Lighting up Life with GFP

NEWS_1.27.15_jellyfish.jpgMeet the luminescent Aequorea victoria. This jellyfish lights up the eastern Pacific Ocean with a green fluorescent signal. Producing this signal is a two steps process. First a blue light is created through an interaction between released calcium (Ca2+) and the protein aequorin. Then the blue light is turned green by a protein known as Green Fluorescent Protein (GFP).  Both proteins have become powerful tools in biotechnology. GFP in particular has revolutionized the fields of cell and molecular biology. Because GFP exhibits bright green fluorescence when exposed to blue light, it is used as a visualization tool in fluorescent microscopy.

GFP is made out of 238 amino acids whose order is encoded on a stretch of DNA. This stretch can be inserted into a gene (at the end of the gene but before the stop codon). The NEWS_1.27.15_255.jpgresult is a bit like attaching a light bulb to the end of the protein, every time the gene is express GFP is also produced and the invisible protein is suddenly visible. This allows scientists to watch the movements, positions and interactions of the proteins. In such cases GFP is called a fluorescent “tag” and the protein is a “tagged” protein.

There are a couple of properties that make GFP an especially good tag. One is that GFP does not harm the cells it is introduced into. This means that proteins can be visualized in living cells. Another is that GFP is very self-sufficient – it doesn’t require any accessories or cofactors or enzymes or substrates (other than molecular oxygen) in order to convert blue light to green fluorescent light.  Finally GFP is small, so small that even when attached to another protein that protein is not affected. 

GFP has been used to explore biochemical and cellular processes in living cells. By staining proteins specific to certain cells it has also been used to study cell location and movement within whole organisms. Often it is used as a reporter gene. This means that it tells us how successfully another gene has been introduced. For experience with this bright and versatile protein check out kits 858 (Lighting Up Life: Expression of GFP in C. elegans), 223 (Transformation of E. coli with Green Fluorescent Protein), and 255 (Purification & Size Determination of Fluorescent Proteins).

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Biotech Basics: An Introduction to Cell Biology

RobertHookeMicrographia1665.jpgThe basic unit of all living organisms, from bacteria to humans, is the cell.  Robert Hooke first described the cell in 1665, when he used a microscope to examine a piece of cork.  To his eyes, he saw an orderly pattern of “a great many little boxes,” or holes separated by thin walls much like a honeycomb.  A few years later, and with a more sensitive microscope, Antoni Van Leeuwenhoek visualized the first living cells darting around water droplets, which he called “very little animalcules.”  This was likely the first description bacteria and protists, which we can observe in a drop of pond water today.

Nowadays, we know that living things are made of cells.  However, not every cell is the same.  Bacterial cells differ from protists, which differ from animal cells.  Some organisms consist of one cell (unicellular), and others consist of multiple cells (multicellular).  Furthermore, within a multicellular organism, there can be many types of cells working together in structures like tissues and organs to build a complex organism.

So how can we learn more about these amazing building blocks of life?  Using microscopy and techniques from biochemistry, physiology, and molecular biology, cell biologists investigate the structure and function of the cell and its components, and how the distinct parts of a cell work together.  Let’s explore cells in your classroom laboratory!

Membranes and Transport:

At its simplest, a cell is essentially a drop of a thick, watery substance (cytoplasm) surrounded by a layer of fats (cell membrane) that form a barrier between the inside of the cell and the outside environment.  The cell membrane consists of two layers of lipids embedded with proteins that move ions and other molecules into and out of the cell.

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Organelles:

Contained within a cell is the genetic material (DNA), and the cellular machinery necessary to create proteins (ribosomes).  However, that is where the similarities between all cells end.  Through their experiments, scientists identified two distinct types of cells – prokaryotes and eukaryotes.  Contained within eukaryotic cells are a diverse collection of membrane-bound compartments (organelles) that each have a specific biological function.  In contrast, prokaryotic cells do not have organelles; instead all biological materials are present in the cytoplasm.

987Nucleus:  Contains DNA, acts as a cell’s control center.

Ribosome:  Links amino acids together to form proteins.

Mitochondria: Cell’s powerhouse, converts food to energy.OO-001

Chloroplast:  Uses sunlight to create food for plants.

 

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Cell morphology refers to the shape, appearance, and structure of a cell. The structure of a cell relates to the functions of the cell, whether it is prokaryotic or eukaryotic.  In prokaryotes, researchers observe the shape and arrangement of cells to identify the species of bacteria. In higher organisms, the morphology of cells relates to the tissue from which they originated.  Changes in a cell’s morphology indicate diseases like sickle cell anemia or cancer.

 

Cell division:

All cells divide in order to create more cells.  In most cases, one parent cell will split into two identical daughter cells.  This allows an organism to grow, to develop, and to replace old cells.  In order for a cell to divide, the cell must increase in volume, duplicate its DNA, and then split all of the cellular components into two separate cells.   This process must be carefully regulated to ensure that the cell divides at the right time and in the right place.  Rapid, unregulated cell division can result in a group of diseases called cancer.   Cancer changes the nature of the cells, which can be identified using biomedical tests.

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November 14th is World Diabetes Day

NEWS_2.19.16_Diabetes_ThumbDiabetes — chances are you know someone who has been affected by this disease.  But, what is diabetes, medically speaking?  The term diabetes can refer to a group of chronic diseases that occur when there are increased levels of blood sugar over a prolonged period of time. In general, diabetes can develop when the pancreas cannot produce enough insulin, or when insulin cannot be properly processed by our cells. In either of these cases, the glucose in the blood will not be utilized efficiently. In addition, the resulting high blood glucose will cause a number of symptoms including frequent urination, increased thirst and hunger, and weight loss. The body can also switch to burning fatty acids rather than using glucose for energy. In this situation, the fatty acids are converted into ketone bodies through beta-oxidation to release energy. Over time the ketone bodies will accumulate in blood and decrease the pH, ultimately disrupting the buffering system in blood. The resulting “diabetic ketoacidosis” can be a life-threatening complication of diabetes. Other diabetic complications include stroke, diabetic neuritis and vision loss. These long-term complications are very severe and can be fatal if untreated. 

NEWS_2.19.16_Symptoms_Fig2.jpgDiabetes is a common but severe long-term metabolic disease. The World Health Organization’s 2014 data indicates that about 9% of the global adult population (age > 18) suffered from this disease and more than 1.5 million people died from complications caused by diabetes. Governments and private companies invest huge amounts of money into research to fight diabetes each year. At the same time, improving education about the causes and symptoms of this disease is critical in preventing diabetes and performing early treatment to patients. 

There are three main types of diabetes. 

  • Type I diabetes, sometimes referred to as “insulin-dependent diabetes mellitus” or “juvenile diabetes”, happens when the pancreas loses its ability to produce insulin. The development of this kind of diabetes is complicated. Often, type I diabetes results from an autoimmune response where the pancreas beta cells are attacked and destroyed by a patients own immune cells. Without the beta cells the pancreas can no longer produce insulin. Type I diabetes usually happen in juvenile age, though it can arise later in life. 
  • Type II diabetes is caused by insulin resistance, where the patients cells will no longer react properly to insulin. Because of this, type II diabetes is also known as “non-insulin-dependent diabetes mellitus”. Type II diabetes often occurs in adults, usually as a result of obesity and a lack of exercise.
  • Gestational diabetes is a condition where a pregnant woman has a high level of blood sugar without being diagnosed with diabetes before the pregnancy. Similar to type II diabetes, patients with gestational diabetes do not properly respond to insulin, leading to elevated blood sugar. Gestational diabetes typically disappears after the baby is born.

Different treatment strategies need to be adapted for the different types of diabetes. Type I diabetes patients often require insulin injections, while some type II patients are able to maintain a healthy life style through changes in exercise and a diet. Although gestational diabetes is often resolved after giving birth to the baby, it is always taken seriously since it can cause severe problems to both the mother and the baby. 

Would you like to explore the detection and diagnosis of diabetes with your students? Check out kit #280 – Detecting the Silent Killer: Clinical Diagnosis of Diabetes. Your students will examine two different methods to detect diabetes and then use their results to diagnose simulated patients.

 

Seeing (and trying) is believing

workshop 11_11 hor.pngHave you ever wanted to try Edvotek® kits or equipment before making the investment?  You’re in luck!  In November and December, we’re traveling all over the country with a fantastic series of biotechnology experiments in tow.  Be sure to join us at an upcoming conference in your neighborhood!

For more information on the workshops, visit our complete event schedule.  We post presentations and resources on this page for your reference.  We can’t wait to meet you!