The Inside Story – Receptor-Mediated Endocytosis in Drug Delivery: By Jacob Cortez

Whenever someone gets sick, they need some form of treatment. Treatment can be a natural remedy or, most likely, a drug. In the case of more serious illnesses such as cancer, the only treatment is medicine. Medicine has been used to treat illness for most of the modern age, and you are probably familiar with many drugs. Have you ever wondered how those drugs work?


Close but no cigar.

A lot of anti-cancer drugs rely on clathrin-dependent receptor-mediated endocytosis. Now, that might sound a little complicated, but I’m going to break it down for you. Clathrin is a kind of coating protein for vesicles, little balloon-like sacs that allow different substances to enter a cell. These vesicles are created from the cell’s membrane after the target substance’s ligand binds to a receptor. Once the receptor binds a ligand, a vesicle is created, and the substance enters the cell within the vesicle. This is called receptor-mediated endocytosis. Neat, right?


Two of these ligands are transferrin and riboflavin. Transferrin binds iron and is a good target for drug delivery. Because transferrin travels across the blood brain barrier to deliver iron to the brain, it can be used to ferry drugs through the blood brain barrier to treat diseases that target the brain. Riboflavin is another important ligand for drug delivery. Early data suggests that riboflavin could be beneficial in drugs targeting breast cancer. The carrier protein that binds riboflavin has been found in increased levels in cancerous breast tissue, so the drug would have an easier time finding the tumor.

Receptor-mediated endocytosis is essential to many cell functions. Because of its necessity, it is very useful for drug delivery. New drugs are being developed every year, and, soon, we may have a easy way to fight cancer.


Bareford, Lisa M and Peter W Swaan. “Endocytic mechanisms for targeted drug delivery” Advanced drug delivery reviews vol. 59,8 (2007): 748-58.





Bacillus subtilis and Tetrahymena thermophila: By Camille Hart

If you are like me, when you see the names of these two organisms you are more worried about pronouncing them right than worrying about how they interact with their microscopic worlds. However, these small organisms are quite significant to our world! Bacillus subtilis are small bacteria that exist in the gastrointestinal tracts of many organisms. Including you! To be able to live in such an extreme environment, these little bacteria have evolved a unique set of armor. They surround themselves with multiple extracellular layers, one of the outermost layers being known as the spore coat. This layer protects these little bacteria from another microscopic organism, Tetrahymena thermophila, which would otherwise eat them in a process known as phagocytosis.

Phagocytosis by bltshop


The spore coat that helps to protect this little bacteria is more beneficial than you might think. Not only does the coat deter the ciliary protozoans, Tetrahymena thermophila, but it can also act as a guard against lytic enzymes. If the bacteria were to come into contact with these enzymes, the cell wall beneath the coating would be degraded. However, with this coat in place even if the bacteria are ingested, they cannot be digested, ensuring that the bacteria are able to live on.

Image result for phagocytosis meme

So what is the moral of this story? Why should we care about these little bacteria and their unique sets of armor? Well, while it has not been proven that the spore coat can actually protect the bacteria from being eaten, it has been shown that these coats can protect the bacteria from harmful lytic enzymes. If this spore coat was able to be replicated and put into applicable use in protecting our own cells, imagine the possibilities!


Klobutcher, L. A., Ragkousi, K., & Setlow, P. (2006). The Bacillus subtilis spore coat provides “eat resistance” during phagocytic predation by the protozoan Tetrahymena thermophila. PNAS. 103:165-170.

Cell Signaling and Cancer: Justin Waguespack

If there was a dictionary for all the scary words in the world, cancer would be near the top, with college as a close second. Cancer is one of the leading causes of death world-wide because of its devious nature. Cancer cells have the ability to attack different types of cells to avoid apoptosis which is the death of a cell that is harmful or may not be functioning properly. In 2003, the Beatson International Conference on Cell Signaling and Cancer took a closer look at cell signaling as a possible mechanism to combat cancer.

Cancer 3

Cell signaling is continuously happening throughout our body, and it allows for growth, cell structure, respiration, muscle signaling, and almost any other process that allows our bodies to function. The problem with cancer cells is that they are unstable and cause mutations in normal cellular signaling processes. Late detection and symptoms of cancer often lead to high mortality rates, and it can be tricky to kill the evasive cancer cells without attacking healthy human cells.

Cancer 4

One method the Beatson International Conference on Cell Signaling and Cancer discussed as a possible method to prevent cancerous cell growth was to use cell signaling inhibitors. Remember, cancer cells are evasive and can attack multiple cells, but Raf proteins were discussed at the conference as a possible target for therapeutics. The Raf protein is special because it can form three different conformations. The most abundant conformation is the B-Raf. Mutations to the B-Raf protein is commonly found in melanoma and other types of cancer. The Institute of Cancer Research, Landon found that mutations of the B-Raf protein can be blocked by downregulation of RNAi. This finding is significant because blocking the B-Raf protein from being mutated would allow for the cancer cells to undergo apoptosis. The conference may not have created a solution to stop cancer completely, but understanding the relationship between cell signaling pathways and cancer cells is a huge step in the fight against cancer.


Martin, G S. (2003). Cell Signaling and Cancer. Current Neurology and Neuroscience Reports. U.S. National Library of Medicine. 4:167-173. Print.

Modulation of Phagocytosis in Tetrahymena thermophila by Histamine and the Antihistamine Diphenhydramine by Shelby B.

Almost anyone would agree springtime is enjoyable- with the nice weather and all those pretty flowers blooming- but no one enjoys the itchy, puffy eyes, sneezing, and congestion that come with spring allergies! If the symptoms are very bothersome, you may take an allergy pill to get some relief. Most people don’t think much about it, but this is an example of histamines and antihistamines working in your body and affecting your daily life!

Funny, Happy, and Weather: When ur happy the warm weather is
 finally here but the pollen count is 1 million
Relate-ability to the max. (@tank.sinatra)

Histamines are molecules in the body that cause allergy symptoms and swelling. Antihistamines counteract or reduce the effects of histamines. For example, diphenhydramine, also known as Benadryl, is an over-the-counter antihistamine you have probably used at least once in your life. Diphenhydramine is cheap and easy to obtain, making it useful in studying histamine/antihistamine effects.

When studying molecules that have an effect on the human body, it is important to use model organisms. A great model organism is one that reacts similarly to humans to a certain stimulus (in this case histamines/antihistamines) and is easy to obtain, grow, and examine. This definition is why many researchers use Tetrahymena spp. , single celled organisms that behave very similarly to human immune cells and are cheap and easy to keep alive and observe.

In this illustration, a eukaryotic cell is shown consuming a bacterium. As the bacterium is consumed, it is encapsulated into a vesicle. The vesicle fuses with a lysosome, and proteins inside the lysosome digest the bacterium.Image result for macrophage phagocytosis

*An example of phagocytosis in Tetrahymana spp. and a human immune cell*

       A study by Buduma et. al. used Tetrahymena thermophila to test the effects of histamines and the antihistamine Benadryl on the rate of phagocytosis (food uptake) of the cells. It is important to study this because human immune cells use phagocytosis in our bodies to keep us healthy, and histamines and antihistamines affect this process. The study found that histamines had no effect on the Tetrahymena, but the Benadryl decreased phagocytosis, which meant the cells had a receptor for antihistamines but not histamines. These results mean Tetrahymena thermophila can now be used to test the effects of new antihistamine drugs quickly and easily!


Buduma, N., (2013). Modulation of Phagocytosis in Tetrahymena thermophila by Histamine and the Antihistamine Diphenhydramine. ACTA Protozoologica, 52, 317-323. doi:10.4467/16890027AP.13.029.1321


Plants as Epigenetic Models: Brooke Savoie

There are more factors that control the way organisms look and function beyond the realm of genes. The genotype, or genetic composition of an individual was thought to solely determine the characteristics of that individual. Epigenetics is the change in how genes are expressed without actually changing that gene itself. The expression of genes can be changed by things such as environmental factors, so even organisms with identical genetic compositions can be different.

Image result for epigenetic meme

Some epigenetic information can be passed down to further generations. Source

Plants have been used in the study of epigenetics due to their versatility. Plants can be easily modified and are so diverse that they are the perfect candidate. For plants to survive in their environment they must be adaptive and overcome adverse conditions such as weather. Because of the non mobile nature of plants they must be able to adapt since they can’t just get up and move. It was found that plants have the same types of gene regulation that many eukaryotic organisms. Arabidopsis thaliana which is a mustard plant has been the center of epigenetic studies since it was the first plant to have its genome sequenced. With the mustard plant, individuals with the same DNA sequence had variable expression of genes which contributed to the time of their flowering. In response to different environmental factors a plant can modify the expression of genes that can help the plant survive and thrive in it’s specific circumstances.

Plant models have given insight to how gene regulation and expression occur in other organisms. Plants and animals may seem completely different but there are more similarities than meet the eye. Both plants and animals have the similar ways of controlling gene expression through methylation of DNA. A genetic disorder that was first found and studied in maize was also found to affect humans which is caused by a phenomenon called parental imprinting. For every gene only one variation or allele is expressed in an offspring the other allele must be silenced, either the one from the mother or the one from the father. Parental imprinting can have some mutations and is the reason for some disorders which is a good reason to study how this mechanism works in plants.

Because of the agricultural industry the study of epigenetics may have some implications in how to grow more successful and resilient crop. Epigenetics of wild mustard are the reasons for the vegetable variety that we enjoy today. The variability of the expression of traits allow for such so much variety in plants.

Image result for epigenetic plants

All the plants above were derived from the selection of wanted traits from wild mustard plants. Most of the vegetables are of the same species Brassica oleracea. Source


Pikaard, C. S., & Mittelsten Scheid, O. (2014). Epigenetic regulation in plants. Cold Spring Harbor perspectives in biology6(12), a019315. doi:10.1101/cshperspect.a019315

(2009). Genomic imprinting disorders in humans: a mini-review. Journal of assisted reproduction and genetics26(9-10), 477-86.



Using Molecular Approaches to Combat Illegal Wildlife Trade by Emily Ford

The illegal trade of wildlife (plants, animals, and their byproducts) is the second largest threat facing endangered species today, outranked only by habitat destruction. Frequently trafficked species span all ecosystems in every part of the world, making the $20 billion/year market incredibly difficult for law enforcement to handle. Most trade occurs along existing drug smuggling routes, and once wildlife is seized, it’s often tough to pinpoint where exactly these species came from– that’s where molecular genetics comes in.


Turtles are one of the most threatened species worldwide, with 51% of their species extinct, endangered, or vulnerable of becoming endangered. (Image source)

In the past, identifying trafficked organisms was based primarily on recognizing physical traits unique to each species. Unfortunately, this requires the plant or animal to be mostly intact, and is almost useless in identifying the origins of byproducts often seized (such as ivory, cooked/dried meats, feathers, etc.); however, molecular approaches require only a small sample of DNA, making them the preferred method of species identification in these instances.

Each cell contains multiple copies of mitochondrial DNA (mtDNA) because there are several mitochondrion inside. Plant and animal cells only contain one nucleus a piece (generally), meaning that mtDNA is more likely to be found in a sample (like decomposing tissue) than nuclear DNA (nDNA). Segments of mtDNA can be copied over and over again using a process known as the polymerase chain reaction (PCR), which allows genes (like Cyt b or CO1) to be identified easily. The differences in DNA patterns within these genes is what makes each species unique– that’s how they’re able to be identified. heraa-hashmi-atcaveheraa-mitochondria-is-the-powerhouse-of-the-cell-false-mitochondria-are-the-powerhouses-of-the-cell-mitochondria-is-plural-the-singular-is-mitochondrion-if-thats-the-o

Having multiple mitochondrion in each cell makes mtDNA the preferred genetic marker for identifying a degraded sample’s species of origin. (Image Source)

In terms of conservation efforts, simply identifying a species isn’t enough– it’s important to determine where these organisms are starting their trafficked journey. “Phylogeography” refers to the relationship of very similar genetic patterns (like those found in mtDNA) and their location across the globe. A species’ region of origin can be determined by comparing it’s mtDNA sequences to what we already know about the mtDNA of similar species living in different parts of the world.


Phylogeographic methods were used to compare seahorse species Hippocampus barbouri, H. spinosissimus (pictured here), H. trimaculatus, and H. ingens to pinpoint the birthplace of seahorses listed for sale in Californian traditional medicine shops. (Image Source)

Not only is the trafficking of species cruel to individual organisms, it disrupts their home ecosystems by removing key players from their natural balance, while simultaneously exposing species to foreign diseases they have no immunity against. The methods described above, in part with harsher legal consequences for traffickers, can help decrease illegal wildlife trade, therefore improving the overall health of species everywhere.

Source: Alacs, et al. (2009). DNA detective: a review of molecular approaches to wildlife forensics. Forensic science, medicine, and pathology. DOI: 10.1007/s12024-009-9131-7.




Segregated Human Pedigree Analysis by DNA Fingerprints By J. Munoz

Human pedigree analysis, also known as the “genetic family tree,” shows certain genetic traits that have been through generations between families. Determining a carrier for a genetic disease is one of the ways these pedigrees are useful. The use of DNA fingerprinting, in a study of Jeffreys et al., extended their research in a co-segregated research with human pedigrees. To help with the pedigree, they first used RFLPs (Restriction Fragment Length Polymorphisms). On how that works, DNA is digested with a restriction enzyme that cuts DNA at a specific site making hypervariable minisatellite fragments. 

Everyone’s DNA is specific on the way that its cut. The cut fragments are gel electrophoresed with two different probes (33.6 and 33.15) to obtain different sets of fragments and allow a better scoring of hypervariable minisatellites. It will display different patterns of segments revealing the DNA fingerprints that are individual-specific. This starts the linkage analysis in man.RFLP genotyping

Example of how RFLPs can associate with pedigrees. *(This picture is not related to the study of Jeffrey et al.)*

The picture above helps one understand which siblings has the same specific DNA cuts from each parent. One parent’s DNA can be unavailable, but it can still manage to construct the pedigree with the help of RFLP in identifying parental minisatellite fragments present in some siblings but absent from the father. 

Using this analysis of DNA fingerprints the study was able to become a pedigree of Gujarati Asians. Jeffreys et al. were able to form 2-four generations with the determination of hypervariable fragments. This co-segregated study was able to determine the transmission in hereditary persistence of fetal hemoglobin in the sibship (siblings from the same two parents) and other generations as well.

The different probes allowed to obtain about 34 isolated minisatellite for hypervariable loci to determine loci that is closely linked to a given disease loci to help in distinguishing a disease gene. This approach is very helpful in linkage data to locate minisatellites in other human genomes to detect affected families in future generations.


Article Source: Jeffreys, A J et al. “DNA ‘Fingerprints’ and Segregation Analysis of Multiple Markers in Human Pedigrees.” American Journal of Human Genetics 39.1 (1986): 11–24. Print.

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The Use of DNA Fingerprinting in Identifying Diseases by Seth Browning

Individuals can be identified as part of a group in a number of ways.  Besides identifying someone based on physical appearance, a person can be labeled through the use of genetic testing.  One of these mechanisms is the usage of DNA fingerprinting.  DNA fingerprinting is the use of polymerase chain reaction (PCR) and gel electrophoresis to determine the genetic makeup of a DNA sample.  With these two techniques, we can distinguish DNA samples between individuals.  PCR makes multiple copies of DNA and amplifies the specific sequence that researchers want to observe.  Gel electrophoresis allows the researcher to match the DNA being tested with the original DNA.  The similarities of the DNA are based upon the number of short tandem repeats within the genetic sequence.  In a study completed in 1994, DNA fingerprinting was used to determine which tuberculosis samples were latent infections and which were transmitted within the community.

Tuberculosis (TB) is caused by Mycobacterium tuberculosis, and mostly colonizes the lungs.  The signs and symptoms of TB include a persistent cough which can be accompanied by the presence of blood or phlegm, chest pain, fatigue, weight loss, absence of appetite, chills, fever, and night sweats.  There has been an increase of TB cases since the 1980s.  New York City has contributed to 14% of these cases, and researchers believe that most individuals with TB are homeless or part of the minority population.  To distinguish between the different TB strains in New York City, researchers used DNA fingerprinting.  After gathering 104 patients that tested positive for TB, the DNA from the bacteria were extracted.  Enzymes used to digest the extracted DNA included PvuII and AluI.  The samples then underwent PCR and gel electrophoresis.  After examining the fingerprints, the researchers divided the samples into two groups.  Group 1 contained nonclustered isolates that produced a unique fingerprint and Group 2 which contained clustered isolates.  Of the 104 samples, 62.5% consisted of Group 1 and the other 37.5% consisted of Group 2 strains.  This study concluded that the transmissible strain of TB caused more cases than TB strains that reactivated during adulthood.  DNA fingerprinting allowed scientists to distinguish between different strains of M. tuberculosis.  This has proven that DNA fingerprinting is a promising tool.  This instrument can be also used to predict future strains of bacteria that are responsible for outbreaks when looking at a large population.



Alland D, et al. 1994. Transmission of Tuberculosis in New York City: An Analysis by DNA Fingerprinting and Conventional Epidemiologic Methods. NEJM. 330:1710-1716.


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The Woes of DNA Fingerprinting by K. Gleason

DNA fingerprinting has more uses than solving crimes, like murder; it is also employed in paternal cases to identify a child’s father. DNA fingerprinting, or DNA profiling, is a technique that is used to determine a genetic match between people and samples that are found at crime scenes. The genetic material is retrieved from a variety of cells, like semen, blood, skin cells, and saliva. Everybody has their own unique DNA fingerprint, unless they are identical twins. Like all innovative sciences and technologies, there are some controversies surrounding DNA fingerprinting.

One of the most prominent controversies is the reference population that forensic scientists use. The reference population is a general template of what someone’s DNA would look like from a certain population (Caucasian, African American, etc). The biggest concern with the use of reference populations is that there are subpopulations (German, Irish, etc) within these ethnicities. It was assumed for a long time that people only married and had children with others in their subpopulation, but with the modernization of relationships, people are starting to marry outside of their subpopulations and even ethnicities. These populations are expressing increased variability, which means the chances of having two people with matching DNA is slim to none, especially in the US, which is considered a “melting pot” of cultures and genetics. To remedy this outdated reference population system, new databases are being made. These new databases will ignore the subpopulations and look only at ethnicity unless some populations are incredibly different, like the different tribes of Native Americans, which is when the databases are separated by region in case there is small variability.

To guarantee that no other controversy could arise about the uniqueness of a person’s DNA, scientists studied how many genotypes could be observed. They found that the number of possible genotypes far exceeded the population of the US and the chance of two people with the same genotype (excluding identical twins) was 10 raised to the negative 12, which means that it is negligible.

Since we are always shedding skin cells and hair, our DNA is everywhere. DNA fingerprinting is used to place a suspect at a crime scene or to get some basic information about the people that were there, like their gender and ethnicity. While most of us know that DNA fingerprinting is used to place a suspect at the scene, it can also be used to exonerate suspects. A boy that was a suspect of raping and murdering two females in England requested a blood test to prove that he didn’t do it. The blood test showed that he was indeed innocent of the crime, preventing an innocent person from being imprisoned. If there had been a lab error, his case could have ended differently. Lab errors can occur when the same sample is tested twice, there is a high number of different DNA profiles analyzed, and chain of custody problems. There aren’t really any solutions to these concerns other than the lab being careful and proper protocol being followed. As science advances, these concerns could vanish or open the door for even greater concerns to emerge.


Roeder, K. (1994). DNA Fingerprinting: A Review of the Controversy. Statistical Science, 9(2), 222-278. doi: