated operon produced green fluorescent protein. Throughout the semester I was called upon to analyze my own work and that of others and I met that challenge. Additionally, I adapted to the idea of quality instead of quantity when writing scientifically. The skills and knowledge that I obtained were also demonstrated throughout written and oral examinations. In time I found myself utilizing scientific literature from a variety of sources and demonstrating knowledge through writing short communications, reflections, laboratory reports, and an independent research paper. Throughout different aspects, I acquired the ability to reflect excellence in written reflections and in data analysis. The skills and knowledge that I’ve gained will continue to be of value to me and an asset to society in any future endeavors that I will part take of.

Latasha Adams, A.S. New Jersey City University

 
At December 27, 2005 6:45 PM, Anonymous Anonymous said...

During this semester my cells were actively involved in the Cell Biology class, learning much about what they are all about; their structure and function. During the first week of class they were told about the work that was required of them and the various routes they could take to accomplish it. They were very excited to learn about the mechanisms that keep them going. However they were a bit concerned about their writing skills. Being that communication is one of their main jobs, they began to talk and said to each other,"It is ok, we will be alright". They took the challenge, and turns out that they found themselves doing great things in this class. Many times, they had accumulated enough information to tell a story about their own metabolism and their physiology, other times they simulated the parts of some of their main componets such as mitochondria which carries out one of their main function, cellular respiration. Other times they acted as hexokinase phosphosphorylating a molecule of glucose during the process of glycolysis and they had much fun when they were part of the electron transport chain helping to create that proton gradient that will keep them a current supply of energy.

During the labs, they fell like real scientists. They took a look at some wonderful chromosomes from the human HeLa cell line. They grew bacteria and genetically transformed them using a plasmid DNA that provided them with Green Flourescent Protein. They were later able to recover both the GFP and the pGlo plasmid DNA in two different processes, protein chromatography and agarose gel electrophoresis.

Many, were the wonderful experiences in this class from which my cells can proudly say they gained invaluable skills and knowledge. My cells are greatly thankful to Dr. Arrigo for providing such wonderful guide and support throughout the semester and for the honest concern she puts into her student's learning.

It also turned out that my writing skills were not much to be concerned about. Take a look at the short communication below and judge for yourselves.


Short Communication

The Transformation of an Organism: Griffith’s work revisited

Ina R. Travieso, Department of Biology, New Jersey City University


This investigation marks the completion of a line of experiments that modeled after Griffith’s work of 1928, The Significance of Pneumococcal Types. By combining heat-killed cells from pathogenic S strain bacteria with living non-pathogenic R bacteria, Griffith showed how the non-pathogenic strain had acquired the pathogenic trait that was evident in a retrieved sample of the organism. This discovery of bacterial transformation laid the ground for intensive work in search of the transforming factor, which consequently lead to the discovery of DNA as the genetic material.

During the first of four successive experiments, bacteria was transformed applying a standard heat-shock protocol by which the model organism, E. coli was enabled to bind the naked DNA from its cultured medium. Bio-Rad’s pGLO plasmid was utilized for this procedure. Plasmids are self-replicating circles of DNA used as the vehicle for transferring recombinant DNA into a host cell. The pGlo plasmid contained an ORI and genes that encode for GFP, ampicillin resistance and AraC. The transformed cells were identified upon their growth on agar plates containing both ampicillin and arabinose sugar, the latter acting as on-off switches for the expression of the Green Fluorescent Protein. What was truly relevant about this process was the visualization of this genetic transformation not altering the phenotypic character of the organisms not exposed to the plasmid as well as those that were exposed but not provided with arabinose nutrient. This observation supports Griffith’s findings when he encountered that neither, the living non-pathogenic or non-living pathogenic bacteria caused a disease when acting alone (Griffith, 1928)

The experiment was followed by a recovery of the GFP protein in the transformed cells by a standard cell lysis procedure and protein chromatography. It was impressive to observe that as expected, the hybrids of the original transformed bacteria had inherited the traits that were formerly introduced to their parental counterparts. As well, this observation suggested that they were able to replicate the plasmid allowing the foreign genes to be transcribed and translated into the proteins that enable them to exhibit their inherited characters.

Subsequently, laboratory bio-technicians subjected the transformed cells to further culture and a plasmid DNA extraction protocol. This process of isolation and other methods of DNA purification use the same basic principles in making use of DNA’s chemical properties such as the molecule’s solubility and its negatively charged condition. Completing the final phase of the investigation, plasmid preparation samples were analyzed by 0.8% Agarose gel electrophoresis. Migratory pattern of any ethidium bromide stained bands were compared to the migratory pattern of pGLO plasmid from the original transformation experiment.
RESULTS: The visualized results provided substantial evidence that revealed that pGlo plasmid had been passed on from the first organisms to the lasts as suggested by the specific band pattern that corresponded with that of pGlo. This experiment provides strong reinforcement on the concept of Central Dogma, as organisms can be studied in terms of their genes and the messages they translate.


REFERENCES:

Griffith, F. 1928. The Significance of Pneumococcal Types. Journal of Hygiene.


-Ina R. Travieso, New Jersey City University

 
At December 27, 2005 7:46 PM, Blogger Melissa said...

My cells had a very busy semester. They spent the last three months trying to make sense of their history, structure, function and purpose in this amazing universe. This was not an esay task, however in the end, they realized that the reward of knowledge tasted must sweeter than the bitterness of hard work.

It came as a shock to them when they learned about their origin. All this fuss over a thin slice of oak cork that an English scientist named Robert Hooke examined around 1665. They were named after a monks room because Robert Hooke thought thats what they resembled. Somebody should have told that guy to get a clue. Anyway, he made them really popular amongst the scientific community and thus began lifetimes worth of research.

My cells were even more surprised when they learned about how busy they really are. They practically never get a break. Theres 200 different types of them and it's imperitive that they all work together at synchronized times of day and night to make molecules that my body needs to grow, multipy and survive. They all have their own job and responsibilities and if one fails, it could cause the whole system to shut down.

Believe it or not, but two-thirds of a cell is made of water. Sounds simple considering their workload huh? The rest is a mixture of molecules-mainly proteins, lipids and carbohydrates. Using thousands of different chemical reactions, they turn the raw materials in the food I eat into the molecules my body needs for survival. The carbohydrates I eat provide them with energy. The simplest are sugars, like glucose, fructose, sucrose and lactose. Complex carbohydrates, like starch, are made up of lots of sugar molecules joined together. The antigens on the surface of all cells are made from carbohydrates that are joined to proteins. These molecules allow my cells to recognise each other and keep the different parts of my body working together. The different types of lipids in my body include fats, oils, waxes and steroids. My body uses fats as a supply and store of energy. The steroids in my body include some hormones. Other lipids make up the outer layer of all my cells, and the fatty sheaths that insulate nerve fibres. Proteins are my cell's "workers". I have thousands and thousands of different proteins in my body. Some serve as building blocks. Other kinds of proteins carry oxygen around my body, fight infections and detect the light entering your eyes. An important group of proteins called enzymes, controls the rate of the chemical reactions in my body that make all the other molecules you need. Without enzymes, these reactions would take place too slowly to keep me alive. Some enzymes break down large molecules into smaller ones. Others, like the enzymes that make DNA, use small molecules to build up large complex ones. Enzymes also help my cells to communicate with each other, keeping cell growth, life and death under control. Not so simple anymore huh?

My cells learned about all the different compartments within themselves that help carry out the process of life. For example, all of the Advil and Aleve that I took this semester to ease the headaches caused by Cell Biology were sent to the smooth endoplasmic reticulum for detoxification. All of the characteristics that make up the "physical" me come from the nucleus. DNA is what makes me unique and unlike and other living organism in the world. Each of my cells contain all the genetic instructions stored as DNA in the nucleus. Each very long DNA molecule is tightly wound and packaged as a chromosome. Each DNA molecule that forms a chromosome can be viewed as a set of shorter DNA sequences. These are the units of DNA function, called genes, each of which guides the production of me. A chromosome contains hundreds of genes, which are composed of DNA. There are many more different compartments, each with its own structure and function which allow me to be alive and healthy.

My cells were really scared when it came time to learn about cancer. Listening to how they can go wrong was really hard for them. My body is made up of 100 million billion cells and cancer can start when just one of them begins to grow and multiply too much. The result of this is a growth called a tumour. Benign tumours are localised growths - they only cause problems if they put pressure on nearby tissues, such as the brain. Much more serious are malignant tumours, which invade the surrounding body tissues. Some malignant tumours can also spread throughout the body via the bloodstream. It was even scarier when they learned that cancer is genetic. However, they secretly promised me that they would do everything in their power to prevent this from happeneing to my body.

My cells also did a lot of research this semester on embryonic stem cells-they were amazed at how much progress has been made in the scientific community since Hooke first discovered them. They were also pleased to know that they can assist in proving cures for many diseases that invade the human body.

My brain cells are getting tired now so i'm going to give them a break before they stop working properly and I start typing something that could end up costing me points on my final grade. Summing up everything my cells learned this semester in one essay is nearly immpossible. However, I'm positive that eveyrthing they learned has been carefully stored in a part of my brain labeled "Dr. Arrigo - Cell Biology." Anytime i'm feeling lost, I'll refer to it and "MAKE IT HAPPEN."

Melissa Khiry, New Jersey City University

 
At December 27, 2005 9:07 PM, Anonymous Anonymous said...

Well, the journey through Cell Biology was anything but boring. It was an experience that has taught me some very valuable concepts that I know will come in handy as i continue down the path to a B.S. in Biology.
My brain cells made quite a number of connections and renewed a lot of those old connections as well. I learned to use micropippettes, that cost $500 each, to master the art of srieal dilution. This skill will undoubtedly help my cells in the future to push all of me foward in my chemistry classes and also in my career field. I, I mean my cells, became aquainted with the procedure for unsing a microscope. I must confess that I was never taught the proper protocol for handling and using a microscope.
My cells also had some fun playing with the extracts of other cells and testing the conditions they like.
This I must say was a lot of fun but fails in comparison to what we did to the E. Coli cels we had. It was great for my cells to learn how easy it was to change cells and make them do things that were totally unnatural to them. I was amazed and scared at that fact all at the same time. If this was to fall inthe the possession of the wrong cells it would not be good.
That was the only fear my cells had but other that that we all enjoyed the experience.
I don't know but I think that my cells had fun making the agarose gels and getting the characteristic bands that showed the presence of certain desired traits.
Looking at protein profiles educated my cells about the key components of them and it also showed that we are not really that different.
Now I fell that my cells have expressed all that they wanted to and it is now time to end our little monologue on Biology and also to mention that me cells also enjoyed being exempted from the final exam, it was something we greatly appreciated. We finally get to see some of the fruits of our labour and it was sweet.
Now it is finally time for we cells to rest and hand in the final review paper. We were a bit stressed and did not hand it in on time but we did try. We are sorry for this.
Yours Respectfully,
Andray Tandacharry
Former Cell Biology Student
Dr. Arrigo, NJCU

 
At December 28, 2005 6:04 AM, Anonymous Anonymous said...

On a regular day during the fall semester 2005, my cells underwent varies types of action. Cells are
the basic unit of life, and are the smallest structure in biology that have all the properties of living things. All cells have at least three things in common, a cell membrane, a cytoplasm, and DNA.

The cell membrane in my body regulated the movement of water, nutrients and wastes into and out of my cells. The organelles inside of my cells helped carry out the day-to-day operations of all my cells. Ribosomes are highly important to my cells because they participate in protein synthesis.
Transcription and translation, two phases of protein synthesis occurred in my cells during the past semester. The transcription phase of protein synthesis takes places in my cell nucleus. After this step is complete, the mRNA leaves the nucleus and travels to my cell's ribosomes, where translation occurs.

My cells have undergone cellular respiration, cellular reproduction and or cellular division. Cellular
respiration is the process of oxidizing food molecules, like glucose, to carbon dioxide and water. The energy released is trapped in the form of ATP for use by all the energy-consuming activities of the cell. Cellular respiration occurs by two mechanisms, glycolysis, and the compete oxidation of pyruvic acid.
Glycolysis is the breakdown of glucose to pyruvic acid. My cells have gone through cellular
reproduction which reproduces copies of preexisting cells. In cellular reproduction the cell grows for a while and then giving the proper stimulation divides to give rise to two cells. While most of the things in the cell can be roughly divided between the two daughter cells, the genetic information that has the
instructions for making everything in the cell must be divided up very precisely, which occurs through Mitosis. The genetic information is stored on chromosomes which, in eukaryotes (animals/humans), are kept in an organelle called the nucleus.

My cells this semester were supported by the extracellular matrix (ECM) that is embedded consisting of protein and polysaccharides. As well as being supported, my cells have communicated to one another through signaling with nearby cells by secreting local regulators. My cells communicated with each other this semester with the use of hormones and through direct contact. There are three stages in which my cells have sent signals which are reception, transduction and response.

The cells in my body were regulated through various systems. Cyclin and cyclin dependent kinases (Cdk) were a main component in regulation of the cells. Growth factors also helped with the regulation of my cells.

In conclusion, my cells have gone through a lot this semester and will continue to go through all these processes to keep me alive.

Damaris Escarment; Biology Department; New Jersey City University

 
At December 28, 2005 8:33 AM, Anonymous Anonymous said...

I see here an illustration of the power of intelligence and reason. The challenge of Dr. Arrigo and the intelligent comments of students are remarkably concise and well stated. All of your hard work is obvious and will surely be rewarded and honored.

It is so fantastic to see the transfer of eons of knowledge to the next generation. This is the very greatest feature of human existence. Thousands of years of knowledge are passed on in a few decades. Then, from this grand base it can be explosively reused, branched out and blossom to new understandings.

Education is a wonderful and tricky thing. Tricky, because the knowledge torch must be passed on in all its full glory, completely factual, untethered, unblemished, and unbiased. This knowledge then must be understood, examined,
accepted, used and grown in a meaningful way. This is very demanding and rewarding work. Whether the student's final goal is to simply "fill in the blank", or be part of the endless quest for answers; this is a noble, worthwhile struggle. The reward is experiencing this most remarkable tradition of knowledge transfer.

Nurture this most precious gift of understanding and develop your own unique "new" knowledge. Your enthusiasm, passion, and industry show through in your astute insight, and well founded remarks.

My congratulation on an extraordinary job, done well.

Robert Martin, Elkhart Kansas, USA

 
At December 29, 2005 5:31 AM, Anonymous Anonymous said...

Agha Khan, Department of Biology, New Jersey City University

What My Cells This Semester

This semester was an overwhelming experience. New ideas, innovative style of thinking, a superior grasp of the subject matter, and many new long lasting friendships. Each component was articulately embedded into our everyday lives. Our strengths were made stronger, and our weaknesses were succumbed into these strengths.
Every single one of my cells was consistently put under pressure. Pressure to do better, to succeed, and to push the limits to improve myself. Heading into this semester, my cells did not know what to expect. The first day of class, I was excited during the orientation. Reading the guidelines for the classes, I could not wait to start the learning process. Knowing that after completing each class successfully would give exceptional control of subject matter, gave me goose bumps.
As time went on, my cells were headed in all different directions. From Calculus II to Biology; from numbers and functions to detail cellular regulatory mechanisms. The ability to demonstrate quantitative reasoning and graphing ability as well as writing and interpreting literature were but some the objectives completed. During exams and tests were the times my cells were working the hardest. Being the smallest living structural unit of an organism, it gets hard trying to input too much information into them, however, in my opinion, I believe I managed. This semester exemplified and took to another level the basics that we have been taught since the beginning, english, math, and science. Although the names have changed, the main elements are still evident. Overall, I believe my cells were put thorough a lot. They are now at a level which they have never been at before. The amount of information learned will last and be passed on of many times to come.

 
At January 02, 2006 7:11 AM, Anonymous Anonymous said...

I have read most of the posts on "What My Cells Did this Semester", and as a cell biologist I am very impressed. I am most impressed with the imagnination and the breadth of experience of your cells, and your ability to be so in touch with their activities.
I think that many current working scientists spend a lot of time wondering where the next generation of scientists will come from and what they will be like. I am gratified to see such dedication and professionalism, and thank you for this glimpse into the future. I look forward to seeing these students continue to progress and hope that one day I will be collaborating with them and helping to solve some of the mysteries of the cell by their sides.

With great hope and best wishes,
Keith Micoli, Ph.D.
Research Associate
Department of Pathology
University of Alabama at Birmingam

 
At January 16, 2006 11:48 AM, Anonymous Carol S. Newlon said...

I have read through most of the things posted on 'What my cells did this semester', and I am really impressed with the excellence and creativity shown by all of you. One theme that resonates with me is the notion that understanding rather than memorizing is the key to progress. It appears that you have had a rich experience in the Cell Biology course taught my former student, Dr. Cindy Arrigo. I'm sure that parts of what you have understood will enrich your lives, wherever you end up.

Carol Newlon, PhD
Professor and Chair
Department of Microbiology and Molecular Genetics
UMDNJ-New Jersey Medical School
Newark, NJ

 

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